ISSN 0031-0204

Transactions and Proceedingsof thePalaeontological Society of Japan
New SeriesNo. 138

Palaeontologica l Society of Japa n
Jul y 15, 1985

Co-Editors

Takashi HAMADA and Hisayoshi IGO

Officers for 1985-1986
President: Toshimasa TAN AI
Honorary President: Teiichi KOBAYASHI
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Itaru HAYAMI, Hisayoshi IGO, Junji ITOIGAWA, Tadao KAMEl, Tatsuaki KIMURA,
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The fossil on the cover is Unuma (Spinunuma) echinatus ICHIKAWA and YAO, a
Middle Jurassic multisegmented radiolaria from Unuma, Gifu Prefecture, central
Japan (photo by A. YAO, x 260).

All communication relating to this journal should be addressed to the

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Trans. Proc. Pelaeont. Soc. Japan, N. S., No. 138, pp. 79--93, pis. 10-13, July 15, 1985

795. EARLY PALEOGENE SILICOFLAGELLATES AND EBRIDIANSFROM THE ARCTIC OCEAN*
HSINYI LING
Department of Geology, Northern Illinois University, DeKalb, Illinois 60115

Abstract. Subsequent to the finding of Upper Cretaceous (Maastrichtian?)
submarine sediments from FL-437, another unusual core, FL-422, was recognizedfrom the Fletcher's Ice Island T-3 in the Alpha Ridge region of the Arctic Ocean. In
spite of a superficial lithological resemblance to the previous FL-437 cored sediments, the silicoflagellate and ebridian assemblage identified from the FL-422
marine deposits is best considered as Early Paleogene age. Its microfloral composition is distinctly different from all the previously published records of this group ofsiliceous microfossils of other parts of the world. The following new taxa areproposed:
Dictyocha arctios, D. curta, and Ammodochium fletcheri. This report of
Early Paleogene silicoflagellates and ebridians reconfirms the existence of preMiocene deep-sea sediments in the Alpha Ridge area of the Arctic Ocean, thus
providing paleooceanographic evidence about geophysical and tectonic paradigmof the Arctic Ocean floor.

Introduction

is compared with the available records of thisgroup of microfossils from other parts of theworld, including those from the land outcrops
and submarine deposits.
This paper reports the silicoflagellate andebridian assemblage including new taxa, refines
the earlier age estimate to Early Paleogene,and discusses its significance with sea-floor
spreading and plate tectonic paradigm of the
Arctic Ocean.

The recovery of an unusual sediment core,FL-437 (Text-fig. 1), from the Alpha Ridge areaof the Arctic Ocean, and the subsequent age
identification of the sediments as Late Cretaceous (Maastrichtian?) based on the contained
silicoflagellate assemblage (Ling et al., 1973),
provided the first documentation of the occurrence of pre-Pliocene sediments in the Arctic
Basin.
Another interesting deep-sea sediment core,FL-422 (Text-fig. 1), was recovered from thesame area and its unique nature was apparent
even at preliminary examination when a Paleocene-Eocene age was suggested (Clark, 1974;
Kitchell and Clark, 1982). First, the sediments
are silicoflagellate-diatom ooze and second, thesilicoflagellate assemblage is distinctive when it

Material studiedCore FL-422 was collected at 84°53.48'N,
142°32.87'W at a water depth of 2,049 metersfrom the Fletcher's Ice Island T-3 on July 20,
1969 (Text-fig. 1). The core is 364 cm long. The
uppermost 12 cm is a "normal" Arctic graybrown (10YR 4/4) lutite, rich in typical coldwater planktonic foraminifera, "Globigerina"*Received September 3, 1983.
79

Hsin Y. LING

80

120°

90 0 W

60°

Text-fig. 1. Index map of Arctic Ocean showing the location ofcore FL-422 studied in this paper. The position of the Late Cretaceous (Maestrichtian?) silicoflagellate-bearing sediment core FL-437 isalso indicated.
pachyderma. Below this is 169 cm of yellow toyellow orange (10YR 6/6) siliceous oozes withsome darker clasts. Four samples from thissequence revealed that they contained up to 60%
montmorillonite with 10-20% illite, chlorite andkaolinite. Underlying this middle unit is 183 cm
of dark brown to black (10YR 2/1) siliceous
oozes, more like normal Pleistocene Arctic sediments. All contacts may be unconformable(Clark, 1974; Kitchell and Clark, 1982). As inprevious investigations from the area (Ling et al.,1973), cores were cut into 15 cm segments andnumbered consecutively upward. Samples werealso taken at 5 cm intervals throughout the coresfor paleomagnetic polarity measurement. All thesamples showed normal polarity, with the exception of 9 samples from 22 to 57 cm below the
top of the core, which showed reverse polarity.
This polarity sequence could not be correlatedwith any known Pleistocene-Pliocene magnetic
sequences in the Arctic (Clark, 1971, 1974).
In the cored sediments, specimens of planktonic foraminifera, "Globigerina" pachyderma
and a few Globigerina quinqueloba were found.

"G." pachyderma were abundant in the upper
12 cm (segment 24), and although rare, were also
found in the next lower 18 cm and in the bottom
segment of the core (Clark, 1974).
Systematic paleontology
Utilizing procedures similar to the previous
studies for this group of siliceous microfossils(e.g., Ling, 1970, 1972; Ling etal., 1973), coredsediments (from the center of each 15 cm segment) were chemically treated prior to thedetailed examination under the microscope.
Terminology employed throughout the present
paper for silicoflagellates is as described previously (Ling, 1972), and for those ebridians, after
Deflandre (1934, 1951), Ling (1972), andLoeblich, III. et al. (1968). Observation under ascanning electron microscope, JSM-U3, was madefor some selected taxa to examine their surface
microstructures.
Slides containing type specimens with USNM
numbers will be deposited in the National
Museum of Natural History, Smithsonian Insti-

795. Paleogene Silicoflagellates and Ebridianstution, Washington, D.C. and all the remaining
slides and negatives of the scanning electron
microscopy used for the present investigation
will be deposited permanently in the micropaleontology collection of the Department of
Geology, Northern Illinois University, DeKalb,
Illinois.

81

ties of Russia ranging in ages from Early Paleocene through Early Oligocene, and by Bukry(1976a) from the Paleocene section of Hole
327 A of the Falkland Plateau. However, thepresent Arctic specimens can be differentiatedfrom them by its possession of definite shortradial spines at the three apices and by the lesselevated apical structure.

Order Siphonotestales Lemmermann, 1901a
Genus Gorbiserna Hanna, 1928

Gorbiserna triacantha (Ehrenberg)

Gorbiserna apiculata (Lemmermann)

PI. 10, Fig. 7; PI. 12, Fig. 1.

PI. 10, Figs. 1, 2.

Dictyocha triacantha Ehrenberg, 1844, p. 80.
Gorbiserna triacantha (Ehrenberg), Hanna, 1931,
p. 198, pI. D, fig. 1.

Dictyocha triacantha var. apicuiata Lemmermann,
1901b, p. 259, pI. 10, figs. 19,20.
Gorbiserna apicuiata (Lemmermann), Frenguelli,1940 (in part), fig. 12 h; Ling, 1972, pp. 151,
152, pI. 23, figs. 13-17.

Genus Dictyocha Ehrenberg, 1838
Dictyocha sp.

PI. 10, Figs. 8-11; PI. 12, Figs. 2-4.
Gorbiserna hastata hastata (Lemmermann)

PI. 10, Figs. 3,4.
Dictyocha triacantha var. hastata Lemmermann,
1901b, p. 259, pI. 10, figs. 16, 17.
Gorbiserna hastata hastata (Lemmermann), Bukry
1976a, p. 892.
Gorbiserna sp. cf. G. inerrnis minor (Glezer)

PI. 10, Figs. 5,6.
Dictyocha triacantha var. apicuiata fa. minor
Schulz, Gemeinhardt, 1930, p. 42, fig. 31.
Not Dictyocha triacantha var. apicuiata fa.
minor Schulz, 1928, p. 249, figs. 29 a, b.
Not Dictyocha triacantha var. inerrnis f. minor
Glezer, 1966, p. 231, pI. 8, figs. 3-5; pI. 31,
fig. 7.
Not Gorbiserna inerrnis minor (Glezer), Bukry,
1976a, p. 892, pI. 5. fig. 47.
Rernarks:-The specimens from the core FL422 appear to be identical to the form observedby Gemeinhardt (1930) from Oamaru, New
Zealand. These specimens possess round apicesof the basal body ring as well as very short but
definite radial spines at the apices. The specimens, beyond any doubt, closely resemble those
illustrated by Glezer (1966) from various locali-

Description:-Basal body ring, rhombic, withwell developed radial spines of approximately
equal length to the respective axis; lateral rods,
also well developed, intersecting nearly perpendicular to the outline of the basal ring in either
apical or abapical view, joined on the apical sideof the basal ring, and extending well beyond thebasal ring; major and minor axes intersect slightly
obliquely; apical bar, short, generally on the
direction of major axis, but some also on minor
axis; neither apical or basal accessory spines
present.

The surface microstructure of the species
shows a reticulate pattern on the abapical side of
the basal ring (PI. 12, Figs. 2, 3), but a nearlysmooth, or very weak, if present, reticulate
pattern on the apical side (PI. 12, Fig 4);
whereas the apical bar and lateral rods are finely
reticulate on the apical side (PI. 12, Fig. 4),
and definitely reticulate on the abapical side
(PI. 12, Fig. 3).
Rernarks:-Undoubtedly the present species
is similar to D. frenguellii Deflandre (1950,
p. 66, 82, figs. 188-193) or D. t. var. frenguellii
by Glezer (1966, p. 240, pI. 11, fig. 9) in its
general configuration. However, it differs from

Hsin Y. LING

82

them by its larger size, much developed lateralrod extensions, and the rhombic rather thanquadrate or square-shaped basal ring. It also
lacks basal accessory spines.
Bukry (1984) referred the specimens of thepresent taxon to his two subspecies, Dictyocha
aspera martini and D. fibula formicata. The
major difference of these two subspecies is theorientation of an apical bar either on or trans·versal to major axis. Unfortunately, the present
Arctic specimens show both directions, although
preference seems to be along the major axis.
SEM observation of the specimens failed toreveal any difference on their surface microstructure.
Thus the present species includes a part ofDictyocha aspera martini (Bukry, 1975, p. 854,
pI. 2, figs. 5?, 6, 8 (only); 1984, p. 199, fig. Ie).
As to Dictyocha fibula formicata, Bukry (1975,
p. 854) differentiated it from D. frenguellii of
Deflandre (1950) by an absence of "a modified
apical plate", but in the original description,
Deflandre (1950, pp. 66--67) stated only:" .. baguette apical courte, typiquement elargie
mais non aplatie, l'aire apicale formee restantcreuse; .... " and never mentioned the presenceof such a plate structure. Therefore, further
comparative study, particularly samples fromthe southern ocean, is necessary in order toclearly the taxonomy of the present Arctic
species.

Dictyocha arctios Ling, n. sp.
PI. 10, Figs. 12-15.

Description:-Basal ring, square, with a slightindentation in the outline where the lateral rods
originate; radial spines, longer or approximately
equal in length with the diagonal dimension of
the basal ring; lateral rods straight, intersecting
near the center to form a letter X, or with a very
short apical bar; apical spine projects upward;
both apical and basal accessory spines, absent.
Derivation of name:-The new species isnamed after the Arctic Ocean.
Remarks:-The general appearance of this new
species calls to mind some of the specimens

illustrated previously by various workers as D.
staurodon Ehrenberg. Therefore, the following
discussion is in order.
A silicoflagellate species, Dictyocha staurodon,
was originally proposed by Ehrenberg (1844,
p. 71; p. 80) and illustrated later by him (1854,
pI. 18, fig. 58) from a Miocene sample ofRichmond, Virginia. His specimen showed arhombic basal ring, short radial spines, basal
accessory spines, and above all, a very small
square-shaped apical window. The presence of
this apical structure was later confirmed byLocker (1974, p. 640, pI. 3, fig. 10) after
his reexamination of the original Ehrenberg's
collection. He correctly identified the species asDistephanus crux under the widely accepted
present-day classification scheme, and thisreassignement has already been adopted, e.g.,
Bukry (1977, p. 687).
A literature survey has revealed that thefollowing forms have been incorrectly assigned to
Dictyocha staurodon:
1. forms with long radial spines, straight lateralrods and with an apical spine only; Schulz(1928, fig. 34 C) from Bremia.
2. forms with long radial spines, straight lateralrods and with both apical and basal accessory
spines: Lemmermann (1901b, pI. 10, fig.
22; 1903, fig. 91) from the Atlantic.
Gemeinhardt (1930, fig. 38b) from Bremia.
3. forms with long radial spines and an apicalaccessory spine, but with curved lateral rods
and basal accessory spines either present orabsent: Schulz (op. cit., figs. 34a, b) andGemeinhardt (op. cit., fig. 38a) from Dolje.
4. forms with short radial spines but straightlateral rods and an apical accessory spine as fa.
minor: Schulz (op. cit., fig. 38d) from
Kusnetzk; or without an apical spine, Mandra(1968, p. 253, fig. 65) from California and
Zanon (1934, p. 66, figs. 9, 10) from Italy.
5. forms with short radial spines and both apicaland basal accessory spines but curved lateralrods: Schulz (op. cit., fig. 34f) and Gemeinhardt (op. cit., fig. 38c) from the Atlantic Ocean.
A specimen from Bremia illustrated by795. Paleogene Silicoflagellates and Ebridians
Schulz (op. cit., fig. 34c), referred to as"Bremia bei Kavna, Hungary," and as SannatianStage by Loeblich, III. et al., (op. cit., p. 17) may
undoubtedly be conspecific with the present
species. However, it seems reasonable to propose
them as separate species in view of first, theirchronostratigraphic differences, Paleogene vs.
Miocene; and second, because thus far there is nosubsequent record of the species from any partof the world, including the submarine deposits
recovered by DSDP.
Measurements:-Length on major axis of basal
body ring, 36-42 Ilm; of basal spines, 24-36 Ilm.
Types:-Holotype, USNM 395821; Isotype,
USNM 395822.

Dictyocha sp. cf. D. carentis incerta (Glezer)
PLIO, Figs. 16, 17; PI. 13, Figs. 1-3.
Dictyocha frenguellii var. carentis fa. incerta
GIezer, 1964, p. 52, pI. 1, figs. 15, 16; GIezer,
1966, pp. 241, 242, pI. 11, figs. 14-16.
Dictyocha cf. D. carentis Glezer, Perch-Nielsen,
1975a (in part), p. 686, pI. 4, fig. 6 (only).

Remarks:-It is agreed with Perch-Nielsen(1975a) and Bukry (1976a, p. 893) that Glezer's
variety should be raised to specific rank. Separation seems warranted because D. frenguellii proposed originally by Deflandre (1950) fromthe Eocene diatomites of Isenski, Singhiliewski(or Cenghileevsky) and Kamischev of Russia - isquite different from the present taxon in its
apical configuration as well as in its dimensions.
Based on the observation of specimens underboth transmitted and scanning electron microscopes, . it is advisable to consider the present
taxon as having the following characteristics:(1) the shape of the basal body ring is circular;(2) the radial spines are all short, of equal dimension, and truncated at the distal end, and (3) it isvery small in size_
The specimens from the Arctic deep-sea sediments are thus apparently closely related toGlezer's forma from the Urals (but, according toher, from Eocene to early Oligocene). Judging
from her illustrations, however, the Russian
specimens seem to possess an apical plate (see83particularly her figures 16 of 1964 and 1966)
instead of thick lateral rods, and an apical bar
short if present.
Perhaps it would be advisable in the future
to remove the present taxon from D. carentis
because of the differences in the shape of basal
body ring (circular vs. square) and the natureof radial spines (short and thick vs. long andpointed). However, such action should wait until
an actual comparative study of Russian samples
can be made.

Dictyocha curta Ling, n. sp.
PI. 10, Figs. 18-21.

Description:-Basal body ring, square, withsmoothly rounded apical comers; radial spines
short, occasionally truncated at the distal end,
and located near the middle of the side, not at
the comers like other species; an apical bar, very
short, but parallel to a set of the basal ring;neither apical nor basal accessory spines present.
Derivation of name:-The species name isderived from curtus, Latin for short, referring to
the very short radial spines for the species.
Remarks:-This tiny Dictyocha is characterized by its square-shaped basal body ring, theunusual position of radial spines at the middle offour sides and not at the comers like numerous
other silicoflagellates, and a short apical bar
which is parallel to a pair of sides of basal bodyring.
Measurements:-Length of a side of basal
body ring, 15-22 Ilm; of basal spines, 1-4 Ilm.
Types:-Holotype, USNM 395823; Isotype,
USNM 395824.
Dictyocha deflandrei Frenguelli ex GIezer
PI. 10, Fig. 22;PI. 11, Figs. 1, 2.
Dictyocha deflandrei Frenguelli, 1940, figs. 14
a-d.
Dictyocha deiiandrei var. deflandrei (Frenguelli),
GIezer, 1966, p. 244, pI. 12, figs. 12, 16; pI.
3 '2, fig. 4.
D. d. var. compieta f. compieta Glezer, 1966,
pp. 244, 245, pI. 12, figs. 14, 15.

Hsin Y. LING

84

D. d. var. completa f. producta Glezer, 1966, pp.
245, 246, pI. 12, figs. 17-19.
Remarks:-A square-shaped basal ring withfour developed radial spines and an apical plate(but without window) characterize the species.
The three varieties and forma listed above from
Russia are here combined confirming them as
an intraspecific variation. Basal accessory spines
mayor may not be present.
Bukry observed triangular to hexagonal variants of the species from Legs 28 (1975a) and 29(1975b) DSDP samples from the southernoceans.
Dictyocha fibula Ehrenberg
PI. 11, Figs. 3·6.

Remarks:-As in my previous studies (e.g.,
Ling, 1970, 1972, 1973, 1975, 1977), a broad
species concept is applied for specimens whose
apical bar lies in the direction of major axis.
Radial spines are either short or long.
Dictyocha obliqua Glezer
PI. 11, Figs. 7,8.

Dictyocha obUqua Glezer, 1964, p. 57, pI. 2,
fig. 10; 1966, p. 246, pI. 13, figs. 1-5.

Remarks:-This tiny silicoflagellate showssome superficial resemblances to forms reported
from Late Eocene to Early Oligocene of Russia by
Jouse (1955, fide Loeblich, III., et al., 1968,
p.111, pI. 21, fig. 8), and by Glezer (1964, p. 53,
pI. 1, figs. 17, 18; 1966, p. 243, pI. 11, figs. 1720), but all the above Russian specimens show
circular basal body rings.
Intraspecific variations observed during thepresent examination are: (1) the shape of thebasal body ring; and (2) the proportion of thesize of the apical plate relative to the basal bodyring, as shown in the illustration. It should be
noted that, thus far, only the subspecies, D.
rotundata secta Glezer, has been reported fromoutside of Russia, i.e. the Norwegian Sea (Site343) by Bukry (1976b), Martini and Muller(1976, as D. rotundata Jouse), but not the typeof the species, D. rotundata Jouse (1955, 3a, fide
Loeblich, III, et al., op. cit; Glezer, 1964, p. 53,
pI. 1, figs. 17, 18; 1966, pI. 11, figs. 17-20).
Dictyocha spinosa Deflandre
PI. 11, Figs. 13, 14.

Corbisema spinosa Deflandre, 1950, p. 65/82,
figs. 178-182.
Dictyocha spinosa (Deflandre), Glezer, 1966, pp.
238,239, pI. 10, figs. 6-8.

Remarks:-Although there are some differences (such as the minor axis is less oblique
toward the major axis and an apical plate isalmost exclusively in the direction of the majoraxis), it is considered here that the present Arctic
forms are conspecific with those forms reported
from Late Eocene through Early Oligocene of
Russia observed by Glezer.

Remarks:-The specimens from the Arctic
agree well with those reported by Deflandre from
Barbados and Glezer from Russia. However, theArctic specimens are larger than those previously
reported specimens.

Dictyocha sp. cf. D. rotundata Jouse

PI. 11, Figs. 15, 16.

PI. 11, Figs. 9-12.

Dictyocha speculum Ehrenberg, 1838, p. 129,
pI. 4, fig. Xn.
Distephanus speculum (Ehrenberg), Haeckel,
1887, p. 1565.

Description:-A basal body ring, generallysmooth, semi-square to square without radial
spines; an apical plate nearly square connectedby short, broad lateral rods which originate fromthe corners of the basal ring; basal accessory
spines absent.

Genus Distephanus Stohr, 1880

Distephanus speculum (Ehrenberg)

Remarks:-Considering the well-known long
geological range and the widely accepted ecological habitat of cold-water forms (Gemeinhardt

795. Paleogene Silicoflagellates and Ebridians1930), it is somewhat surprising to find that only
a few specimens were encountered in the studied
submarine deposits from the Arctic Basin.
Order Stereotestales Lemmermann, 1901a
Genus Ammodochium Hovasse, 1932aAmmodochium fletcheri Ling, n. sp.
PI. 11, Figs. 17-20; PI. 13, Fig. 5.

Description:-Ovoidal in outline in dorsoventral view; three stout proclades brancheddistally to encircle one large and two small
laterally situated upper windows; a small apicalring; proclades broadened distally to encircle a
median window; a continuation of opisthoclades,slightly more slender than proclades, also stout
and branched distally to encircle three lower
windows like an apical end.
An examination by scanning electron microscope revealed that the entire surface of thespecimen is covered by small open cavities
providing a rugged appearance for the margin ofskeletal components (PI. 13, Fig. 5).
Derivation of name:-The species is named
after the Fletcher T -3 Ice Island where theanalyzed sediment core was collected. The namealso refers to Joe O. Fletcher, currently at
the NOAA, honoring his contribution to Arctic
climatology .
Remarks:-This new species shows someresemblance to A. speciosum Deflandre (1934,
pp. 92-94, figs. 37,38) reported from diatomitesof Skive (Jutland), Denmark, and from submarine deposits of DSDP Site 277 (52°12.43'S;
116°11.48'E) of the southern Campbell Plateauof the subantarctic southeast Pacific (PerchNielsen, 1975b, p. 880, pI. 5, figs. 1, 2). This
species is, however, distinctly different fromthem by: (a) the more ovoidal outline; (2) having
only one median window instead of two, resulting in the absence of mesoclades; and (3)possessing two extra lateral small windows at theapical and antapical ends.
Measurements:-Length 28-36 Mm; width, 2430Mm.
Types:-Holotype, USNM 392825; Isotype,85

USNM 392826.
Ammodochium rectangulare (Schulz)
PI. 11, Figs. 21-23.

Ebria antiqua var. rectangularis Schulz, 1928,
p. 274, figs. 72 a-d.

Ammodochium rectangulare (Schulz), Deflandre,
1932, pp. 303-305, figs. 1-13; Ling, 1971,
p. 694, pI. 2, figs. 6, 7.

Genus Ebriopsis Hovasse, 1932a
Ebriopsis cornuta Dumitrica and Perch-Nielsen
PI. 11, Fig. 24; PI. 13, Fig. 4.

Ebriopsis cornuta Dumitrica and Perch-Nielsen,
in Perch-Nielsen, 1975b, p. 880, fig. 2, pI. 7,
figs. 8, 9.

Remarks:-The present taxon seems to agree
well with those observed by Perch-Nielsen fromthe subantarctic southwest Pacific (1975b) andthe Norwegian Sea (1976b).
The surface microstructure on the skeletalcomponents is shown in the scanning electron
micrograph (pI. 13, Fig. 4). Note that the small
cavities are scattered over the surface of theskeletons.
Genus Pseudammodochium Hovasse, 1932b
Pseudammodochium dictyoides Hovasse
PI. 11, Figs. 25-27.

Pseudammodochium dictyoides Hovasse, 1932b,
pI. 463, figs. 12-15.

Discussion(A) Microfloral comparison and age assignments
Table 1 presents the geological occurrence ofsilicoflagellate and ebridian taxa observed fromthe core 422 sediments of the Alpha Ridge.
These taxa are also illustrated in Plates 10-13.
The uniqueness of the assemblage is apparent
when a comparison is attempted with all thepreviously published records of this group ofsiliceous microfossils worldwide: (1) completely
absent are the age diagnostic forms of either

86

Hsin Y. LING

Cretaceous or those of well-known forms of late
Late Plaeocene or younger age, and (2) a few
siliceous microfossils show some resemblance
only with those taxa reported previously from
Paleocene outcrops of USSR.
The silicoflagellate composition of Late
Cretaceous age has been well documented indetail (Hanna, 1928; Mandra, 1968; Ling, 1972),
including the nearby FL-437 core from the
Arctic (Ling et aZ., 1973; Bukry, 1981a), andSites 208, 216 and 275 of Legs 21, 22 and 29
respectively (Bukry, 1973, 1974, 1975b) of the
Deep Sea Drilling Project from the southernhemisphere. None of theese age diagnostic species
were encountered from the core 422 materials.
On the other hand, the conspicuous complete
absence of specimens belonging to the genera
NavicuZopsis and Mesocena from the core 422 israther striking and warrants further discussion.
Both of these two genera are characteristic
and/or abundant for upper Upper Paleocene andyounger sediments although Glezer (1966,

p. 163) reported Mesocena aff. apicuZata (Schulz)
from Early Paleocene of Ural) (e.g., Glezer,
1966; Bukry, 1981b; Ling, 1981).
Numerous articles have been published fromboth the n.orthern and southern hemispheres
including areas as far north as Russia (Glezer,1966) and Denmark (Perch-Nielsen, 1976a) andas far south as the subantarctic regions (Busen
and Wise, 1976; Ling, 1981). Consequently,
noting the complete absence of these two genera
from the core 422, it appears safe to conclude
that: (1) their absence is probably not due topaleogeographic limitation, and (2) the age ofthe cored sediments is Early Paleogene, probably
predates late Late Paleocene.
Once the above age assignment has been
established, it is not surprising that the Late
Cretaceous core FL-437 shows only normal
polarity (Clark, 1971), because the majority of
the Cretaceous Period has been known to havenormal magnetic polarity (van Hinte, 1976).
On the other hand, throughout the Early

Explanation of Plate 10
Scale bar = 10 ",m. Upper left bar for figures 1-6, 8-11; lower left bar for figures 7, 16-22.
Location of specimen is indicated as: sample no., slide no., England Finder reading.
Corbisema apicu/ata (Lemmermann)
Figs. 1, 2.
1. 21, L-2, U21/0; 2. 16, R-1, D15/0, abapical lateral view showing the nature of abapicalaccessory spines.
Corbisema hastata hastata (Lemmermann)
Figs. 3,4.
10, R-1, F20/3.
Figs. 5, 6. Corbisema sp. cf. C. inermis minor (Glazer)
5, L-2, 019/0.
Fig. 7.
Corbisema triacantha (Ehrenberg)
20, L-2, T39/2.
Figs. 8-11. Dictyocha sp.
8,9. 18, R-1, U23/0, 10, 11. 19, R-1, V24/0.
Figs. 12-15. Dictyocha arctios Ling, n. sp.
12,13. 1, R-1, F15/0, Holotype U.S.N.M. No. 395821.
14,15. 2, L-3, M21/0, Isotype U.S.N.M. No. 395822.
Figs. 16, 17. Dictyocha sp. cf. D. carentis incerta (Glezer)
10, L-2, D17/3.
Figs. 18-21. Dictyocha curta Ling, n. sp.
18,19. 8, L-2, L41/0, Holotype U.S.N.M. No. 395823.
20, 21. 1, L-2, F10/0, Isotype U.S.N.M. No. 395824.
Fig. 22.
Dictyocha deflandrei Frenguelli ex Glezer
20, L-2, Q24/0.

Plate 10

LING: Early Paleogene Silic o flagellates

6

5

-

2

4

3

7

8

9

10

11

12

-

13

.'8 m ~
19

16

•

17

20

~/2'

22

15

795. Paleogene Silicoflagellates and Ebridians

Table 1. Occurrence of silicoflagellates andebridians (based on 300 specimen count)from FL-422 cored sediments of the Alpha
Cordillera region of the Arctic Ocean, (P,single specimens; R, 2-5%; C, 6-25%; A, >
26%).

