The Mesozoic Pelecypods 

Otapiria Marwick and 

Lupherella Irnla y, New 

Genus, in the United States 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 573-B 

The Mesozoic Pelecypods 

Otapiria Marwick and 

Lupherella Imlay, New 

Genus, in the United States 

By RALPH W. IMLAY 

CONTRIBUTIONS TO PALEONTOLOGY 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 573-B 

Presents the first records of 

Otapiria and Lupherella in the United States 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1967 
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEWART L. UDALL, Secretary 

GEOLOGICAL SURVEY 

William T. Pecora, Director 

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D.C. 20402 - Price 25 cents (paper cover) 
CONTENTS 

Page 

Abstract___________________________________________ B1 Biological relationships _____________________________ _ 

Introduction_______________________________________ 1 Comparisons of species _____________________________ _ 

Characteristics of Otapiria _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 1 Systematic descriptions _____________________________ _ 

Characteristics of Lupherella Imlay, n. gen _________ .. _ _ _ 2 Literature cited ____________________________________ _ 

ILLUSTRATIONS 

[Plates follow "Literature Cited"] 

PLA'l'E 1. Otapiria. 

2. Lupherella, n. gen., and Otapiria. 

Page 

B2 

3 

3 

10 

Page 

FIGURE 1. Index map showing occurrences of the pelecypod Otapiria in Alaska________________________________________ B7 

2. Index map showing occurrences of Lupherella boechiforrnis (Hyatt) in Oregon and California__ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 9 

TABLES 

Page 

TABLE 1. Distribution of Otapiria in space and time______________________________________________________________ B2 

2. Comparisons of Triassic and Jurassic species of Otapiria__________________________________________________ 4 

3. Comparisons of measurements of some Jurassic species of Otapiria and Lupherella _____________ - _- _- _--- _----- 5 

III 

237-493 0-67 

CONTRIBUTIONS TO PALEONTOLOGY 

THE MESOZOIC PELECYPODS OTAPIRIA MARWICK AND LUPHERELLA IMLAY, NEW GENUS 

IN THE UNITED STATES 

BY RA1JPH w. IMLAY 

ABSTRACT 

The pelecypod genera Otapirta Marwick and Lupherella 

Imlay, n. gen., both resembling the late Triassic genus Monotis, 

are recorded for the first 1time from Mesozoic bed•s in the United 

States. Lupllerella is represented by L. boechiformis (Hyatt) 

from beds of Pliensbachi·an age in eastern Oregon and California. It has not been found elsewhere. One species of 

Otapiri.a, named 0. tailleuri Imlay, n. sp., has been found in 

northern Alaska associated with or directly underlying Inoceramus cf. I. lucifer Eichwald, whose presence indicates an early 

Middle Jurassic or late IDarly Jurassic age not older than 

Toarcian. Another species, ·referred to as 0. sp. undet., has been 

found as float in the upper Yukon Valley in east-central Alaska. 

Its ·age is unknown, but the presence of the crinoid Pentacrinus 

subangularis var. alaska Springer in the same float indicates 

that beds of Early Jurassic age are present in the area. Otapiria. 

has been found previously in Upper Triassic to Upper Jurasrsic 

beds in New Zealand, Lower .Jurassic beds in New Caledonia, 

and Upper Tria,ssic to Lower Jurassic beds in northea·stern 

Siberia. 

INTRODUCTION 

The recent discovery of a monaticllike pelecypod in 

northern Alaska prompted the preparation of this 

paper. This pelecypod was found in a thin unit of organic shale directly overlying Upper Triassic beds and 

directly underlying, at least loca.lly, Lower Cretaceous 

beds containing Buchia of Valanginian age. It showed 

considerable resemblance to the genotype species of Otapiria Marwick (1935, p. 303; 1953, p. 95) from basal 

Jurassic beds in New Zealand (Trechmann, 1923, p. 270, 

pl. 15, figs. 6-9; Marwick, 1953, p. 95, pl. 11, figs. 7, 8) 

and to a species of 0 tapiria. from basal Jurassic beds 

in northeastern Siberia (Zakharov, 1962, p. 25-29, pl. 1, 

figs.1-16, pl. 2). Further study showed tha:t the gene·rie 

assignment to Otapiria was correct and that the genus 

has a fairly wide distribution in Upper Triassic and 

Jurassic beds of the Indo-Pacific and Arctic regions. 