~
~
~

I

I

~

I
I I

~
~­

I

~
~

I

~
~

~
~
~

r---!--!-

~

I I
I I

I

I

I I~ I

,

I I

~

~

t-Z-

,

~
~

II

~

rrnJ iI~~
1

I

Paleogene interval, the magnetic polarity of thenormal-reversed combmation has been repeatedseveral times (Hardenbol and Berggren, 1978).
Therefore it is plausible that the Paleocene FL422 core contains a short normal-reversed normal
polarity record within the COre (Clark, 1974).
Exactly to which normal-reversed combination
the core 422 under discussion will correlatecannot be determined at this time.
Before leaving the subject of the geologicaloccurrence and age determination of the FL-422
assemblage, a short discussion should be added

87

here. Some perplexing problems are posed byoccurrences of several species in the Alpha Ridge
sediments whose geological ranges have beenreported only from Late Eocene and Oligocene
from the Soviet Union. It is possible that thesesilicoflagellates and ebridians are reworked orcontaminated; nevertheless, the complete absence of Mesocena and Naviculopsis species in
the present assemblage seems to refute such a
possibility. Thus the only plausible explanation,
at least for the time being, is that the assemblage
recovered from the FL-422 is genuine and thatthese taxa recovered actually made their initialgeological appearance as early as during Early
Paleogene time in this part of the world.
(B) Significance to tectonic history of Arctic
Ocean
In spite of their characteristic microfloral
compositions and their occurrences from the
Arctic Ocean, it has been difficult to conceivethat these Late Mesozoic (FL-437) and Early
Cenozoic (FL-422) cored sediments were sandwiched both above and below by foraminiferabearing Pleistocene deposits. Therefore, unlessadditional occurrence of these sediments on theAlpha Ridge or geophysical data of the area canbe substantiated, the positve confirmation as tothe source of the sediments from the Alpha
Ridge would remain mere speculation.
The resul ts of the seismic profile of the area
obtained from the Ice-Island reveal that theAlpha Ridge is one of the largest submarine
features in the Arctic Ocean (Hall, 1970, 1979).
Instead of jagged arcuate zones, which typify thewell-known mid-oceanic ridges, it is rather a flattop feature dipping toward the south. The
Cretaceous FL-437 core was recovered on theflank of a faulted graben-like structure immediately north of the northern end of the Alpha
Ridge's highest edge (Text-fig. 2). There is no
discernible sediment cover over this graben
structure, suggesting that it was formed comparatively recently, probably in the Late Pleistocene
at the same time that the material in core 437
was slumped. On the other hand, the Late Paleogene core 422 was raised from the southernfoothill of the Ridge (Hall, 1979), the likely

88

Hsin Y. LING

place where such slumping would take place(Text-fig. 2). Thus, although these two cores are
slumped materials, it is highly likely that theirsource can be traced back to the nearby crestal
area of Alpha Ridge.
Perhaps it is a lucky coincidence that thesetwo cores are located on the opposite flanks of
the Alpha Ridge, but the location of the Early
Paleogene core is farther away from the "Apparent axis" of the (Alpha) Ridge than that of
Cretaceous age. While it is rather tempting toapply the age versus distance relationship toverify the sea-floor spreading hypothesis for thearea, this author believes that this jUdgements isstill premature because it relies on merely twocores of different ages to evaluate whether Alpha
Ridge was the dormant axis of early Cenozoic
spreading center in the Arctic (Vogt and Ostenso,
1970, Hall, 1970, 1979) or not (Vogt et al.,1979).
(C) Significance to paleooceanography of Arctic
Ocean

The finding of siliceous microfossils fromcores FL-422 and -437 is significant to the consideration of paleooceanography of the Arctic
Ocean. Silicoflagellates are widely recognized as agroup of phytoplankton of the normal marine
habitat (e.g., Marshall, 1934, Gemeinhardt,
1930), and such interpretation has been substantiated by laboratory experiment (Van Val kenburg and Norris, 1970). Thus it is safe to assume
that the submarine deposits containing abundantsilicoflagellate specimens were deposited during
the normal marine environment. The ages of two
pre-Pliocene cores from the Arctic Basin are
fortunately identified as one from the Latest
Cretaceous and the other Early Paleogene;that is, from both above and below the Cretaceous-Tertiary boundary.
The massive extinction of the organic world at
the end of the Mesozoic has been well known toearth scientists and numerous hypotheses havebeen brought forward attempting to account forthis unusual event (see Alvarez et ell., 1980). One

Explanation of Plate 11
Scale bar = 10 /lm. Upper left bar for figures, 1, 2, 9-12, 25, 26; upper right bar for figures 3-8,
13-16; bottom bar for figures 17-24.
Figs. 1, 2.
Dictyocha deflandrei Frenguelli
22, R-l, N24/0.
Figs. 3-6. Dictyocha fibula Ehrenberg
3,4. 4, R-l, H28/0; 5,6. 8, R-l, P34/1.
Figs. 7, 8.
Dictyocha ob/iqua Glezer
16, L-2, L39/I.
Figs. 9-12. Dictyocha sp. cf. D. rotundata Jouse
9,10. 9,L-2,JI8/1;11,12. 23,L-2,027/0.
Figs. 13, 14. Dictyocha spinosa Deflandre
22, R-l, N23/4.
Figs. 15, 16. Distephanus speculum (Ehrenberg)
9, L-2, N25/3.
Figs. 17-20. Ammodochium fletcheri Ling, n. sp.
17,18. 3, L-2, TI7/0; Holotype U.S.N.M. No. 395825.
19,20. 21, L-3, U40/0;Isotype U.S.N.M. No. 395826.
Figs. 21-23. Ammodochium rectangulare (Schulz)
21, 22. 17, L-2, EI4/4; 23. 16, L-2, C26/3.
Fig. 24. Ebriopsis cornuta Dumitrica and Perch-Nielsen
8, R-l, E26/4.
Figs. 25-27. Pseudammodochium dictyoides Hovasse
25,26. 22, L-2, R23/4; 27. 22, L-2, W29/2.

LING: Early Paleogene Silicoflagellates-

Plate 11

2

-

3

4

• D ~~
9

8

8

7

10

®

5

6

12

11

21

13

14

15

* l1
16

22

Ir.~

.,..

r~ ~~~I i

.u

(~ J

::""'I'"...., .,.

I.

18

17

24

-

19

20
23

795. Paleogene Silicoflagellates and Ebridians

- --

D

SDkm

Text-fig. 2. Seismic reflection profiles of
Alpha Cordillera in the vicinity of pre-Miocene
cores FL-422 and FL-437 (after Hall, 1970,1979). The position of the "apparent axis" (Hall,1970) is marked by an inverted triangle.

of the most interesLing and recent views has
been expressed by Gartner and Keany (1978),
Thierstein and Berger (1978) and Bukry (1981a).
They suggest that the presence of low salinity
surface water in the Arctic Ocean for a very
short time - approximately 10,000 years - was
responsible for the "terminal event." This view
was already commented upon by Clark andKitchell (1979) and Kitchell and Clark (1982).
The resolution of silicoflagellate zonation is
not precise enough at the present time to datethe effect of such a short geological phenomenon. However, the continuous occurrence ofCretaceous silicoflagellates in the Early Paleogene
has been reported from Russia (Glezer, 1966),
from the Tasman Sea (DSDP Site 208) and theIndian Ocean (Sites 214 and 216) (Bukry, 1973,
1981b). This implies that at least some Cretaceous silicoflagellate taxa did successfully survive
through the boundary crisis and that a normal
marine paleoenvironment was present at least
during these times in these areas. The finding of89

the present two silicoflagellate-bearing coredsediments from both sides of the boundary
further substantiates the existence of normal
marine conditions in the Arctic Ocean during
these intervals.
According to Thierstein and Okada (1979),
based on the analyses of closely spaced samplesof every two cm interval across the boundary at
DSDP Site 384 in the western North Atlantic,
the Mesozoic calrareous nannofossil taxa aregradually replaced by Tertiary forms in the"apparent" continuous deep-sea sediments.
On the other hand, a sharp drop of both (j 18 0
and (j 13 C values at the terminal event has been
observed in samples from the DSDP Site 356 of
the western South Atlantic (Thierstein andBerger, 1978). They consider the "repeatedisolation and opening of the Arctic which led torepeated injection of freshwater" as one of themechanisms accounting for the rapid fluctuationsin isotopic value.
It is neither within the scope of this paper nor
the intention of this author to become involved
further in this intriguing and important boundary
problem. Whatever the concluding hypothesis
will be, in order for anyone interpretation toprevail, even for a short duration, it should be
able to accomodate or explain all the conceivablequestions of geologic phenomena. In case ofsilicoflagellates and ebridians, it must be able toexplain at least (1) how marine conditions werereestablished after the sudden, rapid extinctionof some biota, and at the same time (2) the continuous survival of some Cretaceous forms invarious parts of the world.
Acknowledgments
The core sediments upon which the present
investigation was based were collected originallyby Arthur Lachenbruch and Vaughn Marchall,
U.S. Geological Survey (Menlo Park), and werelater provided by David L. Clark, University of
Wisconsin-Madison. As in the previous investigation of Core FL-437, the documentation of prePliocene silicoflagellates and ebridians from the
Arctic Ocean bottom could never have takenplace without their kind assistance.

Hsin Y. LING

90

The critical review by Drs. Katharina PerchNielsen (Switzerland) and John F. Sweeney(Canada) greatly facilitated the final preparationof the manuscript. This research was supported
in part by NSF grant (DPP 79-11304).
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Deflandre, G. (1932): Remarques sur quelques

Explanation of Plate 12
All the illustrations were photographed with a scanning electron microscope. Scale bar = 5 /lm.
Fig. 1.
Corbisema triacantha (Ehrenberg)
Abapical view showing the nature of basal accessory spines and surface microstructure on thebasal body ring. Note here that the surface microstructure is also on the abapical side.
Figs. 2"'-4. Dictyocha sp.
2. Abapical view showing surface microstructure on all the skeletal components.
3. A part of a specimen of figure 2 showing the details of surface microstructure of basal
body ring and a radial spine.
4. Apical view showing surface microstructure on an apical bar and lateral rods.

LING: Early Paleogene Silicoflagellates

Plate 12

795. Paleogene Silicoflagellates and Ebridians
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--(1979): Sediment waves and other evidence

91

of paleobottom currents at two locationsin the deep Arctic Ocean. Sediment. Geol.,
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Tecnoscienza.

92

Hsin Y. LING--(1972): Upper Cretaceous and Cenozoic
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All the illustrations were photographed with a scanning electron microscope. Scale bar = 5 ILm for
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Figs. 1-3. Dictyocha sp. cf. D. carentis incerta (Glezer)
1. An apical view showing the microstructure of the skeletal components.
2. An apical view showing microstructure of skeletal components.
3. The detail of surface microstructure of lateral rods and an apical bar.
Fig. 4. Ebriopsis cornuta Dumitrica and Perch-Nielsen
Fig. 5. Ammodochium fletcheri Ling~ n. sp.

LING : Early Paleogene Silicoflagellates

Plate 134

5

795. Paleogene Silicoflagellates and Ebridians
Tripoli von Grotte Provinz Girgenti in
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The growth and morphology of the silicoflagellate Dictyocha fibula Ehrenberg in

93

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(ed.), Marine geology and oceanography of
the Arctic Seas: p. 83-117. Springer-Verlag,Inc.
- - and Ostenso, N.A. (1970): Magnetic andgravity profiles across the Alpha Cordillera
and their relations to Arctic sea-floor spreading. Jour. Geophys. Res., vol. 75, no. 26,
p. 4925-4937.
- - , Taylor, P.T., Kovacs, L.C. and Johnson,
G.L. (1979): Detailed aeromagnetic investigation of the Arctic Basin. Ibid., vol. 84, no.
B3, p. 1071-1089.
Zanon, V. (1934): Silicoflagellate fossili italiane.
Acta Pont. Acad. Sci. Nov. Lincei, vol. 87,
p.40-82.

~ • • E~~.W~hk~.~e~Mm.~~.t~~Y7.W.:~ • • ~7~77.
Jii;t.lt!!~-C:·iJfE*,Il1; (T-3).J: I) 4*JlXU.::z7 (FL-422) I:t., fE.~B.t~7'Y 7.1;:'°t.ltJ'Ii •• ~~ft~~~~, • • ~~.~EW.~~, ~~~~~~.~e~.AAt~~~~~~~t
Y~hh ~o ~ L -C.::. ~.Ej;jtfJ!~':t., I~H;:.*11f ~ht.:~JtJj(~jilli*c~:z 7 (FL-327) .ItllfJ{4o/.J t ~K, ~~.EKt*~~~M~ •• .Itll.4o/.J~~~~~.~~~E~~~~~~~ ~•• ~~~1f;.se, o-\"-C':t.8iJli:*c-.~*c (K-T) ~mw.r.nWi~7f~~J:~~.lfi:t.(I£lf*,~~,j;~o#t-tt-C Dictyocha arctios, D. curta, Ammodochium fletcheri ~ 3 ~~~ L <~G,fiJ(**,' Lt.:of-t.: fri'-Trans. Proc. Palaeont. Soc. Japan, N. S., No. 138, pp. 94-110, pIs. 14-16, July 15, 1985

796. A MIDDLE DEVONIAN TRILOBITE FAUNAFROM THE KITAKAMI MOUNTAINS, NORTHEAST JAPAN- II. THE CALYMENIDAE*
ATSUSHI KANEKO
15-7 , Fukae-honmachi 1-chome, Higashinada-ku, Kobe 658, Japan

Abstract.
This is part 2 of serial papers of the Middle Devonian (probably
Eifelian) trilobite fauna from the Nakazato Formation in Northeast Honshu,
Japan.
A calymenid genus Nipponocalymene, gen. nov. and its type-species Nipponocalymene hamadai, gen. et sp. nov. are proposed in this part.

the glabella of the paratype B cephalo-thorax(PI. 16, Figs. la-c) in the same slab as theparatype pygidium of Nipponarges mediosulcatus(Part 1, pI. 87, figs. 2a-d) and to excavate forthe taking of a cast from the external mould.
The author is now convinced that the aberrant
characters seen on the hypostomes of the newJapanese caly'menid are original in natureand never attributable to a particular state ofpreservation.
These are chiefly used to separate Nipponocalymene from Calymene at the generic level.

Introduction
A newly discovered calymenid from thepresent trilobite fauna clearly demonstrates thepapillate butress structure at the 2p lateralglabellar lobe on the cranidium, a character
diagnostic of the subfamily Calymeninae in the
restricted sense of Siveter (1977). At first glance,
the dorsal exoskeleton of the Japanese form
appears to fall into the genus Calymene Brongniart, 1822, but the hypostome of the holotype
specimen (PI. 14, Figs. If-l) shows completely
exclusive characters, the main one being a pairof protuberances on the median body. It wasnecessary to determine whether or not they are
original in nature. Fortunately the author has
obtained very kind co-operation from Yoshiaki Okamura of the Sekishin-kan Museum,
Kusatsu City, Shiga Prefecture and radiographically searched for hypostomes in the available
samples retaining the cephalic regions. As aresult, we have succeeded in discovering an
additional hypostome lodged directly below

Systematic palaeontology
Family Calymenidae Burmeister, 1843
Subfamily Calymeninae Burmeister, 1843
Genus Nipponocalymene Kaneko, gen. nov.
Derivation of name:-Nippon, Japan + typicalgenus Calymene Brongniart, 1822.
Type-species:-Nipponocalymene
hamadai
Kaneko, gen. et sp. nov. from the Middle
Devonian (probably EifeUan) Nakazato Formation in the southern part of the Kitakami Mountains, northeastern Japan.
Species assigned:-Presently only the, type-*Received March 31,1984.
*J.T.A.F. (Studies on Japanese Trilobites andAssociated Fossils) contrib. no. 38.
94

796. A Middle Devonian Trilobite Fauna

species is known.
Generic diagnosis:-Papillate.butressed ca·
lymenid with unusual hypos tome characterized
by median body with no distinct median furrow,anteriorly very strongly inflated main part ofmedian body homologous with anterior lobe ofusual calymenid pattern with a pair of protuber.
ances directed ventro-Iaterally and anteriorly
from ventro-Iateral sides of its most raised portion and symmetrically arranged with regard tosagittal line, by considerably shortened (sag. andexsag.) crescentic-shaped remainder of medianbody homologous with posterior lobe sloping
away steeply posteriorly and by prominent,
somewhat pointed macula situated near posterolateral comer of median body. Glabella bellshaped in outline, with three pairs of lateralglabellar lobes. Anterior border rolled, convex.
Preglabellar furrow relatively short (sag. andexsag.). Palpebral lobe opposite 2p lateral glabellar lobe.
Thorax of thirteen segments:
Pygidial axis almost reaching pygidial extremity. Pleural furrow deeply incised, runningon to border roll; no modification of fifth
pleural furrow. Interpleural furrow absent.
Ventral portion of pygidial border roll narrow·(sag. and trans.). Very large, elongate oval, somewhat blister-like tubercles on posterior-most faceof glabella along occipital furrow; posterior
cephalic border, occipital ring, thorax andpygidium except its granulate ventral face with
scattered pits; hypostome apparently smooth;rest of body tuberculate and/or granulate.
Distribution:-Confined to the Nakazato
Formation in Northeast Honshu, Japan.
Discussion:-Whittington (1956, pp. 170171) pointed out four subtypes of the hypostomes to form one of the main bases offour corresponding subfamilies in the family
Odontopleuridae.
As for the Calymenidae, Whittington (1971b,
p. 455) suggested that "certain taxonomic
characters such as the outline and the presenceor absence of the raised area on the medianbody of the hypostome may prove to be ofvalue in generic and in higher subdivisions such95

as Shirley's groups A and B".
Siveter (1977, p. 353) proposed the subfamily Calymeninae to be limited to Shirley's
group B, characterized by the presence of thepapillate butress structure and a new subfamilyname Flexicalymeninae for Shirley's group A
characterized by the absence of the papillate
butress structure, and noted that "In the present
state of knowledge the hypostome also separates
these two subfamilies. Contrary to that of thegenerally later calymenines, all known flexicalymenine hypostomes do not have a discreteraised area or protuberance on the anteriorlobe". But he suggested Metacalymene may be
an exception to this rule. Later he (Siveter,
1979) described and illustrated isolated calymenid hypostomes with raised area from the
Silurian Kopanina Formation at Kosovo inBohemia as ?Metacalymene baylei (Barrande,1846) rather than as Calymene tenera Barrande,
1852 which co-occurs with it and has the papillate butress structure and suggested that his
subfamilial diagnosis would require appropriate
amendment if the assignment of the hypostomes
to the papillate-butress-free genus Metacalymene
was proved.
Recently Price (1982) indicated that thehypostomal protuberances are not restricted
to the papillate-butressed genera of the subfamily
Calymeninae because isolated hypos tomes assigned to Gravicalymene quadrata (King, 1923)
and Gravicalymene arcuata Price, 1982 from the
Ashgillian of North Wales, Great Britain havedistinct protuberances.
In addition the anterior lobe of the medianbody of the hypos tome is never flattened centrally in such species without papillate butressstructures as Flexicalymene (F.) sp. ex. aff.
onniensis described by Haas (1968, text-fig.
17c, pI. 29, fig. 3) from the upper Llandoverian
to lower Wenlockian of Northwest Turkey,
Gravicalymene quadrilobata Chatterton, 1971
(pI. 19, figs. llA, B, pI. 20, figs. 2A, B, 3A, B)
from the Emsian of Australia, Apocalymene
coppinsensis Chatterton & Campbell, 1980
(pI. 8, figs. 3, 5, 13) from the Wenlockian ofAustralia and Gravicalymene eunoa Haas, 1968

96

Atsushi KANEKO(text-fig. 18c, pI. 29, figs. 13-14) from thelower Emsian of Northwest Turkey; the former
three show indistinct, gentle axial ridges andthe last one shows an indistinct, flat cone-shaped
central swelling. Chatterton and Campbell (1980)
have regarded the species quadrilobata andeunoa to be congeneric with their new species
Apocalymene coppinsensis, the type-species of
their new genus Apocalymene, which they haveconsidered to have a style of enrollment in common with Calymene with discrete, prominent
protuberance on the anterior lobe of the medianbody of the hypostome.
In the family Calymenidae all known discrete
protuberances and indistinct ridges or swellingson the anterior lobes of the median bodies of thehypostomes are single and situated on the sagittalline [see Calymene blumenbachii Brongniart,
1822 (Whittington in Moore (ed.) 1959, fig. 359,
1c) from the Wenlockian of Britain; Calymene
lawsoni Shirley, 1962 (Haas, 1968, text-fig. 16f,
Siveter, 1983, pI. 7, figs. 12-13, 16) from the
Ludlovian of Britain; Calymene puellaris Reed,
1920 (Siveter, 1983, pI. 10, fig. 12) and C. cf.
puellaris Reed, 1920 (ibid., pI. 10, fig. 17) fromthe Ludlovian of Britain; Calymene pompeckji
Kummerow, 1928 (Schrank, 1970, pI. 2, fig. 7)
from the Silurian erratics of north Germany;
Calymene neointermedia R. & E. Richter, 1956
(Lindstrom, 1901, pI. 3, figs. 6-7, Haas, 1968,
text-fig. 16d) from the Ludlovian of Gotland(see Siveter, 1983, pp. 75-78); Calymene interject vaneki Pillet, 1968 (pI. D, fig. 4) from theLower Devonian of Bohemia; Calymene arotia
Haas, 1968 (text-fig. 16b, pI. 29, figs. 6-7)
from the upper Ludlovian of Northwest Turkey;
Calymene antigonishensis McLearn, 1924 (pI.
26, figs. 7-8) from the Wenlockian and Downtoni an of Nova Scotia; Calymene platys Green,
1832 (Hall and Clarke, 1888, pI. 1, figs. 7-8)
from the Emsian (Schoharie Formation) of New
York, U.S.A., Calymene clavicular Campbell,
1967 (pI. 10, figs. 1-7,13-15) from the upper
Wenlockian to lower Ludlovian of Oklahoma,
U_S.A.; Calymene (s.1.) subdiademata McCoy,
1851 (McNamara, 1979, pI. 9, fig. 16) fromthe Ashgillian of Britain; Calymene (s.1.) cf'

marginata (Shirley, 1936) (Ingham, 1977, pI. 21,
fig. 22) from the Ashgillian of Britain; Tapinocalymene nodulosa (Shirley, 1933) (Siveter,
1980, pI. 97, fig. 6) from the upper Wenlockianof Britain; Tapinocalymene vulpecula Siveter,
1980 (pI. 100, fig. 15) from the upper Wenlockian of Britain; Tapinocalymene volsoriforma
Siveter, 1980 (pI. 99, fig. 8) from the lower
Wenlockian of Britain; hypostomes illustrated as
Calymene tuberculata Brilnnich, 1781 (seeShirley, 1933, pp. 52-53, 62) by Angelin (1854,
pI. 19, figs. 5b, c), by Lindstrom (1901, pI. 3,
figs. 8-9) and by Fr. Schmidt (1907, pI. 3, fig.
1a)] .
So it is quite unexpected that the hypostome
attached to the dorsal exoskeleton which remains
analogous to that of the genus Calymene Brongniart, 1822 bears a pair of protuberancesarranged symmetrically with regard to thesagittal line on the main part of the medianbody homologous with anterior lobe of usualcalymenid pattern.
Most calymenid genera have been defined
mainly on such characters of the dorsal exoskeleton as the presence or absence of the
fixigenal butresses, the shape of the glabella
and the form of the anterior border, but neveron the characters of the sternites except the
rostral plate, of which border sector tends tobe modified according to the anterior border, forexample, in Spathacalymene Tillman, 1960.
The hypostome is a sternite preoral in position and may have formed a part of feedingmechanism and served as an anchor and a protection for the soft parts consisting of such digestiveorgans as the esophagus and stomach or proventriculum lodged below the anterior part of
the glabella (see Whittington, 1941, p. 521).
Thus this sternite should be considered of noless significance than the cephalon, especiallythe glabella lying vertically above it as an integumental organ.
In papillate-butressed genera of the subfamily
Calymeninae significant differences have notpreviously been recognized among known
hypostomes (see Whittington, 1971b, pp. 458,
463). This may possibly be a reflection of

796. A Middle Devonian Trilobite Fauna

conservatism in feeding habit of this trilobitegroup.
Therefore, the presence of completely exclusive characters of such a vital organ in amember of the subfamily Calymeninae should begiven more weight in classification than suchmodifications of the anterior border as "ridging"
and a spatulate process, which are used essentially as single characters of generic importanceto distinguish Diacalymene (Middle Ordovician
to Middle Silurian) and Spathacalymene
Tillman, 1960 (Upper Silurian) from Calymene respectively, but are now generally
considered to be primarily adaptive in nature(see Whittington, 1981b, p. 459). Temple(1975) has questioned the taxonomic importanceof the "ridging" of the anterior border in thefamily Calymenidae. Ingham (1977) andMcNamara (1980) have accepted his view, but
Siveter (1980) and Holloway (1980) have not.
Siveter (1980, p. 796) pointed out the evolution
on the preglabellar area of Spathacalymene
from that of "Calymene" vogdesi Foerste, which
has been regarded as a Diacalymene species by
Holloway (1980, p. 58), or similar species would
require only the lenthening of the anteriorborder and this morphological change to bemuch less than that within his new genus Tapinocalymene, in which the form of the anteriorborder was used only for specific discrimination.
In Papillicalymene Shirley, 1936 (the upper
Silurian) the anterior border, which is strongly
upcurved (Whittington, 1971a, p. 131, figs. leg, 1971b, pp. 463-470, pIs. 85-86), is notessentially different from that in Calymene.
Judging by the position of the papillate 3p andfrontal glabellar lobes and corresponding genal
butresses, characters diagnostic of Papil/icalymene, it seems likely that they are moreclosely related to the ventral appendages thanthe digestive organs, but there seems to be noreason to draw a distinction of taxonomic value
between characters· shown on the dorsal andventral integuments covering the anterior partof the cephalic region.
Schrank (1970, pp. 115-116, 138-141)
has not used the form of the anterior border to97

define the genus Calymene because of theconsiderable variation of this feature withinthat genus itself, but has used mainly this feature
to classify that genus into six species groups.
The cephalon of Nipponocalymene hamadai
is very closely comparable to those of the representatives of Schrank's third species group,
the tentaculata group, in the form of the anteriorborder and in the shape of the glabella. The
former differs from the latter by somewhat
shorter (sag. and exsag.) preglabellar fu"rrowand by rather more coarse tubercles on theglabella. The tentaculata group of the genus
Calymene consists of the following species;
Calymene tentaculata (Schlotheim, 1820) (=C. beyeri R. & E. Richter, 1956) from theK6bbingh1iuser Formation of Middle Ludlovian
age in Ebbe-Sattels in Rheinland, Germany andfrom a glacial boulder of equivalent "Beyrichienkalk"; C. antigonishensis McLearn, 1924 from
the Moydart and Stonehouse Formations of
Wenlock and Downton (Pridoli) age at Arisaig,
Nova Scotia; C. planicurvata Shirley, 1936 fromthe Upper (Shirley, 1936, p. 412) or ?Middle(Temple, 1975, p. 139) Llandoverian at Bog
Mine in Shelve in Shropshire, Britain; C. ohhesaarensis Fr. Schmidt, 1894 (= C. conspiqua
Fr. Schmidt, 1894?, see Schrank, 1970, p. 140)
from the Silurian (K stage) at Ohhesaarepank
in Osel, Estonia; C. weberi Maximova, 1968
from the Upper Silurian (S2) Kockbaital andLower Devonian (D 1) Pribalkhas horizons incentral Kazakhstan; C. aff. weberi Maximova,
1968 from the Kockbaital horizon; C. kokbaitalensis Maximova, 1968 from the Pribalkhas
horizon; Calymene sp. by Maximova (1968)
from the Kockbaital horizon; C. killarensis
Gill, 1945 from the Lower Devonian YeringianSeries at Killara in Victoria, Australia.
Hypostomes of the species within the tentaculata group have never known except for thatof Calymene antigonishensis, which was suggested to be possibly conspecific with typical
species C. tentaculata by Schrank (1970, pp.
139-140). Through the kindness of Dr. M. J.
Copeland of Geological Survey of Canada theauthor obtained a rubber cast and mould of the98

Atsushi KANEKO

paratype hypostome (GSC No. 5590) of C.
an tigonishensis, which had been illustrated on
figure 7 of McLearn's (1924) plate 26, andhas been able to make a comparison between
those of these calymenid species whose caphala
are comparable with each other.
The hypos tome of Calymene antigonishensis,
which is figured here for comparison (PI. 14,
Figs. 5a--c) , is of usual calymenid pattern
showing the following features: the medianbody is moderately inflated and is divided by
the median furrow into two lobes; the anterior
lobe bears a single, central protuberance directed
only ventrally (though the specimen figured
here shows only its stump) and is somewhat
wider (trans.), much longer (sag. and exsag.),more convex than the posterior lobe; the posterior lobe is somewhat shorter (sag. and exsag.)than those on most of the other known hypostomes of Calymene species; the medianfurrow is weakly incised through its wholecourse and runs postero-adaxially from thelateral border furrow to the maculae, aroundwhich it is represented by maculate furrows
and between which represented by a somewhat broad (sag.) depression; the macula isslightly convex and situated more anteriorly
than the posterior wing.
As opposed to this, the hypostome of
Nipponocalymene hamadai shows the following
features unusual for calymenids: the medianbody is much more strongly expanded anteriorly
and divided by no distinct median furrow; themain part of the median body homologous
with the anterior lobe of usual calymenid pattern
is much longer (sag. and exsag.) and more convex(sag. and trans.) than the anterior lobe of themedian body of the former and is very strongly
inflated anteriorly and bears a pair of symmetrically arranged protuberances directed ventrolaterally and anteriorly from the ventrolateralsides of its most raised portion; the macula issituated near the posterolateral corner of themedian body and further backward than theposterior wing, so that the remainder, homologous with the posterior lobe of usual calymenid
pattern, is considerably reduced; the macula

is not defined by a maculate furrow but prominent and somewhat pointed.
The comparison between the above-mentioned two hypostomes seems to indicate clearly
that the extreme development of the anterior
lobe of the median body brought about suchchanges in morphology from Calymene to
Nipponocalymene as the bifurcation of theraised area (= protuberance) not to preventthe animal from enrolling as fully as possible
but to preserve a balance, the effacement of themedian (maculate) furrow and the considerable
backward transfer of the maculate. The excessive
development of the anterior lobe of the medianbody still appears to influence the style ofenrollment despite the bifurcation of the raised
area.
According to Chatterton and Campbell(1980, pp. 94-96), Calymene has a capacityof enrolling the posterior part of the thorax toa great degree and such correlative featureswith this as a tendency to keep the pygidial
extremity undeflected, a weak cincture at which
the pleural furrow are modified to fit against
the cephalic doublure during enrollment, apostaxial projection which is sharply delineatedlaterally by an expanded furrow resulting fromthe modification of the fifth (or sixth) pleuralfurrow and the adjacent interpleural furrow
and which fits into the deep narrow curvatureof the posterior edge of the rostral plate. Alsoin Calymene antigonishensis these characters
can be seen (see McLearn, 1924, pI. 26, figs. 5,
10).
By contrast, in Nipponocalymene, despite
having a capacity to enroll the posterior part of
the thorax as great as that of Calymene (PI. 14,
Fig. 1b, PI. 15, Fig. 10), no cincture can beobserved on the pygidial pleurae and the posterior end of the terminal piece of the axis
almost reaches the upwardly deflected pygidial
extremity and the fifth pleural furrow and rib
are never modified. These indicate that theouter part of the dorsal exoskeleton of thepygidium are never tucked inside the cephalicdoublure including the doublure sector of therostral plate, but the ventral part of the pygidial

796. A Middle Devonian Trilobite Fauna

border roll lies against the ventral part of the
cephalic border roll. In addition, the ventral
part of the pygidial border roll (PI. 15, Fig. 1p)
is much narrower (trans. and sag.) than that ofsuch species with a single but prominent protuberance as Calymene clavicula Campbell,
1967 (pI. 9, fig. 1, pI. 10, figs. 12-15). This
allows the animal to insert the raised area of
extreme width (trans.) resulting from the prominent bifurcation on the median body of thehypostome into the medial embayment in thepygidial doublure.
Of the other species of the tentaculata groupof the genus Calymene in which the pygidia
are known, C. weberi can be considered to havea hypos tome of ordinary type for that genus
because of the similarity to C. antigonishensis
in the pygidial morphology (see Maximova,
1968, pI. 9, figs. 5-6). In C. tentaculata, C.
kokbaitalensis and C. killarensis the postaxial
projection of the pygidium is relatively short(sag.), but appears to be delineated laterally
by a modified fifth pleural furrow, so that there
is little possibility of their hypostomes being
similar to that of Nipponocalymene hamadai(see Schrank, 1970, pI. 10, figs. 2, 3, 7, pI. 11,
fig. 7, pI. 12, fig. 4; R. and E. Richter, 1956,
pI. 2, figs. 18a, d, 23a, b, text-fig. 7; Maximova,
1968, pI. 8, figs. 2-4, 6-7; Gill, 1945, pI. 7,
figs. 3-4).
Another characteristic feature of Nipponocalymene is a surface ornamentation on theoccipital ring, posterior cephalic border, thorax,
and pygidium which consists mainly of scatteredpits. In Calymene species in which the wholeof the dorsal exoskeleton is known such as
C. platys Green, 1832 described and illustrated
by Hall and Clarke (1888, p. 3, pI. 1, figs. 1-6,
8-9, pI. 25, figs. 1--2) and C. allportiana Salter,
1865 described and illustrated by Shirley (1936,
p. 58, pI. 1, figs. 12-14) from the Wenlockianof Britain the dorsal surface of thorax andpygidium, and also of the occipital ring in C.
platys, is smooth, but never pitted. Of speciesof the tentaculata group, C. weberi also shows
the pygidial surface to be smooth but to be
never pitted. In addition the surface ornamenta-

99

tion of the posterior-most face of the glabella
along the occipital furrow which consists ofconsiderably large, elongate oval, somewhat
blister-like tubercles is also exclusively characteristic.
The lack of interpleural furrows on thepygidium separates Nipponocalymene hamadai
from the representatives of the tentaculata
group, which show better defined interpleuralfurrows as most of the other species of Calymene
do (see Siverter, 1980, p. 784).
The author comes to conclusion that
Nipponocalymene gen. nov., which is one of thelast survivors in the family Calymenidae, wasderived from Calymene through species ofSchrank's (1970) tentaculata group, especiallythrough the Kazakhstan species.
Nipponocalymene hamadai Kaneko,
gen. et sp. nov.

PI. 14, Figs. 1a-4b; PI. 15, Figs. 1a-2c;
PI. 16, Figs. 1a-12; Text-figs. la-b.
Derivation of name:-Patronym in honor ofProfessor Dr. Takashi Hamada of the Universityof Tokyo.
Holotype:-Incomplete individual, KAC-oT0111 [PA 17144] (PI. 14, Figs. la-I), coil.
A. Kaneko, 1980.
Specific diagnosis:-As for the genus.
Description:-Cephalon more than two times
as wide as long; anterior outline nearly straightin front, evenly rounded laterally; posterior
outline nearly straight between fulcra, at which
it deflects gently backward and then curves
forward again distally. Glabella with bell-shaped
outline resulting from well-developed 1p lateralglabellar lobe, not so strongly inflated forcalymenids; in lateral view, its frontal slope
from preglabellar furrow nearly vertical, becoming progressively gentler posteriorly; 1p lateralglabellar furrow deeply incised, directed diagonally as far as not so markedly projecting intermediate lobe, which divides it into two branches;anterior branch weak, curving forward andinward; posterior branch strong, curving back-100

Atsushi KANEKO

1cm
Text-fig. 1a. Restoration of Nipponocalym ene hamadai Kaneko, gen.
et sp. nov . (Dorsal exoskeleton).
ward and inward, then turning to run transversely, extending so far adaxiaJly that thenarrowest (trans.) part of glabeJla at its adaxial
extremity is much less than one third of thewidest part slightly anterior to postero-lateralcorner of lp lateral glabeJlar lobe; 2p lateralglabeJlar furrow directed inward and slightly
backward ; 3p lateral glabeJlar furrow weakly796. A Middle Devonian Trilobite Faunaem' - -_ _ _ ---.J

Text-fig. lb. Restorat ionof Nippo noca iymene hamadai Kaneko, gen. et sp. nov.
(Part of ventral side of cephalic region).
incised, directed inward and slightly forward;
Ip lateral glabellar lobe about one third as wide
(trans.) as glabella, more or less depressed , withroundly quadrilateral outline, separated fromfrontomedian glabellar lobe by a moderate
depression; 2p lateral glabellar lobe papillate,elongate (trans.), jointed to fixigenal butress,
separated from fron tomedian glabellar lobe bya weak depression; 3p lateral glabellar lobe small,elongate (trans.). Anterior border rolled, convex;
in dorsal view shortest (sag.) medially, widening
rapidly in front of antero-lateral corner offrontal glabellar lobe, attaining maximum length(exsag.) opposite axial furrow, and then slightly
shortening before widening distally; in lateralview rising in a gentle slope upward and forwardfrom base of preglabellar furrow to roun ded
crest, at which it curves over to become inclined
downward and backward to rostral suture; inanterior view weakly arched dorsally or nearlystraight in front of glabella. Preglabellar furrow
short (sag. and exsag.), moderately deep, U- to
V-shaped. Occipital ring about one-fifth as long(sag.) as wide, slightly wider than glabella acrosslateral glabellar lobe Ip , longest (sag.) medially,
then becoming progressively shorter (exsag.)laterally and slightly curving distally. Occipital
furrow shallowest medially, deepe ning progressively laterally, curving backwards and narrowin g(exsag.) behind adaxial part of Ip lateral glabellarlobe, finall y turning slightly forward. Axial

101

furrow sigmoidal , steep-sided , more or less overhun g by adaxial side of fixigena, shallowest at
distal end of occipital ring, moderately deep andconsiderably narrow (trans.) beside Ip lateralglabellar lobe , bridged by fixigenal butress at
2p lateral glabellar lobe , moderately wide (trans.)
at 3p lateral glabellar lobe, deepening abruptly
into anterior pit which is situated just anterior
to 3p lateral glabellar lobe, then expanding andbecoming slightly shallower at junction of preglabellar and anterior border furrows. Anterior
pit represented ventrally by a boss, on inneranterior slope of which there are excavatio ns
for anterior wing process of hypos tome. Facial
suture gonatoparian; converging ge ntly from w
in genal angle to junction of posterior andlateral border furrows, converging less gently
and then curving to nearly transversely fromthere to E, curving gently outward aroundpalpebral lobe from E to v, converging gently
from v to marginal border furrow, diverging
gently for a short distance from there to (3 inmarginal border, curving rapidly inward from
(3 to Q. Fixigena convex, attainin g maximum
height in region of palpebral lobe; in lateral view
from there sloping down steeply anteriorly toanterior border furrow and gently posteriorly
to posterior border furrow; in anterior view
sloping down evenly laterally in a moderate
curve. Palpebral lobe almost fla t abaxially,
sloping down very gently adaxially to fixigenal
butress; its mid-line at level of anterior marginof 2p lateral glabellar lobe . Librigena subtriangular in outline, with narrow (exsag. andtrans .) eye socle; genal field narrow (trans .),descending to lateral border furrow in a steep
slope. Lateral border furrow shallow, broadly(trans .) round-bottomed. Lateral border wide
(trans.), well rolled; its posterior-most portion
flexed backward and inward to form rounded
angle. Posterior border short (exsag.), sloping
slightly upward from axial furrow to fulcrum,at which it curves downward postero-laterally
and progressively lengthens (exsag.) before
becoming nearly parallel-sided near genal angle.
Posterior border furrow shortest (exsag.) mostadaxially, lengthening rapidly laterally to near

102

Atsushi KANEKO

fulcrum, from which it becomes parallel-sided
and then progressively slightly narrower before
ending near facial suture; its anterior slope
gentle; its posterior slope nearly vertical between
axial furrow and fulcrum, beyond which it becomes progressively gentler.
Rostral plate usual for calymenids; border
sector about one forth as long as wide, more orless longer (sag.) medially than laterally; con. nective suture gently convex outward, converging sharply postero-ventrally to join abaxial
extremity of inner arc of border sector; innerarc of border sector subparallel to rostral suture,marked by a sharp ridge; doublure sector only
poorly known.
Hypostome unusual for calymenids; anterior
margin gently convex forward; anterior border
flexed ventrally, but details unknown; anterior
wing unknown; median body pear-shaped inoutline, divided by no distinct median furrow;main part of median body homologous withanterior lobe of usual calymenid pattern, withstrongly convex (sag. and trans_) anterior
raised portion, whose top is bifurcate due todevelopment of a pair of stout, spur-like protuberances which are symmetrically arranged
with regard to sagittal line and directed ventrolaterally and anteriorly; rest of median bodybehind macula homologous with posterior
lobe of usual calymenid pattern, crescentic inshape, considerably short (sag. and exsag.),
rapidly sloping away posteriorly; macula prominent, ovr.te, somewhat pointed, situated at
postero-Iateral corner of median body and much
more posteriorly than posterior wing; lateralborder furrow most distinct opposite (trans.)
protuberances of anterior raised portion of
main part of median body, somewhat convergent
and narrowing (trans.) posteriorly; posteriorborder almost flat, projecting into two broad(trans.) but short (exsag.) spines; posteriorborder furrow represented by abrupt change ofslope, sometimes broken off medially.
Thorax of thirteen segments; Axial ringhighly arched, flexed forward and expandedslightly abaxially; articulating furrow moderately deep, round-bottomed, with steep anterior

slope and slightly gentler posterior slope, more
sharply incised laterally than medially; articulating half ring only slightly higher than bottomof articulating furrow, with clearly definedposterior margin. Inner part of pleurae tending
to be inclined slightly posteriorly in dorsal
view and to slope slightly upward abaxially intransverse section; outer part of pleurae sloping
down nearly vertically from fulcrum; posterior
band of pleura well rounded in exsagittal section,flexed slightly forward ad axi ally , continued
laterally to form bounding ridge around marginof articulating facet; anterior band of pleura
lower and shorter (exsag.) than posterior band,rounded in exsagittal section; pleural furrow
moderately deep, round-bottomed, diminishingadaxially.
Pygidium subrhombic in outline. Axis gently
arched, comprising an articulating half-ring,eight distinct and two indistinct axial rings
and a terminal piece; ring furrows tending toshallow medially; first ring furrow deepest andlongest (sag. and exsag.); subsequent ring furrows
becoming progressively shallower and shorter(sag. and exsag.), thus ninth and tenth furrows
failing to reach axial furrow and tenth furrow
lacking also its medial part near sagittal line;
terminal piece almost reaching pygidial extremity
which is deflected upward medially. Axial furrow
not so deep, broken off by junction first threering and pleural furrows. Pleural region defined
articulating half-rib (anterior pleural band of
first segment) and five ribs by five pleural furrows; first pleural furrow deepest, nearly straight,
cutting into broad (exsag. and trans.) pleuralfacet; subsequent furrows becoming progressively
slightly shallower posteriorly, extending onto
border roll, then shallowing rapidly and flexed
anteriorly to carry across its ventral surface todoublure; fifth pleural furrow never modified toform postaxial sector. Pleural ribs highly vaulted
in lateral view, tending to be flat-topped, withno interpleural furrows. Border roll strongly
rounded; its ventral portion relatively narrow(trans. and sag.), widest in front. Doublure
narrow, rolled in.
Surface ornamentation:-Moderately spaced,796. A Middle Devonian Trilobite Fauna
small to medium sized tubercles on frontomedianglabellar lobe except its posterior-most facealong occipital furrow, with which posterior
portion of 1p lateral glabellar lobe shares extremely large, elongate-oval, somewhat blisterlike tubercles; closely spaced, small to moderately large sized tubercles on anterior portion of
1p lateral glabellar lobe and outer slope of genal
area inside anterior and lateral border furrows;
fine granules scattered between these tubercles;
occasional small to medium sized tubercles andmoderately scattered granules on outer part of
inner raised portion of genal area inside borderfurrows except palpebral lobe, but decreasing
in number toward postero-adaxial corner of
inner raised portion opposite 1p lateral glabellar
lobe (tans.), which is apparently smooth; finegranules of various sizes moderately scatteredon inner part of border roll, but progressively
more closely spaced outward, densest on outerpart below the level of rostral suture including
border sector of rostral plate; 2p and 3p lateralglabellar lobe and palpebral lobe very weakly
granulated; doublure of librigena, doublure
sector of rostral plate and hypostome apparently
smooth; occipital ring, crest of posterior cephalicborder, thoracic and pygidial segments except
near axial furrow finely pitted scatteredly; granules on ventral portion of pygidial border rollsimilar to that on the ventral portion of cephalicborder roll below level of rostral suture; weak,fine granules discernible near lateral pygidial
margin; pygidial doublure apparently smooth;at least some of tubercles on dorsal surface offrontomedian glabellar lobe perforated_ Raised
surface of internal mould of cephalon covered
allover with closely spaced, fine pits of various
sizes each of which has a central swelling surrounded by raised rim, which are impressions ofcanal openings.
Observation:-In the holotype specimen (PI.
14, Figs. la-I) the anterior border is cracked bylongitudinal compression so that it looks as if it
had a sharp crest in lateral view (PI. 14, Fig. 1b).
While the paratype A (PI. 15, Figs. 1a-q) specimen is much larger than the holotype specimen,
the anterior border in the former is much lower

103

than that in the latter. This difference is intraspecific and partly attributable to growth change(see Holloway, 1980, p. 56). In a fragment of alarge cranidium (PI. 16, Fig. 2) the preglabellar
furrow is longer (exsag.) than those in the holotype and para type A specimens. Howeveranother large, damaged cranidium (PI. 16, Fig.
4) of similar size, though preserved as an internalmould, shows not so long (exsag.) preglabellar
furrow. The hypos tome in the holotype (PI. 14,
Figs. If-I) differs from that of the paratype B(PI. 14, Figs. 3a-d, PI. 16, Figs. 1b-c) in theconvexity of the median body, especially its
anterior raised portion, in the relative sizes
and shapes of the protuberances and in the
degrees of the angle between the protuberances.
In the holotype the anterior raised portion of themedian body is more developed so that the
protuberances are more elongate (exsag.) andless gently divergent ventrally. Nevertheless theauthor considers that the associated calymenid
remains from the present horizon are undoubtedly conspecific with each other and that thesedifferences may be intraspecific and in part
ontogenetic. The precise nature of the ornamentation on the thorax and pygidium except
pitting is not clear because of a layer of granularsilica over the external mould which is difficult
to remove, but their surface may be weakly
granulated. The surface of the internal mouldof the hypostome of the paratype C (PI. 14,
Figs. 2a-b) is covered with a layer of granularsilica, which never represents a surface ornamentation. The radiographs (PI. 16, Figs. 1b-c) showthat the bifurcated raised area of the hypostome
is never attributable to an artefact of preparation. Judging by the size of the fragment of thelargest pygidium (PI. 16, Fig. 9), the animal
may have attained about 20 cm in length.
Discussion:-With the Upper Silurian form
Calymene aff. weberi Maximova, 1968 andLower Devonian form C. kokbaitalensis Maximova, 1968, Nipponocalymene hamadai sharesvery similarly shaped glabellae and 1p lateralglabellar lobes, but differs from the Kazakhstan
forms in the nature of the preglabellar area. C.
aff. weberi has a more or less longer (sag. andAtsushi KANEKO

104

exsag.) pre glabell ar furrow meeting slightly
shorter (sag. and exsag.) anterior border atangular break in slope. C. kokbaitalensis has aselongate (sag. and exsag.) preglabellar area as
has been not only compared with C. macrocephala Prouty, 1923 (pl. 34, figs. 10-13, 18)from the Silurian of North America by Maximova(1968, p. 53) but also suggested to be a possible
representaive of Diacalymene by Whittington(1971, p. 458). Maximova (1978, p. 103, pl. 3,
figs. 11-12, text-fig. 1j2a-6) proposed a newsubgenus Calymene (Limbocalymene) on thebasis of that form. An Upper Silurian to Lower
Devonian form C. weberi Maximova, 1968 from
Kazakhstan was considered to be conspecificwith C. aff. weberi by Schrank (1970, p. 116,140) probably because of an impressional similarity in morphology of the preglabellar area,
but differs from the latter in a less developed
1p lateral glabellar lobe according to Maximova(1968, p. 51). Of these Kazakhstan forms, thus,
C. aff. weberi seems to be most closely related
to Nipponocalymene hamadai.

The Japanese species is slightly less similar
to the Upper Silurian form C. tentaculata(Schlotheim, 1820) from Germany, the typical
species of Schrank's (1970) species group 3 than
to the Kazakhstan froms except C. weberi inglabellar morphology. The German species has
a relatively well-developed 2p and slightly lessdepressed 1p lateral glabellar lobes. The preglabellar area of the Schrank's (1970, p. 139)
intraspecific variation type 3 in C. tentaculata,although a juvenile specimen, shows a rounded
anterior border and relatively shorter (sag. andexsag.) preglabellar furrow, but the anteriorborder is relatively longer (sag. and exsag.).
According to R. and E. Richter (1956, pp. 1819) C. beyeri R. & E. Richter, 1956 conspecificwith C. tentaculata has eight pygidial axial ringsand one or two additional ones as Nipponocalymene hamadai does. The Middle to Upper
Silurian form C. antigonishensis McLearn, 1924
from Nova Scotia, Canada may possibly fallwithin a range of variation of the morphologyof C. tentaculata as was pointed out by Schrank

Explanation of Plate 14
Figs.1a-4b. Nipponocalymene hamadai Kaneko, gen. et sp. nov.
Figs. la-I. Holotype, KAC-DT-0111 [PA 17144). Incomplete individual with somewhat displaced rostral plate and hypostome. a-k, rubber casts from external moulds; a-b, dorsal
stereo pair, X 1. c, left lateral view, X 1. d, anterior view, X 1. e, enlargement of part ofcranidium to show very large, elongate oval, somewhat blister-like tubercles on posteriormost face of glabella and pitting on occipital ring, dorsal view, X 2. f-g, ventral stereo pairof cephalic region, X 1. h-i, ventral stereo pair of hypostome, X 2. j, left lateral view ofhypostome, X 2. k, posterior view of ventral side of cephalic region, X 2. I, ventral view ofdamaged internal mould of hypostome, X 2.
Figs. 2a-b. Internal moulds of incomplete hypostome lacking protuberances of paratype C,
Sasaki-Koizumi coIl. [PA 17145) shown in Figures 5a-b of Plate 16, ventral stereo pair,

X 2.
Figs. 3a-d. Rubber casts from external moulds of hypostome of paratype B, KAC-DT-0113 [P A
17146) shown in Figures 1a-c of Plate 16. a-b, ventral stereo pair, X 2. c, left lateralview, X 2. d, posterior view, X 2.
Figs. 4a-b. Rubber casts from external moulds of damaged hypostome of paratype D, SasakiKoizumi coIl. [PA 17147) shown in Figures 6a-b of Plate 16. a, posterior view, X 2.
b, ventral view, X 2.
Fig. 5. Calymene antigonishensis McLearn, 1924.
Figs. 5a-c. Rubber casts from external moulds of hypostome of paratype, G.S.C. No. 5590, forcomparison with those of Nipponocalymene hamadai, gen. et sp. nov.; a-b, ventral stereo
pair, X 2. c, right lateral view, X 2.

KANEKO: A Middle Devonian Trilobite Fauna

Plate 14

796. A Middle Devonian Trilobite Fauna(1970, pp. 139-141).
In so far as the morphological information
known from the internal mould is concerned,
the Lower Devonian form C. killarensis Gill,
1945 from Australia is similar to Nipponocalymene hamadai in the nature of cranidium,
especially in the lateral profile (see Gill, 1945,
fig. 1B) and in the nature of the preglabellararea, but differs from the Japanese species inhaving more or less distinct 4p lateral glabellarlobe.
The Silurian form C. conspicua Schmidt,
1894 from Estonia was considered to be a possible synonym of C. ohhesaarensis Schmidt,
1984 by Schrank (1970, p. 116, 140).
Schmidt's 1894 paper in which the originaldescriptions of these Estonian species are presented is not available to the author, but his
paper (1907) in which the former is re-illustrated
is available. C. conspicua appears to have incommon a most similar preglabellar area with
Nipponocalymene hamadai, but differs from theJapanese form in having distinct 4p lateralglabellar lobe, in having laterally well expanded
antero-Iateral comer of the glabella, in having
somewhat slender glabella and in having wider(trans.) fixigena.
The above-mentioned comparisons demonstrate the closest relationship between the
Kazakhstan and Japanese species. Thus, also
another calymenid remains distributed from
Kazakhstan to Primorie become a subject of
discussion. However available information is too
unsatisfactory for detailed comparisons to bemade as shown below.
An incomplete cranidium illustrated as
Calymene sp. indet. by Weber (1932, pI. 1, fig.
2) from the Middle Devonian strata of the
Khodjent district in Turkestan is too strongly
damaged by weathering for us to say whether
or not it is a paillate-butressed form, but it ispossible to say that its frontal glabellar lobe
appears to be somewhat wider (trans.) than thoseof Calymene species of the tentaculata groupand the Japanese species.
Incomplete specimens described and illustrated as Calymene ex. gr. blumenbachii by

105

Maximova (1960, pI. 7, figs. 1-3) from thelower Middle Devonian (Di) of the Rudny Altai
also do not allow us to grasp characters usefulfor generic and subfamilial discrimination precisely. However, Maximova's figure 1 of plate 7
may possibly indicate the fixigenal butress
opposite (trans.) the 2p lateral glabellar lobe.
If this is a papillate-butressed form, its glabellar
shape shown in figure 1 may suggest somerelationship to those of Calymene species of thetentaculata group, but figure 2 shows, if notdeformed, a more slender glabella as in the
cranidium shown in figure 14 of Balashova's(1960) plate 1 of C. taimyrica Balashova, 1960
from the Llandovery of the Taimyr Peninsula.
Of the specimens described and illustrated
as Calymene spp. 0: and {3 by Maximova (1962,
pI. 10, figs. 4--6) from the Llandoverian to
Wenlockian strata of the Siberian platform,
two cranidia called Calymene sp. 0: seems to fallwithin the concept of the genus Calymene andto show relatively broad furrows surrounding
the glabella as species of the tentaculata groupdo, but they differ from the latter and theJapanese species in having much more rounded
lateral glabellar lobes. The pygidium called
Calymene sp. {3 shows a modified postaxial
sector of usual calymenid pattern.
In the Amur region, Modzalevskaya (1967,
p. 546) recorded only the generic nameCalymene without any further descriptions andfigures from the lower part of the Eifelian
Jmatchinskaya Suite. According to her the"Calymene" -bearing fauna in this region ischaracterized by the pronounced Appalachianaffinities as in Kazakhstan.
In West Primorie, Calymene ex. gr. blumenbachU and Calymene sp. were reported from theGrodekov district by Maximova and Organova(1959). The former represented by a fairly compessed, partial pygidium (fig. 1a) was comparedwith C. macrocephala, n. sp. from the Lower
Devonian (Dl) of northeastern Pribalkhas in
Kazakhstan, which was figured there for comparison (fig. 1 6 = fig. 3 of Maximova's (1968)
plate 8 of C. kokbaitalensis Maximova, 1968?,
non C. macrocephala Prouty, 1923). On theAtsushi KANEKO

106

other hand, the latter, represented by a largely
damaged cephalo-thorax (fig. B), was discussed
as allied to C. platys Green, 1832 described andillustrated by Hall and Clarke (1888) from theLower to Middle Devonian of New York State,
U.S.A. However the illustrations of thesecalymenid remains are too poor for us to assign
them precisely generically. It is safe to say thatat least the pygidium (fig. la) may possibly bea Kazakhstan affinity and have some relationshipto that of the Japanese species judging by thepossession of considerably reduced postaxial
sector.
Acknowledgments
The author is extremely grateful to Dr.
Allen R. Ormiston of Amoco Production Company, Tulsa, ()klahoma, for linguistic improvement of the present manuscript, invaluablesuggestions, useful literature and very kind encouragement; to Dr. Derek J. Siveter of the University of Hull, for instructive advices anddiscussions on many aspects of the present
calymenid material. The author is deeply indebted to Professor Dr. Takashi Hamada of the

University of Tokyo for reading over the manuscript, very kind instruction and encouragement;
to former Curator Dr. Eiji Matsumoto of National Science Museum, Tokyo, for helpful criticism
on earlier drafts of the manuscript and constantencouragement; to Professor Dr. Harry B.
Whittington of the University of Cambridge, for
his critical comment on the present calymenidmaterial. He expresses his sincere gratitude to
M.D. Yoshiaki Okamura of the Sekishin-kan
Museum, Kusatsu City, for his kind care inpreparing the radiographs used in the plate; toDr. M. J. Copeland of Geological Survey ofCanada, Ottawa, for supplying rubber casts
from the GSC collection and copies of usefulliterature; to Dr. I. A. Dubrovo of Palaeontological Institute, Moscow, for her kind care infilming many useful Russian literature; to Mr.
Ko-ichi Nakamura of Geological Survey of Japanand Mis Eleanor A. Gossen of New York State
Museum and Science Service, Albany, for supplying copies of many useful literature. Deep
appreciation is also expressed to Mr. Hitoshi
Koizumi of Kesen Chishitsu Kenkyl1sho (K.K.),
for many helpful informations and useful literature; to Mr. Teruo Ono and Mr. Kazuhiro

Explanation of Plate 15
Figs.1a-2c. Nipponocalymene hamadai Kaneko, gen. et sp. nov.
Figs. 1a-q. Paratype A, KAC-DT-D1l2 [PA 17148]. Incomplete individual. a-d, rubber casts
from external moulds of cephal on and thorax; a-b, dorsal stereo pair of cephalon anddisarticulated ten incomplete thoracic .segments (b), X 1. c, right lateral view of cephalon,
X 1. d, oblique antero-Iateral view of cephalon to show displaced incomplete librigena,
X 1. e, internal mould of cephalon and thorax, dorsal view, X 1. f-g, rubber casts frominternal moulds of cephalon shown in e, ventral stereo pair, XLi, enlargement of internalmould of median portion of glabella shown in e, details showing impressions of canal openings, X 7 (an interval of 0.1 mm between scale lines). k, enlargement of external mould of
most posterior thoracic segment shown in h, details showing scattered spines which are
impressions of pits, X 8. h, I, q, rubber casts from external moulds of pygidium and thorax;h, dorsal view of pygidium and disarticulated seven incomplete thoracic axial rings, X 1.
I, posterior view of pygidium, X 1. q, enlargement of dorsal surface of part of pygidium toshow pitting, dorso-posterior view, X 1.55. i, m-p, internal mould of pygidium and thorax;i, dorso-posterior view of pygidium and thorax, X 1. m, n, posterior stereo pair of pygidium,X 1. 0, left lateral view of pygidium and thorax, X 1. p, postero-ventral view of pygidium,
Xl.
Figs.2a-c. Rubber casts from external moulds of librigena, KAC-DT-0114 [PA 17149]. a-b,
dorsal stereo pair, X 1. c, oblique antero-Iateral view, X 1.