The paper also includes a description of a new genus 

of another monotidlike pelecypod from beds of late 

Early Jurassic (Pliensbachian) age in Oregon and 

California. This pelecypod, herein named Lupherella 

n. gen., greatly resembles Otapiria and appears to be 

close~ly related to that genus. Attempts over many years 

to determine rt.he generic and fa.1nily relationships of 

L1.tpherella nra.de the writer fam.iliar with the characteristics of Otapiria and led to the identification of 

0 tapiria soon after its discovery in Alaska. 

Many thanks are due to Mr. J. A. Jeletsky of the 

Geological Survey of Oanada for his aid in locating 

pertinent Russian publications. Mr. I·an Speden of the 

New Zeal1and Geological Survey kindly furnished 

rubber imprints and descriptive data of Otapiria rnwrshalli (Trechmann), the type species of Otapiria. 

CHARACTERISTICS OF OTAPIRIA 

The genus Otapiria was defined by Marwick in 1935 

(p. 302), and Pseudmnonotis 11wrsha.lli (Trechmann) 

(1923, p. 270, pl. 15, figs. 6-9) from the Jurassic of New 

Zealand was designated the type species (pl. 1, figs. 24, 

25). Detailed comparisons were made with the pelecypods Entomonotis Marwick (1935, p. 298) and Echinot·is. Marwick's definition, based solely on the type 

species, was modified slightly in 1953 (p. 95) when he 

included in the genus two other species from N e"\v 

Zealand. The modified definition is as follows : 

Shell of moderate size, obliquely ovate, inequivalve, right 

valve less inflated than left, posterior wing well developed. 

Sculpture of numerous close wavy radials, left [sic right] valve 

with weaker radials or smooth. Right valve with small anterior ear, bounded by a deep groove without a deep notch. 

This definition does not mention the charaeteristics of 

the hinge area which Marwick (1935, p. 302) had described in his original definition as follows: 

Hinge area narrow, edentulous. Ligament set in a strongly 

and regularly grooved triangular-pit, the base of which is about 

half the length of the posterior dorsal margin. Left valve with 

the hinge margin sinused upwards and inwards immediately in 

front of the umbo, but further forward the margin projects outwards and bears several deep grooves. 

These characteristics of the hinge area of Otapiria 

11wrshalll (Treclnnann) were depicted in drawings 

(Marwiek, 1935, pl. 36, figs. 28-32, 34, 35) for cmnparisons with similar drawings of Ent01nonotis (Marwick, 

Bl 
B2 CONTRIBUTIONS. TO PALEONTOLOGY 

1935, pl. 35, figs. 13~ 17, pl. 36, figs. 18-24, 33), and 

Echinotis (Marwick, 1935, pl. 36, figs. 25-27). They 

have not yet been found as well preserved on any other 

species of 0 tapiria. 

The additional species of Otapiria subsequently diseovered in northeastern Siberia (Pchelintseva, 1955, p. 

213; Zakharov, 1962, p. 25-29; Vozin and Tikhomirova, 

1964, p. 18) and in Alaska (table 1) show that the genus 

is characterized by an obliquely elongate :form, a weakly 

convex to flat right valve, wavy radial ribs of irregular 

strength and spacing, low broad irregularly spaced concentric ribs, a narrow endentulous hinge, a small byssal 

ear on the right valve, and a :fairly distinct posterior 

wing that merges evenly with the body of the shell. The 

posterior wing ranges in lengtJ1 from :fairly short to 

1noderate. 

TABLE I.-Distribution of Otapiria in space and time 

Species of Otapiria Distribution 

0. ussuriensis (Voronetz) __ Northeastern Siberia ____ _ 0. dissimilis (Cox) _________ New Zealand ____________ _ 

0. marshalli (Trechmann)_ New Zealand and New 

Caledonia. 

O.limaeformis Zakharov ___ Northeastern Siberia ____ _ 

0. tailleuri Imlay, n. sp ____ Northern Alaska ________ _ 

0. masoni Marwick ________ New Zealand ___________ _ 

0. sp. undet_______________ East-central Alaska _____ _ 

Age 

Late Triassic (Karnian). 