K ANEKO: A Middle D evonian Trilob ite Fauna

Plate 15

796. A Middle Deuonian Trilobite Fauna

Sasaki, for their kind cooperation and lendingof the specimens used in the plates; to Mr. Kazuo
Kitagawa, for his kind cooperation. Finally,
special thanks are due to Mr. Ken Kawanami,
the landowner of the present locality, for giving
his consent to the author's fossil hunting, Mis
Toshiko Imai and Mis Tamiko Nasu of thelibrary of Department of Geology and Mineralogy, Faculty of Science, Kyoto University,
for providing facilities to search the literature.
Repository of material.·-University Museum,
University of Tokyo ([PA]). Kaneko Collection (KAC-oT); 15-7 Fukae-honmachi 1-chome,
Higashinada-ku, Kobe, 658, Japan.
References
Angelin, N. P. (1854): Palaeontologia Scandinavica. I: Crustacea formationis transitionis. Lund Fasc. 2, p. 21-92, pis. 25-41,
Stockholm.
Balashova, E. A. (1960): Trilobites of the Middle
and Upper Ordovician and Lower Silurian
of Eastern Taimyr. Leningrad National
Univ. p. 1-111, pis. 1-6, Leningrad (inRussian).
Barrande, J. (1846): Notice preliminaire sur Ie
Systeme Silurien et les trilobites de Boheme.
Leipzig, i-vi, 97 p.
--(1852): Systeme Silurien du centre de la
Boheme. 1 ere partie: Recherches pa/eontologiques, vol. 1, Crustaces: Trilobites. ixxx, 935 p., 51 pis., Prague and Paris.
Brongniart, A. (1822): in Brongniart, A. andDesmarest, A. G., Historie naturelle descrustaces fossiles; les trilobites. 154 p.,
pis. F, G, Levrault, Paris.
Briinnich, M. T. (1781): Beskrivelse over Trilobiten. Nye Sammling. Danske Vidensk.
Selsk. Skrift. (not seen).
Burmeister, H. (1843): Die Organisation der
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Campbell, K. S. W. (1967): Trilobites of theHenryhouse Formation (Silurian) in Oklahoma. Bull. Oklahoma Geol. Surv. 115, p.
1-68, pis. 1-19.
Chatterton, B. D. W. (1971): Taxonomy andontogeny of Siluro-Devonian trilobites fromnear Yass, New South Wales. Palaeontographica Abt. A, Bd. 137, p. 1-108, pis.

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1-24.
--and Campbell, K. S. W. (1980): Silurian
trilobites from near Canberra and somerelated forms from the Yass Basin. Ibid., Bci.
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Copper, P., Tazawa, J., Mori, K. and Kato, M.
(1982): Atrypa (Devonian Brachiopoda)
from Japan. Trans. Proc. Palaeont. Soc.
Japan, N.S., no. 127 (749), p. 368-374,
pI. 59.
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Calymenidae from the Palaeozoic Rocks ofVictoria. Proc. Roy. Soc. Victoria, vol.
56 (N.S.), pt II, p. 171-185, pI. 7.
Green, J. (1832): A monograph of the Trilobitesof North America; with colored models of
the species. 94 p. (Philadelphia).
Hall, J. and Clarke, J. M. (1888): Descriptionsof the trilobites and other Crustacea of the
Oriskany, Upper Helderberg, Hamilton,
Portage, Chemung and Catskill Groups.
New York Geological Survery, Palaeontology of New York, vol. 7, p. 1-236.
Hass, W. (1968): Trilobiten aus dem Silur und
Devon von Bithynien (NW-Tiirkei). Palaeontographica Abt. A, Bd. 130, p. 60-207,
pis. 1-12.
Holloway, D. J. (1980): Middle Silurian trilobitesfrom Arkansas and Oklahoma, U.S.A.
Palaeontographica Abt. A, Bd. 170, p. 1-85,
pis. 1-20.
Ingham, J. K. (1977): A monograph of theupper Ordovician trilobites from the Cautley
and Dent districts of Westmorland andYorkshire. Palaeontogr. Soc. (Monogr.), vol.
130 (for 1976) (546), part 3, p. 89-121,
pis. 19-27.
King, W. B. R. (1923): The Upper Ordovician
rocks of the south-western Berwyn Hills.
Quart. Jour. Geol. Soc. London, vol. 79, p.
487-507, pI. 26.
Kobayashi, T. and Hamada, T. (1977): Devonian
trilobites of Japan in comparison with Asian,Pacific and other faunas. Palaeont. Soc.
Japan, Spec. Pap., no. 20, 202 p., 13 pis.
Kummerow, E. (1928): Beitrage zur Kenntnis
der Fauna und der Herkunft der Diluvialgeschiebe. Jahrb. PreuB. geol. Landesanst,
Bd. 48, p. 1-59, pis. 1-2.
Lindstrom, G. (1901): Researches on the visualorgans of the trilobites. Vetensk. Acad.
Handl., 34 (8), p. 1-86, pis. 1-6.

Atsushi KANEKO

108

Maximova, Z. A. (1960): Palaeontological basisof the Palaeozoic stratigraphy of the Rudny
Altai 7: Devonian and Carboniferous trilobites of the Rudny Altai. Trudy VSEGEI,
vol. 7, p. 1-123, pis. 1--9 (in Russian).
--(1962): Trilobites from the Ordovician andSilurian of the Siberian platform. Trudy
VSEGEI, N.S., vol. 76, p. 1-176, pis. 1-13
(in Russian).
--(1967): Late Silurian and early Devonian
trilobites of Central Kazakhstan. Inter-vol. 165, p. 1-208, pis. 1-35 (in Russian).
- - (1978): Some new Devonian trilobites.

national Symposium on the Devonian
System, Calgary, vol. 2, p. 777-787, pis.

British Palaeozoic rocks, with a detailed
systematic description of the British Palaeozoic fossils in the Geological Museum of
the University of Cambridge. Fasc. 1, iii-

1-4.
- - (1968): Middle Palaeozoic trilobites ofCentral Kazakhstan. Trudy VSEGEI, N.S.,

Annals of the All-Union Palaeont. Soc.,
vol. 21, p. 94-107, pI. 3 (in Russian).
--and Organova, N. M. (1959): The first
discovery of remains of a Devonian faunain West Primorie. Doklady Acad. Nauk
SSR, vol. 128, no. 3, p. 594-595 (in Russian).
McCoy, F. (1851): in, Sedgwick, A. and McCoy,
F. A., A synopsis of the classification of theiv, p. 1-184, pis.

1A-L, London andExplanation of Plate 16
Figs.1a-12. Nipponocalymene hamadai Kaneko, gen. et sp. nov.
Figs. 1a-c. Paratype B, KAC-DT-Oll1 [P A 17150]. Incomplete individual preserved as internal mould except hypostome, of which rubber casts from external moulds are shown in
Figures 3a-d of Plate 14. a, dorsal view, X 1. b, right lateral, X-ray view showing hypostome
approximately in position, about X 1.55. c, posterior, X-ray view showing bifurcated raisedarea of hypostome in matrix, about X 1.4.
Fig. 2. Rubber cast from external mould of fragment of large cranidium, KAC-DT-0115 [PA
17151], showing relatively long (exsag.) preglabellar furrow, dorsal view, X 1.
Fig. 3. Rubber cast from external mould of incomplete cranidium, KAC-DT-0116 [PA 17152],
dorsal view, X 1.
Fig. 4. Internal mould of incomplete deformed cranidium, KAC-DT-0123 [PA 17153],
collected by T. Ono, dorsal view, X 1.
Figs. 5a-b. Paratype C, Sasaki-Koizumi coil. [PA 17154]. Incomplete individual with hypostome shown in Figures 2a-b of Plate 14. a, dorsal view of internal mould, X 0.7. b,
dorsal view of rubber cast from external mould to show pitting.
Figs. 6a-b. Paratype D, Sasaki-Koizumi coil. [PAl 7670]. Incomplete individual. a, dorsal viewof internal mould with displaced hypostome of external mould, from which rubber castshown in Figures 4a-b of Plate 14 is taken, X 0.7. b, dorsal view of cast from externalmould, X 1.
Fig. 7. Incomplete individual, KAC-DT-0117 [P A 17671], dorsal view of internal mould,
X 0.7.
Figs.8a-b. Paratype, KAC-DT-0118 [PA 17672]. Incomplete pygidium. a, dorso-posteriorview of internal mould, X 1. b, dorso-posterior view of rubber cast from external mould,

Xl.
Fig. 9. Rubber cast from external mould of fragment of largest pygidium, KAC-DT-0119 [PA17673], dorso-posterior view, X 1.
Fig. 10. Rubber cast from external mould of incomplete pygidium, KAC-DT-0120 [PA 17674],
dorso-posterior view, X 1.
Fig. 11. Paratype, KAC-DT-0121 [PA 17675]. Rubber cast form external mould of incomplete,somewhat depressed pygidium, dorso-posterior view, X 1.
Fig. 12. Internal mould of incomplete pygidium, KAC-DT-0122 [PA 17676], dorso-posteriorview, X 1.

KANEKO: A Middle Devonian Trilob ite Fauna

Plate 16

796.

A Middle Devonian Trilobite Fauna

Cambridge.
McLearn, F. H. (1924): Palaeontology of the
Silurian Rocks of Arisaig, Nova Scotia.
Canada Dept. Mines, Geol. Surv., Mem.
137, no. 118, geol. ser., p. 1-180, pis. 130.
McNamara, K. J. (1979): Trilobites from theConiston Limestone Group (Ashgill Series)of the Lake District, England.
Palaeoontology, vol. 22, pt. 1, p. 53-91,pls. 7-12.
Modzalevskaya, E. A. (1967): Biostratigraphic
subdivision of the Devonian in the Far East
and Transbaikal region, USSR. International
Symposium on the Devonian System,
Calgary, vol. 2, p. 543-549.
Pillet, J. (1968): Les Calymene devoniens
d'Europe et d'Afrique du Nord. Ann. dePaleont. Invert., vol. 54, p. 67-89, pIs.
A-H.
Price, D. (1982).: Calymene quadrata King,
1923 and allied species of trilobites fromthe Ashgill of North Wales. Geol. Mag.,
vol. 119, no. 1, p. 57-66, pIs. 1-3.
Prouty, W. F. (1923): in, Swartz, C. K. and
Prouty, W. F., Trilobita, in Systematicpalaeontology of Silurian deposits. Mary·land Geol. Surv., Silurian, p. 1-794, pis.
1-67.
Richter, R. and Richter, E. (1954): Die Trilobiten des Ebbe-Sattels und zu vergleichende
Arten (Ordovizium, Gotlandium/Devon).
Abh. Senckenb. Naturf. Ges., 488, p. 1-76,
pis. 1-6.
Salter, J. W. (1865): The Trilobites of the
Silurian, Devonian &c., Formations. Palaeontogr. Soc. (Monogr.), vol. 17 (for 1863)(72), part 2, p. 81-128, pis. 7-14.
Schmidt, Fr. (1894): Revision der ostbaltischen
silurischen Trilobiten, Abt. 4. Mem. Acad.
imp. Sci., Ser. 7, 42, p. 1-93, pIs. 1-6(not seen).
- - (1907): Revision der ostbaltischen silurischen
Trilobiten, Abt. 6. Ibid., Ser. 8, 20, p. 1104, pIs. 1-3.
Schrank, E. (1970): Calymeniden (Trilobita)
aus silurischen Geschieben. Ber. deutsch.
Ges. geol. Wiss. A, Geol-Paliiont. Bd. 15(1), p. 109-146, pIs. 1-12.
Shirley, J. (1933): A redescription of the known
British Silurian species of Calymene (s.l.).
Mem. Proc. Manchester lit. phil. Soc., vol. 77,

109

p. 51-67, pI. l.
- - (1936): Some British trilobites of the
Family Calymenidae. Quart. Jour. Geol.
Soc. London, vol. 92, p. 384-422, pIs.
29-3l.
Siveter, D. J. (1977): The Middle Ordovicianof the Oslo region, Norway, 27. Trilobitesof the family Calymenidae. Norsk. geol.
tiddskr., vol. 56 (for 1976), p. 335-396,
pis. 1-13.
--(1979): Metacalymene Kegel, 1927, acalymenid trilobite from the Kopanina
Formation (Silurian) of Bohemia. Jour.
Paleont., vol. 53, no. 2, p. 367-379, pIs.
1-3.
- - (1980): Evolution of the Silurian trilobite
Tapinocalymene from the Wenlock of the
Welsh Borderlands. Palaeontology, vol. 23,
pt. 4, p. 783-802, pis. 97-10l.
- - (1983): Caly mene lawsoni and allied species
from the Silurian of Britain and their stratigraphic significance. In, Briggs, D. E. G.
and Lane, P. D., Trilobites and other earlyarthropods: papers in honour of Professor
H. B. Whittington, F. R. S. Spec. Pap. in
Palaeontology, no. 30, p. 69-88, pis. 7-10.
Temple, J. T. (1975): Early Llandovery trilobites from Wales with notes on British
Llandovery calymenids. Palaeontology, vol.
18, pt. 1, p. 137-159, pis. 25-27.
Tillman, C. G. (1960): Spathacalymene, an unusual new Silurian trilobite genus. Jour.
Paleont., vol. 34, no. 5, p. 891-895, pI. 116.
Weber, V. N. (1932): Trilobites of the Turkestan.
Trudy VGRO, NKTP, SSR, p. 1-157, pIs.
1-4 (in Russian with English summary).
Whittington, H. B. (1941): Silicified Trenton
trilobites. Jour. Paleont., vol. 15, no. 5, p.
492-522, pIs. 72-75.
- - (1956): Silicified Middle Ordovician trilobites: the Odontopleuridae. Bull. Mus.
Compo Zool. Harv., vol. 114, no. 5, p. 155288, pis. 1-24.
- - (1959): Family Calymenidae Burmeister,
1843. in, Moore, R. C. (ed.): Treatise on
invertebrate palaeontology, Pt. 0, Arthropoda 1, Geol. Soc. Amer. and Univ. Kansas
press, 560 p., 415 figs.
--(1971a): A new calymenid trilobite from
the Maquoketa Shale, Iowa. In, Dutro, J.
T. Jr. (ed.), Paleozoic Perspectives: A

Atsushi KANEKO

110

paleontological tribute to G. Arthur Copper.

Smithsonian Contrib. Paleobiol., no. 3, p.
129-136, pis. 1-2.

Kitakami Mountains ~tJ:.Il1:1(g,--(1971b): Silurian calymenid trilobites fromthe United States, Norway and Sweden.
Palaeontology, vol. 14, pt. 3, p. 455-477,
pis. 83-89.

Nakazato '*'ll1.

~tJ:.Il1:l1!!.,*,{fllT;f- /*,*,ll1.~it(7)C:::~.!Rtb:itJllfl;::',""?~,-c-~(7) 2,*
0*
1 '""?mhh 7.:> t-.:ft-C;i; 7.:>
Calymenidae f4:Si.::.tn--cIt.,*,{fllT;f-/*,*,ll1.~ N3 ll1l~it(7) Calymenidae f4i.::.~-t7.:> Imf'lfi~~ttL, ;:.;h
i.::.:tt LmJ!lt~mpl§ L Nipponocalymene c ~i'r Lt.:o mji(7)WEJ3It.-.tt. Calymelle J!lt(7)mSi:

lll't~~ :b :1t:fE -t 7.:> ;'J;, Jili:ffZ""(';i; 7.:> rl§ r.::.tn--c :<I>:f4 c L -c lil'!YJ-c *,H·fd.cJf:31't~~-t )'l~-!;"
f4r.::.It-·-cr~,*,*l'illM~I.::.~~~!t t: 7.:>~1rI.::.:i, jjfi11nE,*,*~l:I'::'Pf£iJ;, ~~I.::.tn--cIt.iE,*,*~ ~~¥J;fIIll'::' 1 ~HX: L -c m:b.h 7.:>0 Mll1lii1i~:&O:M~(7)jfJ!i.~t.J' G, ~~'i Calymene ~(7)r*J, Schrank (1970) (7)n\.~!H.::..l:: 7.:> tentaculata !l" It.- -7"1'::', C I):bft;:'(7)!l"~-7"(7)~f9~~/it(7).~.:b.<~~~h~7.:>o~G<;:'h.~~*-t7.:>t(7)c~x.Gh7.:>o~TMETrans. Proc. Palaeont. Soc. Japan, N.S., No. 138, pp. 111-137, pIs. 17-19, July 15,1985

797. INTRASPECIFIC VARIATION IN THREE SPECIES OF GLOSSAULAX(GASTROPODA: NATICIDAE) FROM THE LATE CENOZOIC STRATA IN
CENTRAL AND SOUTHWEST JAP AN*
RYUICHI MAJIMA
Institute of Geoscience, University of Tsukuba, Ibaraki 305, Japan

Abstract.
The intraspecific variation within three Glossaulax species, G.
hyugensis (Shuto), G. nodai, n. sp. and G. hagenoshitensis (Shuto), which hadflourished in the late Cenozoic waters of Japan, was studied on the basis of morethan 600 individuals collected from 24 localities. The three species overlap stratigraphically and geographically, and are distinguished from other Glossaulax
species by having a nearly flat umbilical wall and a spiral angulation dividing thebase and the umbilical wall.
"Dimorphic" variation is recognized in the callus morphology of the adults ofG. hyugensis and G. hagenoshitensis. One adult variant of G. hyugensis is similar
to that of G. hagenoshitensis, and the other adult variant of the former species issimilar to that of the latter, whereas the frequency of the similar adult variants ofthe two species is extremely different. G. nodai, however, is uniform in callus
morphology throughout growth. In the callus morphology, the juvenile of G.
hyugensis and that of G. hagenoshitensis are similar to G. nodai, and to one formof the adult "dimorphic" variation of G. hyugensis, respectively. Furthermore,
G. hagenoshitensis is divisible into two allopatric forms in the sculpture of subsutural area and of umbilical wall margin. The mode of the ontogenetic variationsof the three species is explained by a heterochronic model in which an imaginary
ancestral species is presumed. G. hagenoshitensis has been taxonomically confusedwith Polinices sagamiensis Pilsbry and Glossaulax reiniana (Dunker), but is clearly
distinguished from these two species on the basis of umbilical morphology.

Introduction

yama (1935); Siphonalia by Makiyama (1941);
Paphia by Shuto (1957); Anadara by Noda
(1965); and Cryptopecten by Hayami (1973).
Despite the large numbers of naticid gastropods from these strata, they have been little
studied except for Shuto's (1964) descriptionof species from the late Miocene to early Pleistocene Miyazaki Group of southeast Kyushu.
Shuto (1964) proposed the new species
Polinices (Glossaulax) hyugensis and P. (G.)
hagenoshitensis, both of which have been generally considered to be endemic and rare in the

Late Cenozoic strata distributed along the
Pacific coast of southwest Japan yield abundantwarm-water molluscan species, collectively called
the Kakegawa Fauna (Otuka, 1939; Chinzei,1978). Japanese paleontologists have provided
taxonomical and evolutional studies for manytaxa from these strata: for example, Umbonium
by Makiyama (1925), Suzuki (1934) and Sugi*Received April 26, 1984; Read January 22,
1984, Annual Meeting at Kyoto University.

111

112

Ryuichi MAJIMA

Miyazaki Group. However, the two species,
especially in G. hagenoshitensis, occur abundantly in the Kakegawa Fauna. The apparent rarityof G. hagenoshitensis is partly because it has
been confused with Polinices sagamiensis Pilsbry
and Glossaulax reiniana (Dunker). Glossaulax
hyugensis, G. hagenoshitensis and their closely
related species G. nodai, n. sp. are characterized
by a nearly flat umbilical wall and a spiralangulation dividing the base and the umbilicalwall, by which they are easily distinguishedfrom P. sagamiensis and other Glossaulax species.
G. hyugensis and G. hagenoshitensis show
"dimorphic" variations at the adult stages andtheir juveniles differ, to varying degrees, fromthe adults. G. nodai, n. sp., however, has an
uniform shell morphology throughout growth.
Furthermore, G. hagenoshitensis is divisible into
two allopatric forms. The three species cantherefore be divided into ten phenotypes:
G. hyugensis has one juvenile and two adultphenotypes; G. hagenoshitensis two juvenile
and four adult phenotypes; and G. nodai one
phenotype. The aim of this study is to describe
the ten phenotypes of the three Glossaulax
species; to evaluate the intraspecific variationsof the three species as species characters; topropose a heterochronic model to explain how
the differences of the ontogenetic variation
among the three species occur phylogenetically;
to provide revised diagnoses for G. hyugensis andG. hagenoshitensis; and to propose the new
species G. nodai.
The term "phenotype" used in this stu dy issomewhat of a misnomer because the juvenile
forms of G. hyugensis and G. hagenoshitensis
are also designated as "phenotype." In the modelof heterochrony proposed herein, this term will
be used in the same sense as growth stage.
Morphological terminology in the present
paper conforms to that adopted by Marincovich(1977, text-fig. 10) except for "umbilical wall"
which shows the umbilical side of body whorl
excluding funicle and above it. In the three
Glossaulax species, umbilical wall is sharply
separated from the base by a spiral angulation.
The specimens studied here are preserved in

Institute of Geoscience, University of Tsukuba(IGUT), Geological Institute of Yokohama
National University (GIYU), and Departmentof Geology, Faculty of Science, Kyushu University (GK).
Localities
All specimens studied here were obtained
from late Cenozoic strata in central and southwest Japan (Text-fig. 1)_ The chronology ofthese strata is mainly based upon planktonic
foraminiferal biostratigraphy, and radiometricand magnetostratigraphic datings (Tsuchi ed.,1979; 1981). These strata range in age from late
Pliocene to early Pleistocene. The stratigraphic
positions of fossil localities and numbers ofspecimens examined from each locality aresummarized in Table 1. The formations andlocalities treated in this study are in the following geographic areas (Text-fig. 1):
Miyazaki area. -This area is situated in theeastern part of Miyazaki Prefecture. The five
localities (Locs. M-I-5) in this area areassigned to the late Pliocene to early Pleistocene
Takanabe Member of the Koyu Formation of
the Miyazaki Group (Shuto, 1961). The Takanabe Member is composed mainly of well bedded
siltstone, within which intercalated, thin (lessthan 1 m) sandstone beds have yielded thespecimens studied herein. Shuto (1961) recognized six fossil horizons in the Miyazaki Group:from the first to the sixth fossil horizons inascending order. Among them, the fourth tosixth fossil horizons occur in the Takanabe
Member; that is, the fourth fossil horizon at Locs.
M-l, M-2 and M-3, the fifth at Loc. M-4 and thesixth at Loc. M-5 (Table 1). The PliocenePleistocene boundary is drawn between thefifth and sixth fossil horizons (Shuto, 1983)_
M·l: Road cut at Hagenoshita, Takanabemachi, Koyu County (lat. 32°08.8 'N.; long.
l3l 0 31.l'E.); fine-grained sandstone. M-2: Road
cut at ° Oku, Shintomi-machi, Koyu County(lat. 32 47.7'N.; long.132°29.2'E.); fine-grainedsandstone. M-3: Road cut at Koonji, Takanabe·machi, Koyu County (lat. 32°06.7'N.; long.

797.

113

Variation of Glossaulax (Gastropoda)
N

Kakegawa
2 Km
I

a.

.K-8
KA

Miyazaki

N

1

2 Km

Nobori

1

2 Km
I

Tonohama

1
Text-fig.1.

Maps showing fossil localities. See Shikama and Masujima (1969) for the Loc.

N-1 in the Kamakura area.

Ryuichi MAJIMA

114
Table 1.

Stratigraphic and geographic distributions of the specimens of Glossaulax hyugensis(Shuto), G. nodai, n. sp. and G. hagenoshitensis (Shuto) examined in this study. The
numbers in parentheses show number of specimens. The specimens are reposited in
Institute of Geoscience, University of Tsukuba (IGUT), Geological Institute of Yokohama National University (GIYU), and Department of Geology, Faculty of Science,
Kyushu University (GK).

~~
Forrnation

Glossaulax
hyugensis lShuto)

Miyazaki Are a
JoI,iyazaki Group
Sixth fossil horizon

Glossaulax
nodai n. sp.

GIQ§sauiax
hagenoshitensis (Shuto)(Phenotypes 3Ja, 31 aand 3Ua)§l,Qssaulax~genoshi!.!.I!ili(Shuto)(Phenotypes 3Jb, ~,and 3Ub I

M-5: IGUI no. 15698( I)

Early Pleistocene-.-----

F i f th f os 5 i I horizon
late PI iocene

M-4 : GK. 179U7(1)t~ IGUI no. 15699(50)Fourth fossil horizon
Late Pliocene-----

IGUI no. 15700(46)M-I GIYU no. 568(8)GK. L8003(1)K-2: IGUI no. 15702(16)M-3: GIYU no. 571 (7)M-I: GIYU no. 570( I)
GK. L8009(1)M-2: IGUI no. 15701(30)K-3: GIYU no. 571(2)--/lobor i and Tonohama
Are asTonohallla Group

1_2:[IGUI no. 15694(25)
IGUI no. 15693(28)Ananai Formation

1-3: IGUT no. 15692( I)

Late PI iocene
Nobori Formation
Late Pliocene

I-I: IGUI no. 15691 (9)I -I: IGUI no. 15690(2)Kakegawa Area
Kakegawa Group

Upper Kakegawa

K- 3: IGUI no. 15717( 18)

Forllation
Hosoya Member

Early Pleistocene
Lower Kakegawa

Formation
lenna Hellberlate Pliocene

K-8: IGUI no. 15714( 15)K-9: IGUI no. 15715(2 )K-9 : IGUI no. 15716(3)K-I: IGUI no. 15703(152)
K-2 : IGUI no. 15704(17)K-IO: IGUI no. 15705( 121)
K-II: IGUI no. 15707l 21)

Dainichi Member
late Pliocene

K-13:[ IGUI no. 15695(1)IGUI no. 15696(2)K-I 7: IGUI no. 15697( 6)Kamakura Area
Nojilll3 ForlRation
Early Pleistocene
Kanaza .... a Area

Omma Formation
Early Pleistocene[GIYU no. 562(1)N-I: GIYU no. 563(1)GlYU no. 564( I)K-12 : IGUI no. 15712( I I)
K-13 :
K-14 :
K-15:
K-16 :
K-I 7:IGUI no.
IGUI no.
IGUI no.
IGU I no.
I GU I no.

15713 ( 3)15709( II)15710(6)15711 (17)15706(48)

N-I: GIYU no. 56 7( 8)

0-1 : IGUI no. 15688(10)0-2 : IGUI no. 15718( 2)0-3: IGUI no. 156B9( I)797.

Variation of Glossaulax (Gastropoda)

131°30.2'E.); sandstone. M·4: Road cut at
Nihonmatsu, Takanabe-machi, Koyu County(loc. MI·5551 of Shuto, 1961, lat. 32°06.7'N.;
long. 131°31.7'E.); fine-grained sandstone. M·5:
Construction excavation at Torihama fishingport, Kawaminami·machi, Koyu County (lat.
32°10.1 'N.; long.131 °33.1 'E.); fine-grained sandstone.

Nobon' and Tonohama areas. -The two areas
are located in the southeastern part of Kochi
Prefecture. The late Pliocene Tonohama Group,
which is divided into the Nobori, Nahari andAnanai Formations in ascending order (Katto
et al., 1953), is exposed in these areas. The
Nobori Formation (Loc. T·1) consists mainlyof massive siltstone, and the Ananai Formation(Locs. T·2 and T·3) is mainly massive sandstone
with sporadic pebbles.
T·1: Large quarry at Nobori, Hane-machi,
Muroto County (lat. 33°22.2'N.; long. 134°
03.5'E.); siltstone. T·2: Road cut, about 450 m
north from Tonohama Village, Yasuda·machi,
Aki County (Iat. 33°26.6'N.; long.133°58.2'E.);
fine-grained sandstone. T-3: Stream-side cliff
in small valley, about 350 m northwest from
Higashidani Village, Yasuda-machi, Aki County(lat. 33°26.7'N.; long. 133°58.4'E.); fine- tomedium-grained sandstone.

Kakegawa area. -This area is situated in thesouthwestern part of Shizuoka Prefecture.
The Kakegawa Group yields the fossils studied
at thirteen localities (Locs. K·1-3, 8-17). The
Kakegawa Group is divided into the Lower
Kakegawa, Upper Kakegawa and Soga Forma·tions in ascending order (Makiyama and Saka·
moto, 1957). The Lower Kakegawa Formation
is divided into two members: the Dainichi Sand
(Locs. K·1, 2, 10-17) below and the Tenno
Sand (Locs. K·8, 9) above. The basal part of
the Upper Kakegawa Formation is designatedthe Hosoya Tuffaceous Silt Member (Loc. K·3).
The Pliocene-Pleistocene boundary coincides
with a tuff bed (Hosoya Tuff) in the lowermost
part of the Hosoya Tuffaceous Silt Member(Tsuchi and Ibaraki in Tsuchi ed., 1979).
K·1: Stream-side cliff in small valley, about
700 m northwest from Dainichi Village, Fukuroi

115

City (lat. 34° 48.7'N.; long.137°56.4'E.); fine- tomedium-grained sandstone with pebbles. K-2:
Stream-side cliff in small valley, about 120 m
southeast from Loc. K-1 (lat. 34° 48.7'N.; long.
137° 56.4 'E.); fine- to mdium-grained sandstone
with pebbles. K-3: Road cut near Kakegawa
Baseball Field, about 650 m southeast from
Hosoya National Railway Station, Kakegawa
City (lat. 34°47.1 'N.; long. 137°58.2'E.); siltpebble bearing medium-grained sandstone intercalated in tuffaceous siltstone. K·8: Road cut at
Asuka, Kakegawa City (lat. 34°47.3 'N.; long.
137°59.9'E.); fine- to medium-grained sandstone. K·9: Road cut at Shimo-Saigo, Kakegawa
City (lat. 34 v 46.7'N.; long. 138°01.2'E.); silty
sandstone. K-10: Road-side cliff, about 500 m
east from Kami-lida Village, Mori-machi, Suchi
County (lat. 34 ° 48.4 'N.; long. 137° 55.7 'E.); fineto medium-grained sandstone with pebbles. K-11:
Road cut, about 500 m southeast from HongoHigashi Village, Kakegawa City (lat. 34°48.1 'N;
long. 137° 58.0 'E .); fine- to medium-grainedsandstone. K-12: Road cut at the east entranceof small tunnel, about 250 m southwest from
Honohashi Village, Kakegawa City (lat. 34 °47.3 'N.; long. 138 ° 00.6 'E .); conglomerate withmedium-grained sandstone matrix. K-13: Small
tunnel cut, about 300 m east from Tonoya
Village, Kakegawa City (lat. 34°47.7'N.; long.
137°58.3'E.); fine-grained sandstone. K·14:
Small river-side cliff, about 500 m north from
Dainichi Village, Fukuroi City (lat. 34 ° 48.6 'N.;
long. 137°56.5'E.); fine- to medium-grainedsandstone. K-15: Small river-side cliff, about 200
m south from Loc. K-14 (Iat. 34°48.4' N.;long.
137°56.5'E.); fine- to medium-grained sandstone.
K·16: Road cut, about 250 m east from Loc.
K-14 (lat. 34 ° 48.5 'N.; long. 137° 56.6' E.); fine- tomedium-grained sandstone. K·17: Road cut,
about 1000 m west from Haranoya National
Railway Station, boundary between Fukuroi and
Kakegawa Cities (lat. 34°48.4'N.; long. 137°
56.8 'E .); fine- to medium-grained sandstone.

Kamakura area. -This area is located in thebase of Miura Peninsula, Kanagawa Prefecture.
At only one locality (Loc. N.1) of this area,
fossils studied herein have been collected fromthe early Pleistocene Nojima Formation of the
Kazusa Group. The Nojima Formation is com·posed mainly of tuffaceous fine·grained sand·Ryuichi MAJIMA

116

stone or siltstone with many scoriaceous or
pumiceous patches (Shikama and Masujima,1969).
N -1: Large sand quarry, about 900 m northeast from Kitakamakura National Railway Station, Kamakura City (Ioc. 318-II of Shikama andMasujima, 1969): tuffaceous fine- to mediumgrained sandstone with pebbles.

Kanazawa area. -This area is situated in thecentral part of Ishikawa Prefecture. The three
localities (Locs. 0-1-3) in this area belong to
the early Pleistocene Omma Formation whichis composed mainly of medium-grained sandstone.
0-1: River bed of the Sai River, about 1000
m southeast from the Okuwa bridge, Okuwamachi, Kanazawa City (lat. 36°31.6'N.; long.
136° 41.2'E.); fine- to medium-grained sandstone.
0-2: River-side cliff of the Asano River, Tatemachi, Kanazawa City (lat. 36°31.3'N.; long.
136° 42.4 'E.); fine- to medium-grained sandstone. 0-3: Transported subangular boulder,on the river floor of the Asano River, about 150
m west from the streets of Fukuroitaya-machi,
Kanazawa City (lat. 36°30.8'N.; long. 136° 42.5'
E.); fine-grained sandstone.

Associated faunas
The Kakegawa, Omma-Manganji (=OmmaManganzi) and Kuroshio Faunas (Chinzei, 1978)
contain the three Glossaulax species.
The Kakegawa Fauna, warm-water molluscs
of late Miocene to early Pleistocene age, occurs
in strata along the Pacific coast of southwest
Japan, including the Miyazaki Group (Locs. M1--{», the Tonohama Group (Locs. T-1-3) andthe Kakegawa Group (Locs. K-1-3, 8-17).
The fauna is characterized by extinct, shallow,
warm-water species, such as Anadara castellata(Yokoyama), Glycymeris nakamurai Makiyama,
Amussiopecten praesignis (Yokoyama), Venericardia panda (Yokoyama), Suchium mysticum(Yokoyama), S. obsoletum (Makiyama), S.
suchiense (Yokoyama), Turritella perterebra
Yokoyama, Babylonia elata Yokoyama, Baryspira okawai (Yokoyama) and others. The three

Glossaulax species are most frequently found in
the Kakegawa Fauna (Table 1).
The Omma-Manganzi Fauna, cold-watermolluscs of Pliocene to early Pleistocene age,occurs in strata along the Japan Sea coast ofJapan that include the Omma Formation (Locs.
0-1-3). This fauna is characterized by extinct,
shallow, cold-water species, such as Anadara
amicula elongata Noda, Mizuhopecten tokyoensis hokurikuensis (Akiyama), Pseudamiantis
tauensis (Yokoyama), Suchium akitanum (Suzuki),. Turritella saishuensis Yokoyama and others.
Among the three Glossaulax species, only G.
hagenoshitensis is found in the Omma-Manganzi
Fauna (Table 1). Several warm-water species
are rarely associated with the Omma-Manganzi
Fauna (Ogasawara, 1981). This is considered tobe caused by the Paleo-Tsushima current, abranch of the warm-water Paleo-Kuroshio
current, which flowed into the Japan Sea
through Tsushima Strait at that time. The rareoccurrence of G. hagenoshitensis in the Omma
Formation is interpreted as having been influenced by this current.
The Kuroshio Fauna which flourishes in themodem warm waters under the influence ofKuroshio current first appeared in the early to
middle Pleistocene. G. hagenoshitensis and G.
nodai are found in the Kuroshio Fauna at theLoc. N-1 of the early Pleistocene Nojima Formation. Although the molluscan fauna of the Loc.
N-1 indicates shallow warm waters, it lacks any
characteristic species of the Kakegawa Fauna(Shikama and Masujima, 1969).

Descriptions of intraspecific variations of thethree Glossaulax species
Measurements. -Intraspecific variation withineach of the three Glossaulax species is bestshown by the differences in the shape of callosity.
To illustrate their variations, four values of thecallus were measured (Text-fig. 2): a is the
maximum width of the parietal callus, and b is
the maximum width of the umbilical callus; bothare measured normal to line 1 (Text-fig. 2) whichcoincides with the angulation developed along797.

Text-fig_ 2.

Measurementsof

Variation of Glossaulax (Gastropoda)

the three

Glossaulax species. a: Maximum width of parietal
callus. b: Maximum width of umbilical callus. I:

A line coinciding with angulation developed
along inner apertural margin. c: Length fromthe anterior end of umbilical callus to the apexof depression between parietal and umbilicalcalluses. d: Maximum width of adaxial half ofumbilical callus. W.: Width of shell. H.: Height ofshell. L.P.W.: Shell length perpendicular to W.
and H.
the inner apertural margin. However, somespecimens, especially G_ nodai and juvenile fonnof G. hyugensis, have not the distinctly developed
angulation. In such cases, the position of line I
is approximated. The value c is the length fromthe anterior end of umbilical callus to the apexof depression between the parietal callus andumbilical callus (sulcus) (Text-fig. 2)_ The value
d is the maximum width of the adaxial half of
the umbilical callus, and is measured nonnal toline c (Text-fig. 2)_
The values a, b, c and d are measured by thefollowing photographic method. (1) The parietal
and umbilical calluses are set almost parallel tothe film surface. (2) The specimen is photographed, and the phogoraphic print is enlarged(x2-x5). (3) The lines, a, b, c, d and I are drawn
on the print, and the lengths on the print, a',117b', c' and d', are measured. (4) The true values
a, b, C and d are calculated from the enlarged
print.
The intraspecific variations of the partie tal
and umbilical calluses are well illustrated by
the scatter diagrams of a and b (Text-figs. 3,4,5
and 6), and that of c and dlc (Text-fig. 7). The
intraspecific variations of the three Glossaulax
species are described below.
The variation of Glossaulax hyugensis(Shu to). -The specimens of G. hyugensis collected from Locs. M-1, M-2, M-3, T-1, T-2 andK-9 (Table 1) can be divided into three morphologically different groups (phenotypes lJ,
IT and I U) which occur together at Locs. M-1
and M-2 (Text-fig. 3), and T-2 (Text-fig. 4),
where they occur abundantly.
Phenotype lJ is a juvenile fonn (PI. 17, Figs.
Aa-Bb), with value a less than about 3 mm and bless than about 2 mm. Phenotype IJ is characterized by a wedge-shaped anterior lobe of parietal
callus which is developed along the posterior
margin of umbilicus, and by a subtrigonal umbilical callus. The anterior lobe of parietal callus
always protrudes more than the umbilical callus(a > b) and the fonner callus is attached to
the latter by a shallow groove.
Phenotype IT is a typical adult fonn (PI. 18,
Figs. Aa-Eb) and differs from phenotype lJ by
the shape of its umbilical callus. Phenotype IT
possesses a subquadrate umbilical callus. Phenotype lJ gradually changes to phenotype IT withgrowth (Text-fig. 7)_
Phenotype I U is an unusual adult fonn (PI.
18, Figs. Fa-Jb) characterized by having a very
weakly developed anterior lobe of parietal callus
and a subquadrate to semicircular umbilicalcallus. The umbilical callus has a shallow transverse groove at the center to posterior portion
but it may be indistinct. In phenotype I U, thedegree of protrusion of the parietal and umbilicalcalluses is almost equal (a = b). There are a few
intennediate fonns between phenotypes IT
and I U (PI. 18, Figs. Ka-b). In the scatter diagrams of a and b, the intermediate forms do notalways occupy their intermediate place (Loc. T-2
in Text-fig. 4).

Ryuichi MAJIMA

118

Loc. M-1

9o Glossaulax

o. !! Glossaulax
o Phenotype 3Ta

PI. 19. Fig.A• Phenotypes 3Ja ond 3Ua
1:1 intermediate form
- between phenotypes 3Ta and 3Ua

o

'i'l

5

o

PI.l8.Fig.F

b

00

o

.

q,0 0 '0o phenotype 3Ta

o

6

....

o
o

0

00::1

0

5

..

b

000 '80....
:...P:...l.l"'7.:...F"'i9::.:.M"--_ _0 0•o~,f is' '"

4

8

if/

0

:>0

o
o

6

hagenoshitensis (Shutci)

PI.18.Fig.K

hagenoshitensis (Shute)
8

N=6Loc. M-3mm

N = 95

cfle

'"~'"

I~ .:.P;cI.1~7.-!..F~igt.:.G"----i'oi'"i.on
eo !! - 'b. fl '"o4
PI.18.Fig.A"'.-"'=--_---'-=::c..:.=.:..

d:>

".,.

te- l;[;

P1.l7. Fig.C

"' ..

2

~ Glossaulax hyugensis (Shute)• 'of:." P1.17. Fig. A '" phenotypes 7J ond ITe.

'" Glossaulax hyugensis (Shute).. phenotype IU
A intermediate form between- phenotypes IT and IU'" phenotype IT

Ol+---r-~--~----~--.---~--~----~--._~

o

4

5

a 6

8

mm

Ol+---.---.---r---r---.-~'-~

o

10

3

a 4

5

6

mm

7

mm
8

B

Loc. M-2

N = 43o • Glossaulax hagenoshitensis (Shute)• phenotypes 3Ja and 3Ua

0>__---------'-P:;.:l.l.::9..:..F""g=.B

o

00

o

o

6

PI.1'Z Fig.H.

:..P.::.I..::'9~.F~ig1::'C,---_ _.-.,o

5

b

t!h

o

4

o

o

o

b

PI.18.Fig.B~~

4
PI.18.Fig.H

l'" "''''"'.--_--.:P....:I:.:.:.18'"-.F....:i:,;:g..::,C'" .. ~ Glossaulax hyugensis (Shute)
.J'

N =7

o Glossaulax hagenoshitensis (Shute)o phenotype 3Tao phenotype 3Ta6

Loc. T-1"' .. ~ Glossaulax hyugensis (Shute)'" phenotype IT'" phenotype IT.. phenotype IU.. phenotype IU

l;,J;;,. intermediate form between- phenotypes IT ond IU

intermediate form between
phenotype IT ond IU

OlfO--'--~--~-~4--~5-a-'6--r---r-~9-m-m--'0

3

a 4

6 mm

Text-fig. 3. Scatter diagrams of a and b (Text-fig. 2) for Glossaulax hyugensis (Shuto) and
G. hagenoshitensis (Shuto) at Locs. M-l, M-2, M-3 and T-l.

The variation of Glossaulax nodai, n. sp.The specimens of G. nodai collected from
Locs. M-5, K-13, K-17 and N-1 (Table 1) aremorphologically uniform (phenotype 2T: Pi.
18, Figs. La-Qb). They are characterized byhaving a wedge-shaped anterior lobe of parietal
callus and a subtrigonal umbilical callus. Pheno-

type 2T is morphologically similar to the phenotype 1J of G. hyugensis (PI. 17, Figs. Aa-Bb); theformer differs from the latter only in its greater
size (Text-fig. 7). The juvenile form of G. nodai
is unknown but it is likely to be morphologicallyalmost identical with the adult form (phenotype2T) judging from the callus form of the smallest

797.

Variation of Glossaulax (Gastropoda)

11

119

11

10

9

Loc. T-2

N = 28oLoc. K-l

10" .. f. Glossaulax hyugensis (Shuto)"phenotypes IJ and IT.. phenotype IU

o. q Glossaulax
o phenotype 3Tbform between
phenotypes IT and IUoo• phenotypes 3Jb and 3Ub() intermediate form betw!;'en- phenotypes 3Tb and 3Ub

8

.
..

PU8.Fig.1

o

o
0 0

g 0

o

o 0 00

o

o
o

CD

"
""
"f.
"

6

"

6

b

c.!t, ".

4ohagenoshitensis (Shuto)~ intermediateb

PI.19.Fig.L

N = 152

4

PI.18.F'g.D"'\~"_ _ _ _ _ _P-,-I.,--17-,-._Fi..egC.'--.B
O+----r----r----r---.----~--_.----r_--_r--~
8 mm 9
4
5

0

12

12

a

o

Loc. K-2

N = 31o • Glossaulax hagenoshitensis (Shuto)11o phenotype 3Tb10o• phenotype 3Ub

a 5

4

0

0
0

Loc. K-l0

11

N = 114o • ~ Glossaulax

hagenoshitensis (Shuto)oo phenotype 3Tb

100• phenotypes 3Jb and 3Ub

9betweenphenotypes 3Tb and 3Ub

0

6

0 00

o

6
o OOo~p

o

o

0

00
0

b

o

o

0
0

0

o

g

0

0

0

o

0

0

'(,

PU9.F,g.H

0

0

0 0

o

0

0

~ intermediate form

9

b

8 mm

6

0

o~ 0 000°e~0

0 0 0 ()

00

o

CS

0

PI.17.F'9· K
•

•

00

4

4

o
o
o

o

.., ..

.

P1.17. Fig.E•"~_ _ _ _ _ _ _ _-,-P-,-1.1-,-c,--F-,-,g~.~D

o

4

a 5

8

mm

9

0

4

a 5

8 mm 9Text-fig. 4. Scatter diagrams of a and b (Text-fig. 2) for Glossaulax hyugensis (Shu to ) at
Lac. T-2 and G. hagenoshitensis (Shuto) at Locs. K-l, K-2 and K-IO.

Ryuichi MAJIMA

120_PI_,ls-'-,F_ig"-,D_ _ _ _oLoc. K-12

o • Glossaulax hagenoshitensis (Shuto)o phenotype 3Ta0• phenotype 3Ub

6oLoc. K-17

N=6o

N = 52
PI.18,Fig,Q

6o\~_". :. P.:.:.:I.1.: :8, -,Fi" 9':. :.N

5

5

b

b

0

4

4

o 0
PI.1~ Fig,\

•

3
0

0"

o Qo

0

B

"""b

•

!l 0

O!l Glossaulax hagenoshitensis (Shuto)o phenotype 3Tb!l intermediate form between
phenotypes 3Tb and JUb"Glossaulax nodai n. sp.
" phenotype 2T
O+---.---r--~----r--'---r--~-­

o

3

a 4

6

O+--~--r-~--r_-~---r-~---._--._--~

7 mm

0

9

5

a 6

S

mm

6

4

,--,P1c.::,19::.:,F--"ig",.F_ _~rmm

Loc.K-13

Loc. K-8

N=4o Glossaulax hagenoshitensis (Shuto)o phenotype 3Tb

S mm 10N=12o Glossaulax hagenoshitensis (Shuto)o phenotype 3TaP1.18, Fig,L

6

'" 6

0

0

0

o

5

5

b

b
4

0

0

0

0

0
0
0
0

3

"Glossaulax nodai n. sp," phenotype 2T

OTO-~.---~--:----4r-a=-;5----6r---.---~8-m-m~S 0~0-~--r---.----4r-a-~5----.---.--~8.-m--m

Text-fig. 5. Scatter diagrams of a and b (Text-figs. 2) for Glossaulax hagenoshitensis (Shu to )at Locs. K-12 and K-8, and G. hagenoshitensis (Shuto) and G. nodai, n. sp. at Locs. K-17 and K-13.
specimen of phenotype 2T (Text-fig. 7).
The variation of Glossaulax hagenoshitensis(Shuto).-The specimens of G. hagenoshitensis
collected from 23 localities (Table 1) can bedivided into six morphologically different groups(phenotypes 3Ja, 3Ta, 3Ua, 3Jb, 3Tb and 3Ub).
They can be also divided into two allopatricgroups, one group comprising phenotypes 3Ja,

3Ta and 3Ua, and the other is phenotypes 3Jb,
3Tb and 3Ub. Phenotypes 3Jb, 3Tb and 3Ub
are characterized by a subsutural, minutely
incised band and a spiral ridge along the outermargin of the umbilical wall, while phenotypes
3Ja, 3Ta and 3Ua lack these characters (Textfig. 8). The latter phenotypes, however, rarely
possess a very weakly developed subsutural band

11
10

121

Variation of Glossaulax (Gastropoda)

797.

o
11

Loc. K-9

Loc. K-3

o Glossaulax hagenoshitensis (Shut 0)

o. \!. Glossaulax hagenoshitensis (Shuto)

10o phenotype 3Tao phenotype 3Tb• phenotype 3Jb

P119. Fig.Eoq intermediate form between

phenotypes 3Tb ond 3Jboo>-_ _ _ _...:.P..::I..:.::19::..:..F...:.i9>:.:.·1

PI.18.Fig.J

6

•

b

6

b

PI18.Fig.E

0

"

0

0

4

0

4

3

~.-_ _ _ _ _ _P...:.I.~17~.F...:.,g~.F" .. Glossau/ax hyugensis (Shuto)" phenotype IT.. phenotype IU

0~0---'--~~--r---~4~a~~--6r---~--~8-mm 01±0--~--~r---~--'4~a~5r---r-6--~--'----r9mm'\

6Loc. N-1

PI.19.Fig.M

PI.19.Fig.J

Loc. 0-1

N=6

"

•

4

b
3

6

N=6

PI. 18. Fig.O

o

4

b

o

o
o
o

•
o • Glossaulax hagenoshitensis (Shu to)2• phenotype 3Tb
o phenotype 3Ub'0o Glossaulax hagenoshitensis (Shu to)

Glossaulax nodai n.sp.

'0 phenotype

2T

3

4

o phenotype 3Tb

oto---:---:---:--~~-,--~----r---~ 0t---,---,---,----r~~--~---r---r--~--

a 5

6

8mm

0

4

a 5

6

8

9mm

Text-fig. 6. Scatter diagrams of a and b (Text-fig. 2) for Glossaulax hyugensis (Shuto) and
G. hagenoshitensis (Shuto) at Loc. K-9, G. hagenoshitensis (Shuto) at Locs. K-3 and 0-1, andG. hagenoshitensis and G. nodai, n. sp. at Loc. N-l.

(PI. 17, Fig. Ha) and a spiral ridge of the umbilical wall. In the localities where specimens
occur abundantly, all the phenotypes 3Ja, 3Ta
and 3Ua occur together at Locs. M-1 and M-2(Text-fig. 3) and all the phenotypes 3Jb, 3Tb
and 3Ub at Locs. K-1 and K-10 (Text-fig,4).

Phenotypes 3Ja (PI. 17, Figs. Ca-b) and 3Jb(PI. 17, Figs. Da-Fb) are juvenile forms smaller
than about 2 mm for values a and b. They arecharacterized by the possession of a wedge-shaped
anterior lobe of parietal callus and a subquadrate
umbilical callus. The parietal callus protrudes

Ry uichi MA JIMA

122

0.3

0.2

die

0.1

Glossaulax nodai n. sp.

O+-__~__~____r -_ _~_ _~_~~~_ _~_ _~_ ____
1

2

3

4

5

e 6

7

8

9

mm

T ext-fig. 7 . Scatter diagram of c and di e (Text -fig. 2 ) for phe noty pe 3Jb o f Gl ossaulax
hagenoshitensis (Shuto) (black circle : Loc . K-10) , phenotypes 1J a nd 1 T of G. hyugensis (Shuto)(white triangular: Loc. M-1) and G. nodai, n . sp. (black reverse triangular: Loc . K-13; white reverse
triangular : Loc. K-17).

somewhat more than the umbilical callus (a ~b), and the former is attached to the latter witha shallow groove. The shape of callosity issimilar to that of the phenotype lT of G. hy u-

gensis, but phenotypes 3Ja-b (3Ja + 3Jb) differ
from phenotype lT in the small size (Text-fig. 7),
and in the sub sutural and umbilical wall sculpture of phenotype 3Jb.

797. Variation of Glossaulax (Gastropoda)

Phenotype 3Ta

Phenotype 3Tb
Text-fig. 8 . Sculpture of subsutural a rea
and umbilical wall margin of phenotypes 3Ta
a nd 3 Tb of Glossaulax hagenoshitel1sis(Shu to ), cha racter izing two allopatric forms.
Populations including phenotypes 3Jb, 3Tb
and 3Ub are distinguished from those includin g ph enotypes 3Ja, 3Ta and 3Ub by hav ing
a subsutural, minutely incised band and a
wea k to strong spiral ridge along the umbilica l wall m argin.

Phenotypes 3Ta (PI. 17, Figs. Ma-c , PI. 18 ,Figs. Pa-b, PI. 19, Figs. Aa-Fc) and 3Tb (PI.
18, Figs. Qa-c, PI. 19, Figs. Ga-Mc) are ty picaladult forms. They are characterized by having aprominent anterior lob e of parietal callus and asemicircular to tongue-like umbilical callus. In
some specimens, the anterior lob e of parietal
callus is indistinct (PI. 18, Figs. Pa-b). The umbilical callus usually protrudes more than theparietal callus (a < b); the former callus isseparated from the latter by a narrowly tobroadly rounded sulcus. There is a shallow transverse groove on the umbilical callus at its posterior portion but the groove disappears in some
spec imens. Phenotypes 3Ta-b (3Ta + 3Tb) aresimilar to the phenotype 1 U of G. hy ugensis but
differ slightly from the latter by having astronger funicle and a rather deep sulcus.
Phenotypes 3Ua (PI. 17, Figs. Ha-Ic) and123

3Ub (PI. 17 , Figs. Ja-Kc) are unusual adultforms. Th ey are characterize d by having a wedgeshaped anterior lobe of parietal callus and aprominently swollen subquadrate umbilical callus.
The degree of protrusion of the parietal callus isalmost th e sam e as that of the umbilical callus(a = b) . Phenotypes 3Ja and 3Jb graduallychange with growth into phenotypes 3Ua and
3Ub, respectively. There are a few intermediate
fonns between phenotypes 3Ta and 3Ua (PI. 17 ,Figs. Ga-c: the holotype of G. hagenoshitensis),an d also between 3Tb and 3Ub. In the scatter
diagrams of a and b, the intermediate forms between phenotypes 3Tb and 3Ub do not always
occupy their intermediate place (Loc. K-1 in
Text-fig . 4). The shape of the callosity of ph eno types 3Ua-b (3Ua + 3Ub) is very similar to thatof phenotype iT of G. hyugensis, but the umbilical callus of the former phenotypes is relatively larger than the latter. The umbilical opening ofphenoty pes 3Ua-b is , therefore, more slenderthan in the ph enoty pe 1T of G. hyugensis.
Discussion on intraspecific variations of thethree Glossaulax species
From the analysis of variations of the callus
morphologies of the three Glossaulax species,
their intraspecific variations have been reconstructed and summarize d (Text-fig. 9). G. hyuge nsis and G. hagenoshitensis show " dimorphic " variation s in their adult stages, which aremorphologically very similar to each other, but
G. nodai does not show such variation . The
follo wing discussions are based upon two assumptions that (1) the mortality rates of thethree species did not extremely different among
the growth stages, and that (2) the fossil population from each locality did not undergo selective
post-mortem t ransportation. The rarity of thejuvenile form observed in Loc. M-2 (Text-fig.
3), Locs . K-1 and K-2 (Text-fig. 4), and Locs.
K-17 and K-8 (Text-fig. 5), is due to that someor many juvenile forms are artificially damaged
during the collection at some localities wherefragile spec imens occur, and to that juvenile
form may be overlooked at some localities

Ryuichi MA JIMA

124

Glossaulax nodai n. sp.