Late Triassic (Rhaetian). 

Early Jurassic (Hettangian and Sinemurian). 

Early Jurassic (Hettangian and Sinemurian). 

Early Jurassic to middle 

Bajocian. 

Late Jurassic (Kimmeridg- ian). 

Unknown. 

CHARACTERISTICS OF LUPHERELLA IMLAY, N. GEN. 

Lupherella is characterized by a broadly ovate t,o 

obliquely ovate :fonn, a gently convex right va'lve that 

is slightly less convex than the left valve, highly variable radial and concentric ribs, fairly long posterior 

wings, a weak anterior wing on many left valves, a 

byssal ear on the right valve, and a fairly long dorsal 

margin. The hinge is probably edentulous, considering that the right and left valves have not been found 

together. The type species of L1.tpherella is Daonella 

boechijor1nis Hyatt (1894, p. 415; Crickmay, 1933, p. 

53, pl. 14, figs. 8-13). The genus is named in honor of 

Ralph L. Lupher in recognition of his excellent pioneering studies of the Jurassic sediment1a1--y rocks in eastcentral Oregon. 

Lupherella resembles the genus 0 tapiria Marwick in 

most respects. It differs by having a s1naller and less 

obliquely elongate shell, a 1nuch longer dorsal margin 

relative to the shell length, a longer posterior wing, 

finer and more numerous concentric ribs, and ~a snmll 

anterior wing on 1nany left valves. Lupherella differs 

from M onotis mainly by having a less obliquely elongate 

shape, more conspicuous concentric ribbing, and less 

prominent radial ribbing. It differs from jjf elea.grinella 

by being somewhat larger, by having an obliquely elongate instead of orbicular or subquadrate outline, a more 

convex and more strongly ribbed right valve, more 

wavy radial ribbing, more conspicuous concentric ribbing, and a long instead of a short posterior wing. An 

anterior wing on the left valve, as in Lupherella, is 

present on some left valves in both 11/ onotis (Marwick, 

1935, p. 298) and 111 eleagrinella (Cox, 1940, p. 90, 91). 

BIOLOGICAL RELATIONSHIPS 

0 tapiria and LuphereUa resemble each other so much 

that they may reasonably he placed in the same family, 

but that f~amily assignment is uncertain. 0 tapiria was 

placed in the Pteriidae by Marwick ( 1935, p. 302; 195:3, 

p. 53, 94) and by Cox and Arkell (1948, p. 7) and in the 

Monotidae by Zakharov ( 1962, p. 23-25), and was discussed under the Monotidae by Ichikawa ( 1958, p. 166-

168). The genus was not assigned to the Monotidae 

by Ichikawa ( 1958, p. 198) because it has a deep ligamenta! pit, which according to Ichikawa (1958, p. 166 

and footnote at bottom of p. 168) is probably absent in 

the Monotidae. Otapiria was compared by Marwick 

( 1935, p. 302) with the genera Entmnonotis Marwick 

(1935, p. 298) and Echinotis Marwick (1935, p. 301). 

Of these, Entmnonotls is now considered 1a subgenus of 

111 onotis by Ichikawa ( 1958, p. 170) and a synonym of 

111 onotis by most authorities (Muller, 1938; Marwick, 

1953, p. 57; Tozer, 1961, p. 107; Westermann, 1962, p. 

756). Echinotis is recognized as a synonym of Meleagrinella Whitfield ( 1885, p. 71; Oox, 1941; Marwick, 

1953, p. 94). 

The biological affinities of 0 tapiria were stated by 

Marwick ( 1935, p. 302) as follows : 

Otapiria is nearest to Entomonotis in general characters 

and may be the Jurassic descendent of that stock. Otapiria has 

much finer sculpture, an exceptionally ovate shape, and the 

hinge of the left valve has a sinus instead of a projection immediately in front of the ligament .and beak. The ligament-pit is 

more deeply entrenched ~than thmt of Entonwnotis, thus resembling Echinotis, but the well incised parallel grooves increase the 

affinity with Entomonotis. 

The anterior ear of the right valve of Otapiria shows important differences from that of Entomonotis being set more in the 

plane of the disc, the upper edge of which is consequently not 

bent inwards. 

Concerning these comparable genera, M eleagrinella 

(equals Echinotis of Marwiek) differs from Otapiria 

by being much smaller and by having an orbicular or 

subquadrate instead of obliquely elongate outline, much 

less \Va vy radial ribbing, less conspicuous concentric 

ribbing, and a nniCh shorter posterior wing. The genus 

JJf onotis resembles Otapiria considerably in size and 

shape. It differs by not having a deep ligan1ental pit, 

by its posterior ears generally merging less gradually 

with the body of the shell, by its radial ribs being 

eoarser, more regular in strength ·and spacing, and n1uch 

less wavy, and by its concentric ribs being fe\ver and less 

conspicuous. 
MESOZOIC PELECYPODS OTAPIRIA MARWICK AND LUPHERELLA_ IMLAY B3 

Another cmnparable genus is Pleu/rmny8idia Ichikawa 

(1954, p. 52-54), based on a single spec.ies, P. d1.tbia 

Ichikawa, from the Upper Triassic of Japan. This 

genus, according to its author, differs frmn jJf onoti8 by 

having a more convex right valve and 1nuch finer radial 

ribbing and consequently was assigned questionably to 

the Monotidae. Zakharov (1962, p. 25), however, considered Pleurmny8idia to be a synonym of Otapiria 

under the family Monotidae. Subsequently, some 

similar appearing pelecypods from the Upper Triassic 

of Siberia "\vere assigned toP. dubia< I chik~awa without 

reference to Otapirict (Vozin and Tikhomirova, 196± p. 

18, pl. 7, figs. 4-6) . These specimens, as well as the 

type specimens of P. dubia Ichikawa, differ from any 

described species of Otapiria by having an inflated right 

valve that is more convex than the left valve. 

COMPARISONS OF SPE.CIES 

The seven species of Otapiria listed herein 1nay be 

differentiated readily by the features Rhown in table 2, 

which is based on published descriptions and on observations. In addition, enough data are available for 

several species and :for Lupherella boechifor'lni8 

(Hyatt) to make the statiBtical comparisons shown in 

table 3. Such data are particularly valuable in comparing ratios, numbers, and dimensions. The most useful features in differentiating the species include the 

degree of convexity of the right valves, the strength and 

density of the radial and the concentric ribs, and the 

presence or absence of radical ribs on the right valves. 

Comparisons of all these features 1nake sharp distinctions between the species possible. 

For exa1nple, Otaph1ia u.s8urien.-;is (Voronetz) 

greatly resembles 0. lhna;eformi8 Zakharov and 0. 

tailleuri Imlay, n. sp. in size, shape, and ribbing, but it 

has a 1nuch more convex right valve. 0. dissimilis 

(Cox) differs from 0. 1narslwlli ( Trechmann) by having a nearly smooth right valve. It differs from 0. 

masoni Marwick by being 1nore obliquely elongate and 

by having faint radial ribs on the right valve. 0. 

marshalli (Trechmann) is characterized by its large 

size, strong posterior elongation, and n1oderately strong 

but densely spaced ribs on both valves. 0. tailleu.ri linlay, n. sp. di:ffeus frmn 0. lin~Jaeform,i.s Zakharov by 

having distinct radial ribs on its right valve, 1nuch 

denser radial ribbing on its left valve, and a less variable shape. Lupherella boechiformi8 Hyatt. is readily 

distinguished from all species of Otaph·ia by its long 

dorsal margin. 

SYSTEMATIC DESCRIPTIONS 

Family MONOTIDAE Fischer, 1887 

Genus OT'APIRIA Marwick, 1935 

Otapiria tailleuri Imlay, n. sp. 

Plate 1, figures 1-23; plate 2, figure 32 

This species is represented in collections from northern Alaska by 40 right valves, 70 left valves, and many 

small immature specimens and fringements. Almost all 

right and left valves occur separately. 

The shell is smaller than average size for the genus. 

It is strongly inequilateral, weakly inequivalve, obliquely ovate in outline, moderately to strongly extended posteriorly, and is compressed but attains maxinnun inflation in the dorsal fourth of the umbonal 

regwn. 

The left valve ranges frmn gently to weakly convex, 

is a little larger and more convex than the right valve, 

and is most convex in the mnbonal region. Its length 

exceeds it height on all speci1nens. The ratio of height 

to length, based on some of the largest and best preserved left valves, ranges frmn 70.5 to 96.5. The beak 

is lJs-1,4 the length of the shell from the anterior end. 