Glossaulax hyugensis (Shute)

"""
"""

QQ'VV<;Jbb

V'V 99 '0

QQ'ilQ?

'OQ"'Q

"""""
"
""
"
"""
""

phenotype /J

OL-----~--~---a=-----~-------- oL-------------~a~--------------

hagenoshitensis (Shute)bText-fig. 9 . Summary of ontogenetic variations of the umbilical parts of Glossaulax
hyugensis (Shuto), G. nodai, n . sp ., and two allopatric forms of G. hagenoshitensis (Shuto) . Pheno type symbols are the same as in Text-figs . 3,4, 5 and 6. The variation range of a and b of eachphenotype is approximately illustrated, and the number of each symbol does not mean the frequency.

797.

Variation of Glossaulax (Gastropoda)

where the species is rare.
Intraspecific variation of the callus morphology within the three Glossaulax species
also plays important roles in specific differentiation.-The phenotypes lJ, IT and I U of
G. hyugensis correspond ontogenetically withthe phenotypes 3Ja-b, 3Ua-b and 3Ta-b of
G. hagenoshitensis, respectively. In the adult"dimorphic" variations of the two species,
frequency of the phenotype IT (1 U) of G.
hyugensis is much greater (smaller) than thatof its corresponding phenotypes 3Ua-b (3Tab) of G. hagenoshitensis (Text-figs. 3, 4, 5 and
6). The two species are easily distinguished fromeach other by the difference of the frequency
between ontogenetically corresponding adultphenotypes.
G. nodai resembles phenotypes lJ and IT of
G. hyugensis, and also phenotypes 3Ja-b and3Ua-b of G. hagenoshitensis. However, intra·
specific variation within G. nodai shows only
one form throughout growth, which is quitedistinct from the adult "dimorphic" variationsof both G. hyugensis and G. hagenoshitensis.
The two allopatric forms of G. hagenoshitensis, which are divisible by the sculpture of
subsutural area and umbilical wall margin(Text-fig. 8), show analogous variations in the
shapes of parietal and umbilical calluses (Textfig. 9). I consider the two allopatric forms of
G. hagenoshitensis to be environmentally controlled, and to be interpopulational variation
within a single species, regarding their corresponding parietal and umbilical callus variations
as a species character.
The "dimorphic" variations represented by
the adult pnenotypes IT and I U of G. hyugensis,
and 3Ta-b and 3Ua-b of G. hagenoshitensis
are not expressions of sexual dimorphism.-If
the growth points, which show the first appearances of the unusual adult form (phenotype I U)
of G. hyugensis and the typical adult form
(phenotypes 3Ta-b) of G. hagenoshitensis in
their growth series (Text-figs. 3, 4 and 9), wereinterpreted as representing the stages of sexual
maturity, their "dimorphic" variations might
represent sexual dimorphism. However, I do not125

consider the "dimorphic" variations of the two
species to be sexually controlled. The frequencyof the phenotype IT (1 U) to all adult shells of
G. hyugensis is much greater (smaller) thanthat of its ontogenetically corresponding phenotypes 3Ua-b (3Ta-b) to all adult shells of G.
hagenoshitensis at some localities where theyoccur abundantly (Text-figs. 3 and 4). If the"dimorphic" variations of the two species wereregarded as sexual, ontogenetically correspond.
ing phenotypes (1T and 3Ua-b; IU and 3Tab) would represent the same sex, and one could
hardly explain the fact that the frequency of thecorresponding phenotypes of the two species
are extremely different, and that phenotypes
3Ua-b lack the specimens comparable in sizewith the larger specimens of phenotype IT(Tables 2 and 4). The different frequency is notenvironmentally controlled because the two
species sympatrically occur at Locs. M·1, M·2,
M·3, T·1 and K·9 (Text.figs. 3 and 6; Table 1).
Comparable morphologies between juvenile
and adult forms among the three Glossaulax
species are interpreted as heterochrony.-A
heterochronic model is proposed to explain
why G. nodai does not show such "dimorphic"
variation as G. hyugensis and G. hagenoshitensis
show, why ontogenetically corresponding adultphenotypes between G. hyugensis and G. hageno·
shitensis possess extremely different frequency,
and why the adult phenotypes 3Ua-b of G.
hasgenoshitensis lack the specimens comparable
in size with the larger specimens of phenotypes
3Ta-b. The term "phenotype" in the following
lines are used in the same sense as growth stage
as noted in the chapter of introduciton.
In this model, an imaginary ancestral speciesof the three Glossaulax species is presumed(Text·fig. 10). All individuals of this imaginary
ancestral species pass through the three different
growth stages represented by three phenotypes,
J (juvenile), I (intermediate) and A (adult) ingrowth order. In the shapes of parietal andumbilical calluses, phenotypes J, I and A corre·
spond, respectively, with phenotypes lJ (G.
hyugensis) and 2T (G. nodai) , phenotypes IT(G. hyugensis) and 3Ja-b (G. hagenoshitensis),Ryuichi MAJIMA

126

Imaginary ancestral
speciesGlassaulax nadai

Glassaulax hyugensis

Glassaulax hagenashilensis

Paedomorphocline?

. -I

Paedomorphosls

N t..
L _ _ _e_o_e_n_y_ _ _ _ _~~-:__----~

Pre-displacement. Acceleration

Text-fig. 10. A model of ontogenetic development and heterochrony of Glossaulax hyugensis(Shuto), G. nodai, n. sp., and G. hagenoshitensis (Shuto). Mode of the ontogenetic development ofeach species, which is given by the black column(s), is illustrated as comparable with the individual
distribution of each phenotype plotted in the scatter diagrams of a and b (Text-figs. 3, 4,5 and 6).
The width of each column illustrates the frequency of each phenotype. In this model, an imaginary ancestral species of the three Glossaulax species is presumed, and all its individuals passthrough the three growth stages which are morphologically represented by phenotypes, J, I and
A in growth order. Phenotypes J, I and A morphologically correspond, respectively, with phenotypes 1 J and 2 T, phenotypes 1 T and 3Ja-b, and phenotypes 1 U and 3 Ta-b. The timing of theonset of the development from phenotype I to phenotype A slightly varies with the individual, in
which the two critical growth stages a and {3 are recognized and defined, respectively, as the stages
where the smallest and largest individuals of phenotype I begin their development toward phenotype A. The short vertical arrows between the two columns exhibit the development, from phenotype I to phenotype A, of the individuals. The critical growth stage a' of G. hyugensis, and aU
and {3" of G. hagenoshitensis are literally corresponding with the critical growth stages a and {3of the imaginary ancestral species as given by the oblique or horizontal arrows. The mode of the
ontogenetic development of G. hyugensis, G. nodai and G. hagenoshitensis can be explained byheterochronic evolution from this imaginary ancestral species.

and phenotypes 1 U (G. hyugensis) and 3Ta-b(G. hagenoshitenis). Phenotype J graduallychanges into phenotype I with growth but
phenotype I relatively rapidly changes into
phenotype A. T4e timing of the onset of thedevelopment from phenotype I to phenotype
A slightly varies with the individual, in which
two critical growth stages are recognized: one(stage a) is defined as the stage for the smallest
individual to begin its development from I to
A, and the other (stage (3) is the stage for thelargest one.
In Text-fig. 10, the mode of the growth of
the imaginary ancestral species is given by two
black columns. Phenotypes J and I are represented by one short column but phenotype
A has the other long column. Individuals ofeach phenotype grow from base to top of eachcolumn. Short vertical arrows between the twocolumns exhibit the rapid development fromphenotype I to phenotype A in individuals.
The width of the column illustrates the fre-

797.

Variation of Glossaulax (Gastropoda)

quency of each phenotype. The critical growthstages a and (3 therefore coincide, respectively,
with the right and left corners of the top of thecolumn of phenotypes J and I. The equivalent
explanations apply to the columns of G.
hyugensis, G. nodai and G. hagenoshitensis(Text-fig. 10). The columns in Text-fig. 10 are
illustrated as comparable with the individual distribution of each phenotype plotted in the
scatter diagrams of a and b (Text-figs. 3, 4, 5
and 6).
Among the three Glossaulax species which
overlap stratigraphically and geographically, G.
hyugensis occurs in the oldest strata. Shuto(1964) recorded G. hyugensis from the firstfossil horizon (late Miocene) of the MiyazakiGroup. G. nodai and G. hagenoshitensis, on theother hand, first appeared in late Pliocene
strata (Table 1).
Glossaulax hyugensis is thought to have
evolved from the imaginary ancestral species
by paedomorphosis. Paedomorphosis is themorphological expression which is observedin phylogeny as the retention of ancestral juve.
nile characters by later ontogenetic stages ofdescendants (Gould, 1977). Ontogeneticallycorresponding critical growth stage between theimaginary ancestral species and G. hyugensis isgiven by an arrow (a -+ a') in Text-fig. 10. The
adult stage of G. hyugensis does not largely reachthe critical growth stage (3 of the imaginary
ancestral species, and many specimens of phenotype IT, as the result of the paedomorphosis,
remain without the onset of the development
toward phenotype 1 U. This is the reason why G.
hyugensis possesses larger numbers of phenotype
IT than phenotype 1 U.
Glossaulax nodai is thought to have evolved
from G. hyugensis by paedomorphosis. The adultstage of G. nodai never reaches the critical
growth stage a' (Text-fig. 10) of G. hyugensis.
In other words, all of phenotype 2T, as theresult of paedomorphosis, remain without theonset of the development toward the "nextstage". This is the reason why G. nodai does
not show such "dimorphic" variation as G.
hyugensis and G. hagenoshitensis show.

127

Glossaulax hagenoshitensis is thought to have
evolved from G. hyugensis by peramorphosis.
Peramorphosis (Alberch et al., 1979) is themorphological expression which is observed inphylogeny as the repetition of ancestral adultstages in embryonic or juvenile stages of descendants (Gould, 1977). The critical growthstage (3" (Text-fig. 10), which is shown by thelargest individuals of phenotypes 3Ua-b of G.
hagenoshitensis, ontogenetically correspondswith the critical growth stage (3 of the imaginary
ancestral species «(3 -+ (3" in Text-fig. 10). In
other words, all the individuals of phenotypes
3Ua-b, as the result of peramorphosis, havealready begun their development toward phenotypes 3Ta-b until the critical growth stage (3".
This is the reason why G. hagenoshitensis possesses larger numbers of phenotypes 3Ta-b than
3Ua-b, and why phenotypes 3Ua-b lack the
specimens comparable in size with the larger
specimens of phenotypes 3Ta-b.
As McNamara (in press) has summarized,
the comparison of the rates of the developmentof characters, and of tdult sizes between heterochronic ancestor and descendant play importantroles as keys to the identification of heterochronic processes in fossil material.
Glossaulax nodai is considered to have evolved
from G. hyugensis by neotenic process. Neoteny
is a reduced rate of morphological development
during the juvenile phase, which results in amorphologically retarded adult (McNamara inpress). The adult of paedomorph G. nodai(attaining 50.0 mm in height, Table 3) is larger
in size than that of apaedomorph G. hyugensis(attaining 36.3 mm in height, Table 2). In
neotenic process, the descendant adult is often
larger in size than the ancestral adult due todelayed onset of sexual maturity.
Glossaulax hagenoshitensis is considered tohave evolved from G. hyugensis by the combination of pre-displacement and acceleration. The
peramorph G. hagenoshitensis begins its "postlarval" ontogeny with subquadrate umbilicalcallus (phenotypes 3Ja-b) which morphologicallycorresponds with that of the adult phenotype
IT of aperamorph G. hyugensis. This process

128

Ryuichi MAJIMA

is interpreted to be pre-displacement (Alberch
et al., 1979), which is the initiation of development of one or a number of organs or structures of the descendants at a relatively earlier
stage of development of the whole organism,with respect to the ancestor (McNamara inpress). Relatively larger umbilical callus ofphenotypes 3Ua-b of peramorph G. hagenoshitensis reasonably supports this interpretation.
On the other hand, the majority of individualsof phenotypes 3Ja-b and 3Ua-b of G.
hagenoshitensis begin their morphological development toward phenotypes 3Ta-b at a smaller
size. This is inferred from the individual distribution of G. hagenoshitensis plotted in the
scatter diagrams of a and b (Text-figs. 3 and 4):that is, the population of G. hagenoshitensis
already possessed relatively larger numbers ofphenotypes 3Ta-b than 3Ua-b at the stage
where phenotypes 3Ta-b first appeared in thegrowth series. This fact may be explained by
the acceleration of the rate of development in
the early ontogenetic stage of G. hagenoshitensis.
Acceleration is an increase in the rate of morphologicaldevelopment during on togeny(McNamara in press). Alberch et al. (1979)
believed that it is possible for the combinationof peramorphic processes to be operating concurrently in a single species.
In the acceleration process, the descendant
adult is often smaller in size than the ancestral
adult due to acceleration in the onset of sexual
maturity. However, it is difficult to compare
absolutely the size of G. hyugensis with that of
G. hagenoshitensis. The largest individual ofphenotype 3Ta (attaining 34.5 mm in height,
Table 4) is smaller than that of phenotype 1 U(36.3 mm) of G. hyugensis, but phenotype
3Tb (attaining 46.6 mm in height, Table 4) islarger than the latter species. Odhner (1913)
and Marincovich (1977) reported the shell sizeof Cryptonatica clausa (Broderip and Sowerby),a common boreal naticid, varies in accordancewith different environments_ In the acceleration
process of the evolution from G. hyugensis to
G. hagenoshitensis, therefore, it is not known
whether the onset of sexual maturity is also

accelerated.
If G. hyugensis evolved from the imaginary
ancestral species by neoteny, the paedomorphic
lineage: the imaginary ancestral species -+ G.
hyugensis -+ G. nodai (Text-fig. 10) may beinterpreted as a paedomorphocline (McNamara,1982). The evolution of G. hagenoshitensis,
which is considered to have evolved from G.
hyugensis by peramorphosis, seems to be inconsistent with the heterochronic clinal modelof McNamara (1982), who discussed the difficulty of reverse speciation along a heterochronic cline. However, if the imaginary ancestral species was extinct, there is the possibility
that the peramorph G. hagenoshitensis did
evolve from the paedomorphocline. This is able
to have occurred if the niche, which previously
had been occupied by the imaginary ancestral
species, became empty. There was thus noeffective block (competitive exclusion) toreverse speciation.
As is well known, naticids prey on the infaunal mollusks, especially bivalves. If thethree Glossaulax species prey on different
mollusks inhabiting different substratum depth,
the environmental gradient along which the
paedomorphocline and one peramorphosis (Textfig. 10) have developed, may be considered
to be difference in depth of their preys. This
interpretation may allow the apparently sympatric occurrences in the heterochrony among
the three Glossaulax species: that is, paedomorph
G. nodai and peramorph G. hagenoshitensis
occur together at Locs. K-13, K-17 andN-1, and aperamorph G. hyugensis and peramorph G. hagenoshitensis occur together at
Locs. M-1, M-2, M-3, T-1 and K-9 (Table 1).
Systematic paleontology
Family NATICIDAE Forbes, 1838
Subfamily POLINICINAE Finlay andMarwick, 1937
Genus Glossaulax Pilsbry, 1929
Type species.-Natica reclusiana Deshayes,
1839, by original designation.

797.

Variation of Glossaulax (Gastropoda)

Glossaulax hyugensis (Shuto, 1964)
PI. 17, Figs. Aa-Bb, PI. 18, Figs. Aa-Kb.
Polinices (Glossaulax) hyugensis Shuto, 1964,

p. 282-284, pI. 42, figs. 3, 5,13,15, pI. 43,
figs. 9, 10, 12, text-figs. 1, 2.
Not Polinices cfr. hyugensis Shuto: Suehiro,
1979, p. 89, pI. 16, figs. 2a--b [=Glossaulax
didyma coticazae (Makiyama, 1926)].
Polin ices (Glossaulax) aff. reiniana (Dunker):
Shuto, 1964, p. 285-286, pI. 42, fig. 1, textfig. 3 [not P. (G.) reiniana (Dunker, 1877)].
Holotype.-GK. L8009 (PI. 18, Figs. Aa-b),
from the fourth fossil horizon of Shuto (1961),
the late Pliocene to early Pleistocene Takanabe
Member of the Koyu Formation (Loc. M-1).
Revised diagnosis. -Medium-sized and globose
to weakly elongate shell characterized by aspiral angulation dividing the base and theumbilical wall, almost flat umbilical wall, weakfunicle, and by showing three forms of callosity(Text-fig. 9).
Juvenile form (phenotype lJ: PI. 17, Figs.
Aa-Bb): Anterior lobe of parietal callus wedgeshaped and covering posterior margin of umbilicus; umbilical callus subtrigonal and attachedto parietal callus with a shallow groove.
Typical adult form (phenotype IT: PI. 18,
Figs. Aa-Eb): Shape of anterior lobe of parietal
callus almost identical with juvenile form but
umbilical callus subquadrate.
Unusual adult form (phenotype 1 U: PI. 18,
Figs. Fa-Jb): Anterior lobe of parietal callus
very weak to nearly lacking; umbilical callus
subquadrate to semicircular with a weak toindistinct transverse groove at its central toposterior portion.
Description. -Shell moderate in size and in
thickness, globose to weakly elongate in form;
body whorl greatly inflated; shoulder slightly
concave; nuclear whorls 1-1/2, smooth, separated
from the first conch whorl by a weak groove;
postnuclear whorls 2-1/2 in holotype, almost
occupied by body whorl. Spiral sculpture of
microscopic, closely spaced, minutely wavy
costellae, and of very weak subsutural ridge

129

which is most distinct in early conch whorls
and starts from the second one; axial sculptureof incremental growth lines that are most distinct
at base. Parietal callus moderately thick, moderately filling posterior apertural angle; anterior
lobe very strong, wedge-shaped (phenotypes
lJ and IT), or weak to nearly lacking (phenotype 1 U). Umbilicus broadly and deeply open,
horn-like form, deeply excavating anterior inner
lip of aperture; umbilical callus subtrigonal(phenotype lJ) to sub quadrate (phenotypeIT), or subquadrate to semicircular (phenotype
1 U); funicle weak. Umbilical wall almost smooth
except for incremental growth lines and reliable
number of spiral striae, separated from the baseby an acute (phenotype lJ) to subacute (phenotypes 1T and 1 U) angulation. Posterior inner
margin of aperture distinctly angulate but weakly
rounded in juvenile specimens (phenotype lJ);
anterior inner lip and outer lip thin except for
gradually thickening anteriorly; basal lip weakly
thickened.
Remarks. -The measurements of the largest
specimen of G. hyugensis from each locality are
given in Table 2.
Glossaulax didyma didyma (Roding), common in Japanese Pliocene to Recent warm tocold waters, is similar to the unusual adult form
(phenotype 1 U) of G. hyugensis, but the former
species differs from the latter in having arounded base and an umbilical wall sculptured
with a very shallow bu t wide spiral depression
around the funicle. Additionally, G. didyma
didyma has a variant which has been called G.
hosoyai (Kira) by Japanese malacologists. The"G. hosoyai"-type individual of G. didyma
didyma is characterized by having a very stout
shell and an umbilicus almost closed by a heavy
and large umbilical callus, similar to what someprevious workers have recognized as a form of
G. reclusiana (Deshayes) (G. reclusiana imperforata (Dall): see pI. 29, fig. 7 of Marincovich,1977). Therefore, the two species are also
distinguished from each other by their rangesof variations.
Glossaulax reiniana (Dunker) (PI. 17, Figs.
Oa-b), common in the Japanese late Pliocene toTable 2.

Measurements (in mm) of the largest specimens ofphenotypes iT and i U of Glossaulax hyugensis (Shuto)
at each locality. Abbreviations are shown in Text-fig. 2
except for N. W. (Number of whorls).

Loe.

W.

L.P.W.

H.

M-1

39.8
23.3+
15.6+
25.6
33.5+
24.5+

30.3
18.4
14.4
20.8
29.1
22.0

32.6+
20.7
ca.15.5
20.7+
32.2+
20.5

M-2
M-3

T-1
T-2
K-9

Loc.
~1-1

M-2
14-3

Phenotype 1T

N.W.

Specimen

5+
4.5+
4.5
4.5+
5+
4.5+

IGUT no.
IGUT no.
GIYU no.
IGUT no.
IGUT no.
IGUT no.

15699-40
15701-20
571-1
15691-2
15693-1
15716-2

Phenotype lU

T-1
T-3
K-8
K-9
K-12

W.

L.P.W.

H.

N.W.

M-1

30.5+
ca.38.7
17.0+
33.9+
ca.33.8

25.8
32.2
15.2
30.4
26.8

30.1
36.3
16.1
33.0
22.6+

3.5+
4.5+
2.5+
5.5
2.5+

M-2
T-1
T-2
K-9

IGUT no.
IGUT no.
IGUT no.
IGUT no.
IGUT no.

15699-48
15701-28
15691-6
15694-26
15716-3*

Measurements (in mm) of the largest specimen of
phenotype 2T of Glossaulax nodai, n. sp. at each locality.
Abbreviations are shown in Text-fig. 2 except for N. W.
(Number of whorls).
Phenotype 2T

W.

M-5

49.9
40.9
28.2+
20.5+

41.4

K-13
K-17

N-1

32.3
27.3
22.4

H.

N.W.

50.0
36.4
27.3+
23.6+

4.5+
6

5.5
4+

'Holotype

Table 4.

H.

N.W.

29.8
17.4+
29.6
25.5
17.9
37.4
28.3+
ca.31. 5

24.8
17.3
23.3
20.0
13.9
33.0
26.2
27.2

29.0
18.3
24.5
22.8+
15.1
34.5
ca.28.6
ca.29.7

4.5+
4.5
4.5+
5+
5
5+
4.5+
4.5+

Specimen

IGUT no.
IGUT no.
GIYU no.
IGUT no.
IGUT no.
IGUT no.
IGUT no.
IGUT no.

15700-43
15702-13571-715690-1
15692
15714-14
15715-2
15712-8

Loe.

w.

L.P.W.

H.

N.W.

Specimen

M-1
M-2

17.3+
19.8
12.8

12.9
15.0
10.3

15.5
16.2
11.2

4.5+
3.5+
4+

IGUT no. 15700-21
IGUT no. 15702-10
IGUT no. 15712-3~

Specimen

IGUT no.
IGUT no.
IGUT no.
GIYU no.

15698"
15695'
15697-5"563**"ParatypeMeasurements (in mm) of the largest specimens ofphenotypes 3Ta, 3 Ua, 3 Tb and 3 Ub of Glossaulax
hagenoshitensis (Shuto) at each locality. Abbreviations
are shown in Text-fig. 2 except for N. W. (Number ofwhorls).

'<;::Phenotype 3Tb

C:;.

Loc.

W.

L.P.W.

H.

N.W.

M-4

0-1
0-2
0-3

28.0
29.6+
40.1
45.5
44.0
38.1+
36.9
32.3+
24.2+
30.2+
35.8+
30.3+
28.7
15.6+
16.7

23.6
27.0
31.1
38.3
37.8
33.3
32.3
28.8
24.9
25.3
31. 7
24.5
23.5
13.4
13.3

19.6+
27.3+
35.2
46.6
42.7
32.0
34.5
22.8+
22.2
25.2+
36.1
ca.27.0
28.5
11.7+
14.1

4+
5+
5+
4+
4.5+
4.5+
5+
4.5+
4.5+
4.5+
4+
3.5+
3.5+
5
5

Loc.

W.

L.P.W.

H.

N.W.

K-1
K-2
K-10
K-11

22.0
18.0
23.1
14.7+
17.6+

16.0
13.5
18.4
12.9
15.3

16.3
13.5
18.1
11.9
17.0

4+
4.5+
4.5+
4+
4.5

K-3
K-1
K-2
K-10
K-11
K-13
K-14
K-15
K-16
K-17

N-1
Loc.

L.P.W.

L.P.W.

Specimen'Slightly deformed

Table 3.

oW.

Phenotype 3Ua

K-12
Loe.

....
tIO

Phenotype 3TaSpecimen

GK.
IGUT no.
IGUT no.
IGUT no.
IGUT no.
IGUT no.
IGUT no.
IGUT no.
IGUT no.
IGUT no.
IGUT no.
GIYU no.
IGUT no.
IGUT no.
IGUT no.

L7987
15717-17
15703-122
15704-47
15705-116
15707-1
15713-3
15709-5
15710-5
15711-14
15706-48
567-3
15688-1
15718-2
15689

Phenotype 3Ub

N-1

Specimen

IGUT no.
IGUT no.
IGUT no.
IGUT no.
GIYU no.

15703-59
15704-13
15705-56
15707-5
567-2

-.

~

~
~

~

797.

Variation of Glossaulax (Gastropoda)

Recent warm waters, is similar to the juvenile(phenotype lJ) and typical adult (phenotypeIT) forms of G. hyugensis, but the former
species is distinguished from the latter in having
an umbilical wall sculptured with a deep spiralgroove around the funicle.
Glossaulax nodai, n. sp.
PI. 18, Figs. La-Qb.
Holotype.-IGUT no. 15695 (PI. 18, Figs. Lab), from the late Pliocene Dainichi Member ofthe Lower Kakegawa Formation (Loc. K-13).
Paratypes.-IGUT no. 15698 (PI. 18, Figs.
Ma-b) , from the sixth fossil horizon of Shuto(1961), the late Pliocene to early Pleistocene
Takanabe Member of the Koyu Formation (Loc.
M-5); IGUT nos. 15696-1-2, from the same
locality as the holotype (Loc. K-13); IGUT nos.
15697-1-1) (PI. 18, Figs. Na-b), from the same
member as the holotype (Loc. K-17); GIYU nos.
562, 563 (PI. 18, Figs. Qa-b) and 564, from theearly Pleistocene Nojima Formation (Loc. N-1).
Etymology. -This species is named for Professor Hiroshi Noda of Institute of Geoscience,
University of Tsukuba, who introduced thepresent writer to the paleontology of the
Naticidae.
Diagnosis. -Medium-sized and globose shellcharacterized by a spiral angulation dividing thebase and the umbilical wall, almost flat umbilicalwall, weak funicle and by one form of callosity(Text-fig. 9). Anterior lobe of parietal callus
wedge-shaped, developing along posterior marginof umbilicus; umbilical callus subtriangularand attached to parietal one with a weak toindistinct groove.
Descrip tion. -Shell moderate in size and in
thickness, globose in form; body whorl greatly
inflated; shoulder slightly concave; nuclear
whorls 2-1/2, smooth, separated from the firstconch whorl by a weak groove; postnuclear
whorls 3 in holotype, almost occupied by bodywhorl; suture moderately impressed. Spiralsculpture of microscopic, closely spaced, minutely wavy costellae, and of very weak ridge at
subsutural part which starts from the second131conch whorl and changes into two or three weakcostellae in later whorls of larger specimens;
axial sculpture of incremental, prosoclinal
growth lines that are most distinct at base.
Parietal callus moderately thick, moderately
filling posterior apertural angle; anterior lobe
very strong, wedge-shaped. Umbilicus broadly
and deeply open, horn-like form, and deeply
excavates anterior inner lip of aperture; umbilical callus weakly developed, subtrigonal inform; funicle weak to indistinct; umbilical wallalmost smooth except for incremetal growthlines and many spiral striae, separated from thebase by a subacute angUlation. Posterior inner
margin of aperture weakly rounded; anterior
inner lip and outer lip thin except for gradually
thickening anteriorly; basal lip weakly thickened.
Remarks. -The measurements of the largest
specimen of G. nodai from each locality are
given in Table 3. There are no species comparablewith G. nodai except for G. hyugensis andG. hagenoshitensis. G. nodai is easily distinguished from G. hyugensis and G. hagenoshitensis
by the range of morphological variation (Textfig. 9).
Glossaulax hagenoshitensis (Shuto, 1964)
PI. 17, Figs. Ca-Kc, Ma-c,
PI. 18, Figs. Pa-Qc, PI. 19, Figs. Aa-Mc.
Polinices (Neverita) sagamiensis Pilsbry: Shuto,
1964, p. 281-282 [in part], pI. 42, fig. 2[not P. (N.) sagamiensis Pilsbry, 1904; not
pI. 42, figs. 8 and 14, showing imperfectspecimens] .
Polinices sagamiensis Pilsbry: Itoigawa andShibata in Morishita, 1977, pI. 30, fig. 18[not P. sagamiensis Pilsbry, 1904].
Po lin ices (Glossaulax) hagenoshitensis Shuto,
1964, p. 284-285, pI. 42, fig. 10, text-fig. 1.
Neverita (Glossaulax) reiniana (Dunker): Kaseno
and Matsuura, 1965, pI. 2, figs. 32, 33 [notN. (G.) reinialla (Dunker, 1877)].

Holotype.-GK. L8003 (PI. 17, Figs. Ga--c) ,from the fourth fossil horizon of Shuto (1961),
the late Pliocene to early Pleistocene Takanabe
Member of the Koyu Formation (Loc. M-1).

132

Ryuichi MAJIMA

Revised diagnosis.-Medium-sized and globose
to globose elongate shell characterized by a spiralangulation dividing the base and the umbilicalwall, strong funicle, and by showing two allopatric (Text-fig. 8) and three sympatric (Textfig. 9) forms. Two allopatric forms: One form
possesses a very weakly developed sub suturalspiral ridge which is most distinct in early conch
whorls, and a flat umbilical wall (phenotypes
3Ja, 3Ta and 3Ua); the other form has a subsutural, minutely incised band and a strong to
weak spiral ridge along the outer margin of theumbilical wall (phenotypes 3Jb, 3Tb and 3Ub)
(Text-fig. 8). Three sympatric forms, characterized by shapes of parietal and umbilical calluses,
are as follows:
Juvenile form (phenotypes 3Ja-b: PI. 17, Figs.
Ca-Fb): Anterior lobe of parietal callus wedgeshaped and covering posterior margin of umbilicus; umbilical callus subquadrate and attached to parietal callus with a shallow groove.
Typical adult form (phenotypes 3Ta-b:
PI. 17, Figs. Ma-c, PI. 18, Figs. Pa-Qc, PI. 19,

Figs. Aa-Mc): Anterior lobe of parietal callus
prominent but rarely indistinct; umbilical callus
semicircular to tongue-like, separated fromparietal callUS by a narrowly to broadly roundedsulcus; transverse groove on umbilical callus weak
to indistinct, situated posteriorly.
Unusual adult form (phenotypes 3Ua-b: PI.
17, Figs. Ha-Kc): Shape of callosity is nearly
identical with that of juvenile form but umbilicalcallus relatively larger and more swollen.
Description. -Shell relatively large (phenotype
3Tb) or relatively small (phenotype 3Ta) in size,
moderate in thickness, globose to globose elongate in form; body whorl greatly inflated withslightly concave to flattened shoulder; nuclear
whorls 2-1/2, smooth, separated from the firstconch whorl with a weak groove; postnuclear
whorls 2-1/2 in holotype; suture moderately
impressed. Spiral sculpture of microscopic,
closely spaced, minutely wavy costellae, andof subsutural, very weakly developed ridge inearly conch whorls (phenotypes 3Ja, 3Ta and3Ua) or subsutural, minutely incised band

Explanation of Plate 17
Figs. Aa-Bb. Phenotype JJ of Glossaulax hyugensis (Shuto): Aa-b, IGUT no. 15699-2, Loc.
M-1, x2.2; Ba-b, !GUT no. 15694-1, Loc T-2, x2.2.
Figs. Ca-b.
Phenotype 3Ja of Glossaulax hagenoshitensis (Shuto): IGUT no. 15700-1, Loc.
M-1, x2.I.
Figs. Da-Fb. Phenotype 3Jb of Glossaulax hagenoshitensis (Shuto): Da-b, IGUT no. 15705-1,
Loc. K-10, x2.8; Ea-b, !GUT no. 15705-4, Loc. K-10, x2.5; Fa-b, IGUT no. 15717-1, Loc.
K-3, x2.3.
The small letters of a and b of A-F indicate, respectively, front and basal views of specimen.
Figs. Ga-c.
Intermediate form between phenotypes 3Ta and 3Ua of Glossaulax hagenoshitensis(Shuto): holotype, GK. L8003, Loc. M-1, x2.0.
Figs. Ha-Ic. Phenotype 3Ua of Glossaulax hagenoshitensis (Shuto): Ha-c, IGUT no. 15702-10,
Loc. M-2, xI.3; Ia-c, IGUT no. 15712-3, Loc. K-12, xI.9.
Figs. Ja-Kc. Phenotype 3 Ub of Glossaulax hagenoshitensis (Shuto): Ja-c, IGUT no. 15703-26,
Loc. K-1, xI.6; Ka-c, IGUT no. 15705-48, Loc. K-10, x1A.
The small letters a, band c of G-K indicate, respectively, apical, front and basal views ofspecimen.
Figs. La-c.
Neverita incei (Philippi): IGUT no. 15719-5, Stradbroke Island, Queensland,
Australia (Recent), xI.2.
Figs. Ma-c.
Phenotype 3Ta of Glossaulax hagenoshitensis (Shuto): GIYU no. 568-3, Loc. M-1,
xLI.
The small letters, a, band c of L-M indicate, respectively, apical, front and basal views ofspecimen.
Figs. Na-b.
Polinices sagamiensis Pilsbry:' IGUT no. 15721-4, Loc. K-1, xO.6.
Figs.Oa-b.
Glossaulax reiniana (Dunker): IGUT no. 15722-13, Loc. 0-1, xLI.
The small letters a and b of N-O indicate, respectively, front and basal views of specimen.

MAJIMA: Variation ot G lossau lax (Gastropoda)

Plate 17

Fb

o,I
I

Ga

, "/

Ha

la

Ja

Ka

Ob

797.

Variation of Glossaulax (Gastropoda)(phenotypes 3Jb, 3Tb and 3Ub), both of whichstart from the second conch whorl; axial sculpture of incremental, prosoclinal growth linesthat are most distinct at base and below suture.
Parietal callus moderately to strongly developed,
moderately filling posterior apertural angle;
anterior lobe strong but rarely indistinct. Umbilicus broadly (phenotypes 3Ja-b and 3 Ta-b )to narrowly (phenotypes 3Ua-b) open, hornlike to U-shaped in form, deeply excavating
anterior inner lip of aperture; sulcus indistinct(phenotypes 3Ja-b and 3Ua-b) or distinct(phenotypes 3Ta-b); umbilical callus moderate(phenotypes 3Ja-b and 3Ta-b) to large (phenotypes 3Ua-b) in size, subquadrate (phenotypes
3Ja-b and 3Ua-b) or semicircular to tonguelike (phenotypes 3Ta-b) in form, all forms withstrong funicle. Umbilical wall weakly sculptured
with incremental growth lines and reliable number of spiral striae, may be with a weak to distinct
ridge at its outer margin (phenotypes 3Jb, 3Tb
and 3Ub), and sharply separated from the baseby an acute angulation. Posterior inner marginof aperture distinctly to moderately angulate;anterior inner lip and outer lip thin except for
gradually thickening anteriorly; basal lip weakly(phenotypes 3Ja, 3Ta and 3Ua) or strongly(phenotypes 3Jb, 3Tb and 3Ub) thickened.
Remarks. -The measurements of the largest
specimen of G. hagenoshitensis from each
locality are given in Table 4. A specimen illustrated by Martin (1905) as Natica ampla Philippi
from the middle Pliocene Sonde bed of Java,
Indonesia (pI. 39, fig. 628 in Martin, 1905)
seems to be identical to the phenotype 3Ta or
3Tb of G. hagenoshitensis. Unfortunately it isdifficult to be certain of this, based on Martin's
single illustration.
Neverita incei (Philippi), a common Australianshallow water species (Cernohorsky, 1972, p.
100, pI. 26, fig. 6; Wilson and Gillett, 1980, p.
38, pI. 18, figs. 4-4b) illustrated in PI. 17, Figs.
La-c, very closely resembles the phenotype 3Tbof G. hagenoshitensis in having a subsutural,
weakly incised band, spiral angulation dividing
the base and the umbilical wall, and a distinct
ridge along the outer margin of an almost flat

133umbilical wall, but it differs slightly from thephenotype 3Tb by being small in size (up to 30
mm in length (Cernohorsky, 1972)), and by having a relatively large umbilical callus sculptured
with many weak wrinkles. N. incei shows dimorphic variation in its coloration. One coloredform is represented by flesh-tone whorls, withwhite base and white umbilical callUS. The othercolored form has dark purple whorls, brown baseand brown umbilical wall; brown base is separated
from purple whorls by a narrow white spiralband; umbilical callus is white with light brownmargin (PI. 17, Figs. La-c). Though the coloration of many specimens of G. hagenoshitensis has
been lost, a few specimens from the Takanabe
Member of the Koyu Formation at Loc. M-1
preserve color (PI. 17, Figs. Ma-c): namely, thewhorls are dark gray but become gradually paler
toward the aperture and suture; base and umbilical wall are dark brown, and separated fromthe dark gray whorls by a light yellowish spiralband; callus is white. The color pattern of thesecond colored form of N. incei (PI. 17, Figs.
La-c) and that of the specimen of G. hagenoshitensis from the Takanabe Member (PI. 17,
Figs. Ma-c) , therefore, closely resemble eachother. N. incei seems to be a descendant of G.
hagenoshitensis but the former species is alsosimilar to Neverita joseph ina (Risso), the typespecies of Neverita, which ranges in age from
Oligocene to Recent in Europe (SvagrovskY,
1982). To confirm the phylogenetic relation between G. hagenoshitensis and N. incei, further
investigation is necessary.
Glossaulax hagenoshitensis has been taxonomically confused with Polin ices sagamiensis
Pilsbry in the Kakegawa Fauna and with Glossaulax reiniana (Dunker) in the Omma-Manganzi
Fauna. A specimen iliustrated by Shuto (1964)
as Polin ices (Neverita) sagamiensis from theKoyu Formation (pI. 42, fig. 2 in Shuto, 1964:
PI. 19, Figs. Ga-c) is identified with the phenotype 3Tb of G. hagenoshitensis. Phenotype 3Tb
has been also confused with P. sagamiensis by
Itoigawa and Shibata in Morishita (1977) inthe Dainichi Member of the Lower Kakegawa
Formation (pI. 30, fig. 18 in Itoigawa and134

Ryuichi MAJIMA

Shibata in Morishita, 1977). P. sagamiensis
occurs from the Dainichi Member of the Lower
Kakegawa Formation (PI. 17, Figs. Na-b) and theAnanai Formation, but only in small numbers.
P. sagamiensis is distinguished from G. hagenoshitensis by having a rounded base, smoothumbilical callus and a shallow groove aroundthe funicle (PI. 17, Figs. Na-b). A specimen illustrated by Kaseno and Matsuura (1965) as
Neverita (Glossaulax) reiniana from the Omma
Formation (pI. 2, figs. 32, 33) is identified withphenotype 3Tb of G. hagenoshitensis. Though G.
reiniana occurs in the Omma Formation (PI. 17,
Figs. Oa-b) in association with G. hagenoshitensis
at Loc. 0-1, it is distinguished from the latter
species by having a small umbilical callus and astrong groove around the funicle.
Among the specimens of G. hagenoshitensis,
a few specimens (PI. 19, Figs. Ba-c, Ia-c) havebeen shallowly (PI. 19, Figs. Ba-c)) or deeply(PI. 19, Figs. Ia-c) bored in the anterior end ofumbilical callus. When Wrigley (1949) described
the English Eocene and Oligocene Naticidae, hementioned:"In several of the species described in thispaper a few specimens have been bored by aparasite or commensal. The boring is always
in the same place, . . . . " at the rear of the

middle plug. This parasite, or whatever it was,knew exactly where to find the thickest partof the shell, and in a place which was conveniently adjacent to excreta. These borings arenever bevelled like the usual perforations inmolluscan shells . . . .. Until their true nature
is noticed they falsify the appearance of theplug and columellar border."The borings of the specimens (PI. 19, Figs.
Ba-c, Ia-c) are considered to be due to aparasite or commensal.

Concluding remarks
The intraspecific variation in the three Glossaulax species, G. hyugensis (Shuto), G. nodai,n. sp., and G. hagenoshitensis (Shuto) was
studied on the basis of more than 600 individuals
collected from 24 localities. G. hyugensis andG. hagenoshitensis show "dimorphic" variations
at the adult stages and their juveniles differ, tovarying degrees, from the adults. G. nodai,
however, has an uniform shell morphologies
throughout growth. The mode of the ontogenetic
variations of the three species is explained bya model of heterochronic evolution in which an
imaginary ancestral species is presumed.
The three important results of the present

Explanation of Plate 18
Figs. Aa-Eb. Phenotype 1T of Glossaulax hyugensis (Shuto): Aa-b, holotype, GK. LB009, Loc.
M-l, xL3; Ba-b, IGUT no. 15701-23, Loc. M-2, xL2; Ca-b, IGUT no. 15691-7, Loc. T-l,
xL4; Da-b, IGUT no. 15693-7, Loc. T-2, xL2; Ea-b, IGUT no. 15716-1, Loc. K-9, xLI.
Figs. Fa-Jb. Phenotype 1U of Glossaulax hyugensis (Shuto): Fa-b, IGUT no. 15699-44, Loc.
M-l, xLI; Ga-b, IGUT no. 15701-19, Loc. M-2, xL2; Ha-b, IGUT no. 15691-6, Loc. T-l,
xL5;Ia-b, IGUT no. 15693-4, Loc. T-2, xO.9; Ja-b, IGUT no. 15716-3, Loc. K-9, xO.B.
Figs. Ka-b. Intermediate form between phenotypes 1T and 1 U of Glossaulax hyugensis(Shuto): IGUT no. 15699-40, Loc. M-1, xO.B.
Figs. La-Db. Phenotype 2T of Glossaulax nodai, n. sp.: La-b, holotype, IGUT no. 15695, Loc.
K-13, x6.6; Ma-b, paratype, IGUT no. 1569B, Loc. M-5, xO.9; Na-b, paratype, IGUT no.
15697-6, Loc. K-17, xO.9; Da-b, paratype, GIYU no. 563, Loc. N-l, xLO.
Figs. Pa-b.
Phenotype 3Ta of Glossaulax hagenoshitensis (Shuto): IGUT no. 15692, Loc. T-3,
xL4.
The small letters a and b of A-P indicate, respectively, front and basal views of specimen.
Figs. Qa-c.
Phenotype 3Tb of Glossaulax hagenoshitensis (Shuto): IGUT no. 15706-39, Loc.
K-17, xL1.
The small letters a, band c of Q indicate, respectively, apical, front and basal views ofspecimen.

MAJIMA: Variation of Glossaulax (Gastropoda)

Plate 18

Cb

Qa

797.

Variation of Glossaulax (Gastropoda)

study are briefly summarized as follows:
1. The apparent dimorphic variations ofboth G. hyugensis and G. hagenoshitensis areinterpreted as different growth stages on thebasis of the model of heterochronic evolution(Text-fig. 10). The two adult forms of both
species indicate continuous variation but notdiscontinuous one. There is no essential difference among the individuals of each species
except for the continuously different timing of
the onset of development toward the next
growth stage (phenotypes 1 U and 3Ta-b).
2. The three species are best characterized
by the range of morphological variation including the difference of the frequency of the adultphenotypes of each species. In the morphologicalvariation of the three species (Text-fig. 9), thetypologically similar forms are classified into
different species (phenotypes 1J and 2T; IT
and 3Ja-b; IT and 3Ua-b; lU and 3Ta-b)
and the typologically different forms into thesame species (phenotypes 1T and 1 U; 1J andlU; 3Ta-b and 3Ua-b; 3Ja-b and 3Ta-b).
The ranges of the morphological variations of
the three Glossaulax species are confronted withthe typological methodology.
3. The three species are one of the mostdominant and characteristic molluscan speciesof the Kakegawa Fauna and some of them havebeen misidentified with other naticid species.
Acknowledgments
The author wishes to thank Professor Hiroshi
Noda (University of Tsukuba), Dr. Louie
Marincovich, Jr. (U.S. Geological Survey, Menlo
Park, California), Dr. Kenneth J. McNamara(Western Australian Museum), and Dr. Norman
F. Sohl (U.S. Geological Survery, Washington,
D.C.), who kindly read the manuscript andprovided invaluable comments. Thanks are due
to Professors Hisayoshi Igo, Naoaki Aoki, and
Dr. Fujio Masuda (all of University of Tsukuba)
for reading the manuscript and giving valuableadvice. This paper has greatly benefited fromthe criticisms by the scientists mentioned above.
Remnant errors of logic and expression are

135

entirely mine.
I am indebted to Dr. Nelly Hooper Ludbrook(Australia) for giving valuable information of
Neverita incei, and to Professor Tsugio Shuto(Kyushu University), and Professor Yoshikazu
Hasegawa and Mr. Kimihiko Ozaki (both of
Yokohama National University) for their permission to observe the specimens preserved in their
universities. I am also grateful to Dr. Kazutaka
Amano (Joetsu University of Education), Dr.
Makoto Ito (University of Tsukuba), Mr. Hirokazu Takahashi (University of Tsukuba SeniorHigh School at Komaba) and Mr. Tomonori
Shibata (Arabian Oil Company) for their different kinds of help and suggestion giving during
the course of this study.
Finally I wish to thank an anonymous referee
for reading the manuscript and offering suggestions for its improvement.
References
Alberch, P., Gould, S. J., Oster, G.F.and Wake,
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and phylogeny. Paleobiology, vol. 5, no. 3,
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Cernohorsky, W. O. (1972): Marine shells of the
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Kaseno, Y. and Matsuura, N. (1965): Pliocene
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Katto, J., Nakamura, J. and Takayanagi, Y.
(1953): Stratigraphical and paleontological

136

Ryuichi MAJIMA

studies of the Tonohama Group, Kochi
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Makiyama, J. (1925): The evolution of Umbonium. Japan. Jour. Geol. Geogr., vol. 3, nos.
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Marincovich, L., Jr. (1977): Cenozoic Naticidae(Mollusca: Gastropoda) of the Northeastern
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Martin, K. (1905): Die Fossilien von Java.
Sam mI. Geol. Reichsmus. Leiden, Mollusken,
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McNamara, K. J_ (1982): Heterochrony andphylogenetic trends. Paleobiology, vol. 8,
no. 2, p. 130-142.
--(in press): A guide to the nomenclature ofheterochrony. Jour. Paleont.
Noda, H_ (1965): Some fossil Anadara fromsouthwest Japan. Trans. Proc. Palaeont. Soc.
Japan, N_S., no. 59, p. 92-109, pis. 10-11.
Odhner, N. H. (1913): Northern and Arctic
invertebrates in the collection of the Swedish
State Museum. VI. Prosobranchia. 2. K.
Svenska Vetenskapsakad., Handl., vol. 50,
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Explanation of Plate 19
Figs. Aa-Fc. Phenotype 3Ta of Glossaulax hagenoshitensis (Shuto): Aa-c, IGUT no. 15700-45,
Loc. M-1, xO.9; Ba-c, IGUT no. 15702-13, Loc. M-2, x1.2;Ca-c, IGUTno.15690-1, Loc.
T-1, x1.0; Da-c, IGUT no. 15712-8, Loc. K-12, xO.8; Ea-c, IGUT no. 15715-2, Loc. K-9,
xO.8; Fa-c, IGUT no. 15714-14, Loc. K-8, xO.8.
Figs. Ga-Mc. Phenotype 3Tb of Glossaulax hagenoshitensis (Shuto): Ga-c, GK. L7987, Loc.
M-4, xO.9; Ha-c, IGUT no. 15705-108, Loc. K-10, xO.8; Ia-c, IGUT no. 15717-15, Loc.
K-3, xO.9; Ja-c, IGUT no. 15688-1, Loc. 0-1, xO.8; Ka-c, IGUT no. 15689, Loc. 0-3,
x1.5; La-c, IGUT no. 15703-109, K-1, xO.8; Mb-c, GIYU no. 567-3, Loc. N-1, xO.9.
The small letters a, band c of A-M indicate, respectively, apical, front and basal views ofspecimen.

Plate 19

MAJIMA: Variation ot Glossaulax (Gastropoda)

Ha

la

Ga

Ib

Gb

Ie

Ke

La

797.

Variation of Glossaulax (Gastropoda)

Japan, and its evolution (Part 2). Jour.
Geol. Soc. Japan, vol. 42, no. 503, p. 449482 (in Japanese).
Suzuki, K. (1934): A few evidence on the evolu·tion of Umbonium. Jour. Geol. Soc. Japan,
vol. 41, no. 485, p. 67-81 (in Japanese).
Svagrovsky, J. (1982): Archaeogastropoda und
Mesogastropoda des oberen Badenien vonBorsky Mikulas (No-Teil des Wiener Beckens)und ihre stratigraphische Bedeutung. Geol.
Carapath., vol. 33, no. 1, p. 3-50, pis. 1-10.
Tsuchi, R. ed. (1979): Fundamental data on

Japanese Neogene bio- and chronostratigraphy. Shizuoka University, Shizuoka,
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Neogenebio· and chronostratigraphy.
-Supplement- Shizuoka University, Shizuoka, 126 p.
Wilson, B. R. and Gillett, K. (1980): Australianshells. A. H. & W. Reed PTY Ltd., Sydney,
153 p., 58 pis.
Wrigley, A. (1949): English Eocene and Oligocene Naticidae. Proc. Malac. Soc. London,
vol. 28, no. 1, p. 10-30.

----------------

Aki 'ii:"¥;,
Ananai Jl:P-],
Asuka :lIH';,
Dainichi :;J( B,
Hagenoshita '1C0)""f,
Hanemachi :j:jm.IIIJ,
Haranoya 1JRfi-,
Higashidani !j~{r,Hongo·Higashi :;$:lJ!I;}U,
Honohashi
1JO)iiifj,
Kami-lida J:bfiill,
Koonji :l\';-;;r.'#,Koyu ~'C.ifi,
Nahari ~+flJ,
Nihonmatsu
Shintomi=*11,
Oku !$!"
Okuwa (Omma) ~J:::z,Sai Nc,Shimo-Saigo riffijjl)5,
machi ~~IHJ,
Suchi f;'iJ~,
Takanabe-machi il1ii:mlIHJ,
Tate-machi ffglllJ,
Tonohama H!f
I iJ~,
Tonoya''ifi,
Torihama jjjji~,Yasuda-mac hi 1CrufllJ

iffiJ.ij B *I&JtJ]'lfr1: R~ ffO) Clossalliax ('/ ~ !J -}j 1 kit) CIili,@lf.LJ: !J"7 -}f 1 H) 0) 3 MlO)
B *0) I&Jtlj~1:R 0) iliil=t:. Clossalliax 0) 31i1i:, Clossalliax hyugensis(Shuto), C. nodai, n. sp. :to J: <.Y C. itagenoshitensis (Shuto) O)fifl'lm:J',';J:24@l'tt!17J'I?f*
4* U:.¥:J 600 OOf*O)~*~~..., -OJf9'l: U:' o ;: 0) 31i1i:(;):, !W,if=i¥JI=-, ~ t:.J1QJ;f,Ei~f=-n\.;fpI.J;m:t.l:I), -t L"C ft!1.0) Clossalliax O)fl1U:: f~tdi'lHL~:to HHaIfU:I!~Hl~~5H-t Q.p;.:jkt.J:%JI':' J: ...,"C IKlJiJ ~ Q 0"=~i¥J" t.l:m:~I.J;, C. hyugensis
C. hagenoshitensis O)JiJt,l'tO)i1'I~0))fj~~=-~:Z2lb1?
nQ o C. hyugensis O)JiJt,l'to) -1J0)l!£~~{;l:. C. hagenoshitensis O)JiJt,l'tO)-1JO)~J',~I=­
w."C:to IJ, it:. C. hyugensis O)JiJt,l'to) t ') -1JO)l!£J',~fi C. hagenoshitensis O)/R,l'to) t') -1J0)l!£J',~~=- W. Q 0 -t n~=- t 1.J·I.J,h I? of, ;: 0) 2 fjO)mw. U:. m:J',~ 0) Jijlj]tfi, mliffij~=-J',
t.l:",,"C\,'Qo C. nodai U:, LI.J'L, JiJtffi:';J:iiflC"C-~O)i*~O))fj!L~~~-to iit!wO))fj!L~I':'1'*l
L "C, C. hYllgensis O)j;I],l'tfi C. nodai 1=-f.!;!."C:to IJ, ~ t:. C. hagenoshitensis O)::\j],l'tli,
C. hYllgensis O)JiJt,l'to) "=~e~" td£J',O)-1JO)~J',~f=-W.Qo ~ I?~=-, C. hagenoshitensis
Ii, tiiil"""f cJljfR~O)mJ.iZ2O),Ii\I;~U-(", 2 ":)O)J',FJfeJt.l:IJrJ',~'=-Bvt Q;: c i.lq±:*Qo ;: 0) 3fj
0) Je1:J: 0) 1JrJ', 0) f*;i:l:;li, ~(f5!J:O)mJ'efiT!~f.&:~Lt:. heterochrony O)-t:TJt.- v=-J:...,"C ~fjJ3

flfifl'l~~:

n

~nQo

137

*;Z.

c

c

C. hagenoshitensis Ii, Polin ices sagamiensis Pilsbry
Clossaulax reiniana(Dunker) v=-7H!l:~J:~f'ij~ n ·(\"t:.I.J;, H~FlllillO)M~I=-~-:)\""'C, ;:;tel? 2fji.l>l:' fjJ3ogH=-1K
~~nQo
~&~-

Trans. Proc. Palaeont. Soc. Japan, N.S., No. 138, pp. 138-147, pIs. 20, 21, JUly 15, 1985

798. ONTOGENIES OF TWO MIDDLE CAMBRIAN CORYNEXOCHIDTRILOBITES FROM THE CANADIAN ROCKY MOUNTAINS*CHUNG-HUNG HU
Department of Earth Science, Taiwan Normal University, Taipei

Abstract.

The present report describes the ontogenetic developments ofFieldaspis quadriangularis, n. sp. and Albertella limbata Rasetti from the Middle

Cambrian, Alberta, Canada. The morphogenic characteristics of these two species
during their different ontogenetic stages are similar to those of Bathyuriscus
fimbriatus Robison and Ptarmigania aurita Resser from the North American continent. The similar ontogenetic characteristics make them a natural taxonomic groupand possibly descendants from a common ancestor.

Introduction

paraprotaspid shield shows the presence of a
protopygidium and a well-segmented axial lobe;
the early meraspid cranidium has a broad cylindrical glabella expanded both anteriorly andposteriorly, and the presence of a narrow anterior border; the late meraspid cranidium has
an expanded anterior glabella, broad anteriorborder, and broad anterior fixigenal area.
The ontogenetic characteristics of Fieldaspis quadriangularis and Albertella limbata areclosely similar to those of Bathyuriscus
fimbriatus Robison (1967) and Ptarmigania
aurita Resser (Hu, 1971) as reported from theMiddle Cambrian of North America. The protaspis of all these species possesses rather narrowanterior second and third axial segments, aforwardly expanded frontal lobe, a large palpebral lobe; the meraspid cranidia are trapezoidal
in outline; the cylindrical glabella is expandedboth anteriorly and posteriorly, and protrudes
anteriorly; the palpebral lobe is rather large.
Evidently that these four species of trilobites
are a natural taxonomic group and with a close
phylogenetic relationship.
The ontogenetic developments of the present
trilobites are differentiated from that of the

The purpose of the present report is to illustrate the ontogenetic developments of Fieldasp is quadriangularis, n. sp. and Albertellalimbata Rasetti. The studied materials werecollected from the Mount Weed section, Banff
National Park, Alberta, Canada. They comefrom the Mount Whyte and Cathedral formations (the Plagiura-Poliella and Albertella zones)of the Middle Cambrian. The collections weremade during the Second International Symposium on the Cambrian System, Field-trip 2
to Canadian Rocky Mountains, Alberta andBritish Columbia in 1981. The morphogenic
characteristics of these two trilobites are similarand can be subdivided into five metamorphic
stages, i.e., anaprotaspid, metaprotaspid, paraprotaspid, early meraspid, and late meraspid.
These are briefly defined as follows.
In the anaprotaspid stage, the shield is withor without an axial lobe but with a longitudinal
median furrow, a large frontal lobe, and a small
terminal portion; the metaprotaspid has a cylindrical axis, with or without axial segments; the*Received June 10, 1984.
138

798. Ontogeny of Trilobites

ptychoparioids: Crassifimbra walcotti (Resser)(Palmer, 1958), Glyphaspis cf. parkensis Rasetti(Hu, 1971), Ehmaniella burgessensis Rasetti(Hu, 1984), Sao hirsuta Barrande (Whittington,1959), Trymatospis convex us Hu and Yuknessaspis santaquinensis Hu (Hu, 1972) from theMiddle Cambrian in having protaspis with arather weakly developed axis and the absenceof the second to third axial segments; themeraspid cranidium has a large palpebral lobe
and a somewhat forwardly expanded glabella.
These different morphologic features of the twogroups of trilobites clearly show that they are
phylogenetically unrelated and had independent
ancestral stocks.
The author wishes to express his thanks to
Dr. J. D. Aitken, Geological Survey of Canada,Calgary, Alberta for guidance of the field trip
and personal help. Thanks go to Dr. K. E.
Caster, University of Cincinnati, Ohio for readingover the present manuscript and corrected with
the English text. The figured specimens are allstored in the Geology Museum, Univesity ofCincinnati, Ohio (UCGM).
Systematic paleontology
Genus Fieldaspis Rasetti, 1951
Fieldaspis quadriangularis, n. sp.

PI. 20, Figs. 1-29, Text-figs. 1 A-N.
Diagnosis.-Cranidium quadrate in outline,
convex, with cylindrical glabella slightly expanded forwardly; four pairs of glabellar furrows
are seen; no preglabellar field is present, butthere is a narrow anterior border; fixigenae
narrow, flat, and occupied by a pair of large
palpebral rings; posterior fixigenae narrow andof about the same width as the occipital ring;
Iibregenae sickle-shape and elongate; hypostoma
acute, triangular and ankylosed with the rostrum;
pygidium semicircular and with a pair of longcaudal spines.
Description.-The quadrate cranidium has arather large cylindrical glabella which is moderately convex, and has no preglabellar field,
but there is a narrow anterior border elevated139

along the anterior glabellar margin; the glabella
is convex above the flattened fixigenae, .it isdemarked by a dorsal furrow and has four pairsof glabellar furrows; the anterior first pair offurrows are faint and protrude forwardly; thesecond pair are deeper than the first pair andextend horizontally; the third and fourth pairs
are deeper and more distinct than the anterior
two pairs; they are directed posterolaterally;
the anterior facial sutures are slightly divergent
and convex; the posterior facial suture runs
almost parallel to the narrow posterior fixigenal
border; the long palpebral ring is convex andwell delimited by a palpebral furrow; no occipitalspine or tubercle is !mown, but faint wrinkles
are present along the posterior margin.
The Iibregena is narrowly elongate and has amedium-sized genal spine; the narrow ocular
platform is convex, elevated from the lateral
marginal furrow to the large ocular ring; bothof the lateral and posterior marginal furrows
are well defined and connected at the genal
angle roundly.
The hypos tom a is triangular in outline andankylosed to a narrow rostrum; the medianbody is oval-elongate and convex, and has a Ushape posterior inner marginal border; the sidesof the median body are distinctly impressed bya pair of elongate pits, and flattened antero·lateral wings are present.
The pygidium is transverse and nearly sub.
quadrate with posteriorly arched marginalborder; the convex axis is divided into two
distinct axial rings and a large terminal portion
which is possibly made up of two or threerudimentary axial rings; the pleural lobe is gen t1yconvex, well demarked by a pair of intropleuralfurrows, and two to four pairs of faint grooves;a pair of long slender caudal spines extend
posterolaterally from the first to second pygidial
segments; the axial rings are each marked with a
median tubercle.
The skeletal surface is covered by faint tomedium coarse granules; both anterior glabella
and anterior median hypostomal margin are
impressed by a rounded pit; a few coarse granules occur along the anterior cranidial border,and faint ridges are parallel to the lateral border

140

Chung-Hung HUof the rostrum.
Remarks.-The studied materials were collected from the base of the Mount Weed Section
far below the Albertella limbata Rasetti andPlagiura cerops (Walcott) zones, and above theOlenellus Zone. The trilobite fragments areembedded in a dark grey, faintly crystalline
limestone. The present species is represented
by abundant adult and immature skeletons,
which show the very well preserved ontogenetic
sequence. This species is differen tiated fromF. furcata Rasetti, F. bilobata Rasetti, and F.
superba Rasetti (Rasetti, 1951) by its quadratecranidium, broader anterior fixigenae, and lessdivergent anterior facial suture; the pygidium
possesses a pair of large caudal spines, and thepygidial axis bears median tubercles; the posterior marginal border is well defined.
Locality and horizon. -Mount Weed Section,near Bow Lake, Banff National Park, Alberta;
Mount Whyte Formation, Plagiura-''Poliella''
Zone, Middle Cambrian.
Fieldaspis quadriangularis, n. sp., ontogeny
Anaprotaspid stage (PI. 20, Figs. 1-6 &Text-figs. lA, B). The shield is round with bothanterior and posterior margins curving inwardly,
and moderately convex; the measurement of
the shield is 0.26 to 0.38 mm in length (sag.);
the axial lobe is a longitudinal furrow, whichsuggests the gut position; no axial ring is observed but two to three pairs of pits are present
besides of the median furrow; the triangular
frontal lobe expands forwardly from themedian furrow and with a pair of lateral eyebrow ridges extending laterally; the fixigenal
area is broad and moderately convex; the shieldis possibly surrounded by a narrow flat marginalborder.
The morphogenesis of the ins tars during
present stage indicates that the earliest skeleton
has a longitudinal furrow along the axial region
but in the later anaprotaspids the shield axis
possesses a large frontal lobe, two to three pairsof axial knobs, and a small terminal portion.
Metaprotaspid stage (PI. 20, Figs. 7,8 & Text-

fig. 1C). The shield is round, moderately convex,
with the anterior margin straight, and the posterior margin curving inwardly; the measurementof the shield is 0.42 to 0.40 mm in sagittal
length; the axial lobe is possibly faintly definedby three central rings, a small terminal portion,
and a large frontal lobe; these central rings are
made from three pairs of central knobs fromthe previous stage; the convex rounded frontal
lobe is extended with a pair of eyebrow ridges
extending from the anterolateral sides andrunning a short distance to connect with thepalpebral ridge; a pair of distinct frontal pits
is marked at the sides of the frontal lobe where
the palpebral lobes are initiated; the narrowwell-defined palpebral lobe runs posterolaterally
from the frontal pits for a short distance andends before reaching the transverse mid-line of
the shield; the terminal portion is a small semicircular node that is elevated at the posterior
median margin; the surface of the shield iscovered by faint granules; the narrow flat marginal border surrounds the posterior half of theshield, and forms a pair of short spines at theposterolateral margin.
Paraprotaspid stage (PI. 20, Figs. 9, 10, 12,
13 & Text-figs. 1D, E). The shield is convex andround to trapezoidal in outline; the sagittal
length of the shield varies from 0.50-D.66 mm;
the axial lobe contains a large rounded frontal
lobe three transverse rings, and a small terminal
portion; these are all well-defined by dorsal
and ring furrows; the frontal lobe has a similar
structure to that of previous stage with a pairof eyebrow ridges and distinct pits; the posteriorshield margin is equal to or broader than theoccipital ring and bears a pair of saw-teeth
located at the lateral ends; the surface of theskeleton is covered by faint granules, and there
is a narrow flat margin along the posterior andlateral margins.
The distinct morphologic characteristics ofthe present stage are: the axial nodes are complete and the median furrow is absent; theposterior fixigenal border increases in widthfrom narrow to broad, which suggests thepresence of the protopygidium or the thoracic

798. Ontogeny of Trilobites

segments.
Early meraspid stage (PI. 20, Figs. 14-16& Text-fig. IF). The cranidium is trapezoidal
in outline, moderately convex, and the sagittal
length is 0.75 to 1.25 mm; the glabella is oblong,
gently expanded anteriorly from the second
glabellar furrow; the first glabellar segment or
the frontal lobe is a larger segment than thefollowing and protrudes into the frontal furrow;the second to fourth glabellar segments are
faintly dissected ring furrows, and the convex
subtriangular occipital ring bears a small mediantubercle; a narrow anterior border appears infront of the glabella and arches forwardly; thefrontal pits which were well marked in theprevious stage now becomes shallower; thepaired palpebral ring is parenthetic and extends
from the sides of the first glabellar segment to
end before reaching the posterior fixigenal
furrow; the posterior fixigenal border is about
as wide as the occipital ring; the surface isgranulate and a median impression is marked in
front of the anterior glabellar margin.
The morphogenesis of the present stage is:the anterior border appears; the glabellar furrows
are complete; both anterior and posterior facial
sutures increase in length.
Late meraspid stage (PI. 20, Figs. 17, 18 &Text-figs. 1 I, H). The cranidium is moderately
convex and measurement is about 1.50 to 2.50
mm in sagittal length; the glabella expands
forwardly from the posterior second glabellar
furrow with a rounded anterior margin; thefour pairs of glabellar furrows are complete
and the posterior parts of the first glabella are
deeply impressed and the following are shallow;
the occipital ring is subtriangular, convex, andbearing a minute median tubercle; the elevatedanterior border arches forwardly and is welldelimited by an anterior furrow; the narrowpalpebral lobe is well defined by the palpebral
furrow; it is elevated and situated posteriorly
to the transverse midline of the glabella; theanterior facial suture is short, slightly divergent,and convex; the posterior fixigenal area is triangular and the post-fixigenal border is about
the same width as that of the occipital ring;141

the fixigenal area is broad and flat between
the dorsal furrow and the palpebral lobe. The
cranidial surface is covered by faint granules
and a median impression is situated in front of
the anterior glabellar margin.
The present stage is differentiated fromprevious stage in having a broader anteriorborder, broader anterior fixigenal area, andposteriorly located palpebral lobe. A pair ofadditional glabellar furrows appears at the sidesof the anterior first glabellar segment.
The growth of the pygidium (PI. 20, Figs.
23, 24, 26, 28 & Text-figs. 1L, N). A small
pygidium measured about 0.3 mm in sagittal
length is made of three freely articulated segments and a small terminal plate; the axial lobe
is convex above the pleuron; the axial ring iswell separated by a ring furrow and bears adorsal spine on each axial ring. The pleural
bands each project into a pair of posteriorly
directed spines. Judging from the pygidial
structures this pygidium to the protaspid stage.
The next pygidium (PI. 20, Figs. 26, 28) in size
measured from 1.2 to 0.75 mm in sagittal length.
It is composed of three segments and a terminal
portion. If this pygidium is compared to theearlier stage, it is clear that the pygidial segments
are all ankylosed as a plate and show the adultstructure; however, their posterior marginalborder still remains incomplete, i.e., the marginal
saw-teeth are absent. Therefore, these specimens
are judged as representing meraspid pygidia.
Growth of the libregena (PI. 20, Figs. 11, 12).
The morphogenic characteristics of the libregena
during its different growth stage shows pro.
gressive reduction of the length of the genal
spine and an increase in the width of the ocular
platform.
Genus Albertella Walcott, 1908
Albertella limbata Rasetti, 1951

PI. 21, Figs. 1-32, Text·figs. 2 A-N.
Albertella limbata Rasetti, 1951, p. 154, pI.
18, figs. 8-17.
Remarks. -A small piece of dark grey, finely

Chung-Hung HU

142

8

A

E

o

F
H

K
J

•

L

M

•

," ,I
I

I

N

Text-fig. 1. Fieldaspis quadriangularis, n. sp.
A, B, two anaprotaspid shields, showing the median axial furrow and possibly coelomic nodes.
X 50; C, a metaprotaspis, showing the completion of the axial lobes and the axial segments. x42;
D, E, two paraprotaspid shields, showing the broadening of the posterior fixigenal border. x23,
x20; F, an early meraspid cranidium; notice the presence of the anterior border. x18; G, ameraspid libregena, showing the long slender genal spine and the lateral furrow extending into thegenal spine. x3.5; H, a late meraspid cranidium, showing the protruded anterior glabella and thebroadening of the anterior fixigenal area. x8; J, a holaspid cranidium. x3.7; I, K, immature andholaspid hypostomata, showing the association of the rostrum. x 9, x3; L, an early meraspid
pygidium. x31; H, an adult libregena. x3; N, an adult pygidium, showing the caudal spines andthe axial tubercles. x4.5.

798. Ontogeny of Trilobites

crystalline fossiliferous limestone was collectedfrom the same locality as Fieldaspis quadriangularis but stratigraphically slightly higher inthe Albertella Zone. The studied material contains rather abundant mature and immatureskeletons. They show ontogenetic preservation
very well. This trilobite is comparable to someoccurrences those reported by Rasetti (1951)
from the same general area.
Additional description. -The libregena is crescentic in outline, moderately convex, and has arather large ocular ring; both the anterior facial
suture and the posterior facial suture lines areshort; the ocular platform is narrow anteriorly
and broadens posteriorly; it is faintly marked byradial ridges; the lateral and the posterior marginal furrows meet at the genal angle, and run fora short distance into the genal spine. The hy·
postoma is acutely triangular in outline, convex,
and surrounded by a narrow marginal borderalong the posterior and lateral margins; theconvex median body is nearly triangular andsurrounded by a V-shape posterior furrow and apair of lateral elongate pits. The thoracic segment
is well impressed by a broad ring and intrapleuralfurrows; the axial ring and the pleural lobe are of
the same width; the pleural lobe terminates in aslender posterolaterally directed spine.
Locality and horizon. -Mount Weed Section,near Bow Lake, Banff National Park, Alberta;
Cathedral Formation, Albertella Zone, Middle
Cambrian.
Albertella limbata Rasetti, ontogeny
Anaprotaspid stage (PI. 21, Figs. 1, 2 & Textfigs. 2A, B). The shield is round, moderately
convex, and measures 0.26 mm in sagittal length;
the axial lobe is narrow and depressed as alongitudinal median furrow; the rounded frontal
lobe is convex with a pair of deeply demarked
pits situated anterolaterally; the paired eyebrow
shape ridges extend in front of the pits - thesides of the frontal lobe, and run posterolaterally
for a short distance; the posterior half of theaxial lobe is slenderly elevated into a small
terminal node at the shield margin. This suggests
the initial portion of the occipital ring. The

143

lateral lobe is rather broader than the axis,
convex, and surrounded by a narrow deflated
marginal border; the surface of the shield issmooth to faintly granUlate; there are possibly
two pairs of short marginal spines at the lateraland posterolateral shield margins.
Metaprotaspid stage (PI. 21, Figs. 3-6 & Textfig. 2C). The shield is round to quadrate in outline, convex; it measures about 0.25 to 0.35 mm
in length (sag.); the axial lobe is well developed
but axial rings are indistinguishable; the frontal
lobe is broad, larger than the following axia,
convex, and well marked by a pair of lateralpits; the paired eyebrow ridges extend fromthe anterolateral frontal lobe for a short distance;a pair of palpebral lobes is developed behindthe frontal pits and extend anterolaterally tothe transverse mid-line of the shield; the narrow
axial lobe is well-defined by furrows and theaxial ring is poorly developed; but a few pairsof pits are faintly marked along the axial furrow,
which suggests the presence of the axial segments; the terminal node is small, convex, andsituated at the posterior shield margin; thepleural lobe is twice as wide as the axis, convex,
and no marginal border is visible. The surfaceof the shield is rough or faintly granulate; certain
specimen shows faint cephalic segmental furrows
on the pleural region.
The ontogenetic characteristics of this stage
are: the axial lobe increases in broadness; unsegmented or segmented axial lobe tapering posteriorly or expanded at both anterior and posterior ends from the anterior second axial ring;
the axial furrows increase in depth from shallow
to well recognizable.
Paraprotaspid stage (PI. 21, Figs. 7-11 &Text-figs. 2D, E). The cranidium is quadrate totrapezoidal in outline, moderately convex;
the sagittal length varies 0.50 to 0.65 mm; theaxial lobe is deeply demarked anteriorly andexpands forwardly and posteriorly from thesecond axial ring; the first axial ring or thefrontal lobe is the largest, convex, with a pairof lateral pits lying behind the eyebrow ridges;
the narrow palpebral lobe is well defined by afurrow, and is elevated along the anterolateral
margin of the shield; the following axial rings

Chung-Hung HU

144

increase the size from the anterior second to
fourth, and there is a small terminal node representing the occipital ring; all of the axial
rings are well separated by transverse ringfurrows; the pleural lobe is about twice as wide
as the axis, convex, and has a very well developed
post-fixigenal border; the fixigenal margin issurrounded by a narrow flat border; the surfaceof the shield is covered by faint granules; a pairof large tubercle is marked at the sides of theposterior fourth axial ring-furrow.
The morphogenesis of the ins tars during thepresent stage is: the cranidium changes from
quadrate to trapezoidal in outline and theglabellar ring is well defined; the posterior
fixigenal border increases in width and theprotopygidium appears.
Early meraspid stage (Pl. 20, Figs. 12-14,
16 & Text-fig. 2F). The cranidium is trapezoidal
in outline, moderately convex, and is about 0.85
to 1.7 mm in length (sag.); the axial lobe is
deeply demarked by dorsal furrows and expands
forwardly from the occipital ring furrow witha large-sized frontal lobe; the axial rings are welldelimited by transverse ring furrows which areshallow across the central line and deeply incisedto the dorsal furrows; the subtriangular occipitalring is convex and bears a minute median tubercle; a narrow anterior border appears in frontof the glabella; the large narrow palpebral ringis parenthetical and extends from the sides ofthe frontal lobe posteriorly to the narrow postfixigenal area; the post-fixigenal border is deeply
defined by a border furrow and is less broadthan the occipital ring; the surface of the shield
is faintly granulate and a few coarse granules
are present; the anterior margin of the frontal
lobe is marked with a distinct median pit.
A nearly triangular pygidium composed of
5 to 6 freely articulated segments is assigned tothe present stage. The first segment is the largest
and with the pleural bands protruding posterolaterally; the following segments are small andhave their pleural ends projected posteriorly;
the axis is about the same width as the pleurallobe and well demarked by axial ring furrows;
the intrapleural furrow of each segment is deep
and broad, and is subparallel to the pleural
bands; the axial rings all possess a single but
slender median spine.
During the present stage the cranidium
appears as a narrow anterior border; the glabellachanges from tapering forward to expanded
forward; the posterior fixigena decrease in

Explanation of Plate 20
Fieldaspis quadriangularis, n. sp.
a growth series of anaprotaspid shields; notice the incomplete axial lobe. 1-4, x50;
5, x45, 6, x43.
7, 8, two metaprotaspid shields, showing the genesis of the axial lobe. x38, x42.
9, 10, 12, 13, several paraprotaspid shields, showing the lateral expansion of the posterior
fixigenal border and the possible presence of the protopygidium. x32, x23, x20, x22.
11, a broken libregena. x3. (paratype).
14-16, three early meraspid cranidia; note the presence of the anterior border and thecompletion of the glabellar furrows. 14,15, x18; 16, x13.
17, 18, two late meraspid cranidia, showing the forwardly protruded glabella, broad anterior
fixigenal area, and the posteriorly located palpebral lobe. x8, x7.
19,25, a meraspid hypostoma and an holaspid hypostoma. x9, x3. (paratypes).
20,21,27, lateral and dorsal views of two broken cranidia. 20,21, x3.7; 27, x4. (21,22,
holotype; 27, paratype).
22, a complete libregena beside a partly broken thoracic segment. x3.5.
23,24,26, three mature and immature pygidia. x4.5; x31; x10, (paratypes).
28, a paraprotaspid cranidium and a meraspid pygidium. x14. (paratype).
29, a small piece of limestone, showing the abundance of the immature skeletons. x13.

Figs. 1-29.
1~,HU: Ontogeny of Trilobites

Plate 20

798.

A

8

Ontogeny of Trilobites

c

145

o

E

L

Text·fig.2. Albertella limbata RasettiA, B, anaprotaspides, x57; C, metaprotaspid, x50; D, E, two paraprotaspides, x38, x29; F, earlymeraspid cranidium, x20; H, late meraspid cranidium, x15; G, a meraspid libregena, x16; I, K, twoholaspid cranidia, x9, x4; J, a late meraspid hypostoma associated with a part of rostrum, x15; L,early meraspid pygidium, x20;M, late meraspid pygidium, x15.

146

Chung-Hung HU

broadness; the palpebral lobe increases in size
and the posterior facial suture-line is divergentposterolaterally to laterally straight.
Late meraspid stage (Pi. 21, Figs. 17, 18,21& Text-fig, 2H). The cranidium is elongate subquadrate in outline, convex, and is about 1.80 to
2.80 mm in length (sag.); the glabella is deeply
impressed by dorsal furrrows, which expand
forwardly with a rounded anterior margin; theglabellar furrows are complete, except that theposterior is incomplete; the occipital ring is large,
subtriangular, convex, and bearing a mediantubercle; the anterior brim is narrow, concave,
and with the marginal border turned upward;
the parenthetical palpebral lobe is deeply demarked by a palpebral furrow; it runs posterolaterally from the anterior first glabellar furrow
to the base of the occipital furrow; the anteriorfacial suture is divergent-anterolaterally and theposterior one, while divergent, is straight andalmost to the posterior fixigenal border. The
surface is covered by faint granules and an
impression is present in front of the glabella.
A small tiangular hypostoma (Pi. 21, Fig. 15& Text-fig. 2J) is arbitrarily assigned to thepresent stage; it is ankylosed with an archedrostrum anteriorly; the oval median body isconvex and elevated from the marginal borderby a distinct furrow; the posterior median bodyis occupied by a pair of transverse knobs laterally; the U-shaped inner marginal border is broadand convex, and demarked by a broad borderfurrow; the outer marginal border is rather
narrow and elevated from the border furrow;the anterior hypostoma is impressed by a median
depression.
The rostrum is arched anteriorly with its
lateral end broader than the central portion,
convex, and chevron-shape; the surface is possibly marked by parallel ridges at its lateral ends.
The supposedly late meraspid pygidium (Pl.
21, Figs. 29-31 & Text-fig. 2M) has a quadrate
outline, convex, with the axial lobe taperingslightly posteriorly; the axial lobe is made of 6-7
convex axial rings and a terminal portion; these
are well separated by ring-furrows; each of theaxial rings is occupied by a slender median tubercle or a short spine directed vertically; the wellsegmented pleural lobe is equal to or slightly
broader than the axis and has a pair of large
caudal spines directed posteriorly; the surface iscovered by faint granules.

Explanation of Plate 21
Figs. 1-32. Albertella limbata Rasetti
1,2, two anaprotaspides, showing the narrow poorly developed axial lobe. x57.
3~, a few metaprotaspides, showing the presence of the axis. 3-5, x50; 6, x45.
7-11, several paraprotaspid cranidia, showing the well developed fixigenal border and thesuggestion of the presence of the protopygidium. 7, x38; 8, x34; 9, x37; 10, x36; 11,x29.
.
12-14, 16, four early meraspid caranidia, showing the presence of the anterior border andthe parenthetic palpebral lobes. 12, x21; 13, x20; 14, x16; 16, x12.
17, 18,21, three late meraspid cranidia, showing the completion of the glabellar furrows andthe lengthening of the glabella. 17, x13; 18, x15; 21, x10.
15, an immature hypostoma ankylosed with the rostrum. x15.
20, an adult hypostoma, showing the elongation of the median body. x4.5.
19,23, two imcomplete libregenae. x15; x5.
22, part of a thoracic segment. x6.
24, 27, two adult cranidia, showing the morphologic varieties of the fixigenal lobe and theglabella. x3.8; x9.3.
26, an early meraspid pygidium. x20.
29-31, three late meraspid pygidia. 29, x15; 30, x8.6; 31, x7.7.
25,28,32, three holaspid pygidia. x9.5; x5; x5.

HU: On toge ny of Trilobites

Plate 2 1

2

7

3

8

13

12

28

29

14

15

30

31

16

32

798. Ontogeny of Trilobites
The morphogenesis of the present stage is:the glabellar furrows are nearly complete; thepalpebral ring increases in size; the post-fixigenal
area becomes narrower; the anterior facial
suture is divergently convex, and the posterior
one is divergently parallel to the fixigenal border.
The pleural lobe of the pygidium decreases inwidth and becomes equal in width to that of
the axis.
References
Aitken, J. D. (1981): The Cambrian System inthe southern Canadian Rocky Mountains,
Alberta and British Columbia (Second
International Symposium on the Cambrian
System). Guide book for field trip 2. 61 p.
(USGS. Colorado).
Hu, CoHo (1971): Ontogeny and sexual dimorphism of lower Paleozoic Trilobita. Palaeontographica Americana, vol. 7, no. 44, p.
31-155.
- - (1972): Ontogenies of two Middle Cambrian.
trilobites from Wasatch Mountains, Utah.

147

Acta Geol. Taiwanica, no. 15, p. 41-50(Taiwan).
- - (1984): Ontogenesis of Ehmaniella burgensensis Rasetti (Trilobita) from the Burgess
Shale, Middle Cambrian, Yoho Park, British
Columbia. Palaeont. Soc. Japan, Proc.
Trans., N.S., 135, p. 395-400, pI. 76.
Palmer, A. R. (1958): Morphology and ontogenyof a lower Cambrian ptychoparioid trilobite
from Nevada. Jour. Paleont., vol. 32, p.
154-170, pis. 25, 26.
Rasetti, F. (1951): Middle Cambrian stratigraphy and faunas of th Canadian Rocky
Mountains. Smith. Mis. Coil., vol. 116, no.
5,277 p.
Robison, R. A. (1967): Ontogeny of Bathyuriscus fimbriatus and its bearing on affinities of corynexochid trilobites. Jour.
Paleont., vol. 41, no. 1, p. 213-221, pI.
24, text-figs. 1-5.
Whittington, H. B. (1959): Ontogeny of Trilobita: Treatise on invertebrate paleontology,
Arthropoda 1, Pt. 0, Geol. Soc. America&
Univ. Kansas Press, p. 127-145(Lawrence ).

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Transactions and Proceedings of the PalaeontologicalSociety of Japan
New Series No. 138

July 15,1985

CONTENTS
TRANSACTIONS
795. LING, Hsin Vi: Early Paleogene silicoflagellates and ebridians from the Arctic
Ocean. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 79796. KANEKO, Atsushi: A Middle Devonian trilobite fauna from the Kitakami Mountains,
northeast Japan-II. The Calymenidae . . . . . . . . . . . . . . . . . . . . . . . . . . .. 94
797. MAJIMA, Ryuichi: Intraspecific variation in three species of Glossaulax (Gastropoda:
Naticidae) from the Late Cenozoic strata in central and southwest Japan .... 111
798. Hu, Chung-Hung: Ontogenies of two Middle Cambrian corynexochid trilobitesfrom the Canadian Rocky Mountains . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138