It is projecting, strongly incurved, pointed, and 

directed slightly anteriorly. The dousal margin is 

straight and is a little less than half as long as the 

length of the shell. The anterior end is 1nodera.tely 

to narrowly rounded and projecting. The ventral 

margin is broadly rounded. The posterior margin 

ranges frmn broadly to rather narrowly rounded. A 

posterior wing, visible only on three left valves, is 

moderately short and merges evenly with the body of 

the shell. 

The right valve ranges frmn weakly convex to nearly 

flat. The ratio of height to length of the largest specimens ranges from 68.9 to 90.9. The beak is inconspicuous and barely projects above the dorsal margin. 

The outline of the right valve is nearly the same as that 

of the left valve. A posterior wing is well developed. 

An anterior byssal ear, preserved only on two small 

right valve_s (pl. 1, figs. 10, 12), is moderate in size and is 

separated from the 1nain body of the shell by a deep 

groove. One of the specimens (pl. 1, fig. 10) also bears 

an indentation that is probably a byssal notch. An 

anterior ear is not visible on any of the large right 

valves. 

The shell is ornamented with sharp fine closely spaced 

radial ribs and with low broad irregularly spaced concentric ribs. The radial ribs are appreciably stronger 

on left valves than on right valves. On both valves 

they are sharpest and most closely spaced on immature 
TABLE 2.-Comparisons of Triassic and Jurassic species of Otapiria 

Dimensions of largest Ratio of Radial ribbing Concentric ribbing known left valves (mm) length Posterior 

Species of of dorsal Convexity of elongation of 

Otapiria margin to right valve left valve 

Length Height Convexity length of Left valve Right valve Left valve Right valve 

shell 

---

0. ussuriensis 34 38 7. 5 About 4L. Slightly less Moderate .. ___ Fine, dense. __ FainL. _______ Broad and Fairly broad._ 

(Voronetz). than left sparse. valve. 

0. dissimilis 33 28 5.0 About 42 .. Less than left Strong ________ Coarse irregu- Faint__------- Low, broad, Weak round, (Cox). valve. lar, dense. irregular, irregular. 

sparse. 0. marshalli 54 37 7.0 34-50 ______ Less than left Strong ________ Moderate in Moderate, Low, broad, Weak _________ (Trechmann). valve. strength, dense. sparse. 

very dense. 

0. limaeformis 28 25 Unknown. Unknown. Weakly con- Varies from Fine, dense ... Faint or Low, broad, Weak, sparse .. Zakharov. vex to near- ovate to absent. sparse. ly flat. moderately 

elongate. 0. tailleuri 26.2 18.5 2.2 40-45 ______ Weakly con- Moderate to Fine, dense ___ Finer than on Low, broad, Same as on Imlay, n. sp. vex to near- strong. left valves, moderately left valve. 

ly flat. dense. dense. 

0. masoni 33 29 4.0 About 47.. Less than Moderate. ____ Moderate in Absent ________ Low, broad, Wide, flat, Marwick. left valve. strength, sparse. separated irregular, by deep 

dense. grooves. 0. sp. undet .. __ 17 Hi Unknown Unknown. Less than Moderate _____ Fairly fine Similar to Fairly low, Same as on left valve. and dense. that on left broad, left valve. 

valve. sparse. 

----

Length of posterior ;Position of wing 

beak from 

anterior 

end Left valve Right 

valve 

}4-}3 Fairly Fairly short. short. 

7~-7f; Fairly Fairly short. short. 

73 Moderate. Fairly 

short. 

73-}2 Moderate. Moderate. 

H-73 Fairly Fairly short. short. 

74-73 Short. ____ Not 

known. 

About 73 Fairly Fairly 

short. short. 

Source of data 

Pchelintseva 

(1955, p. 213, 

pl. 1, figs. 1-10, 

pl. 2, figs. 1-2). 

Marwick (1953, 

p. 59, pl. 3, 

figs. 10-12). 

I. G. Speden (written 

commun. 

March, 1965). 

Zakharov(1962 

p. 25-29, 1 pl. 2 text-figs). 

Presented 

herein. 

Marwick (1953 

p. 95, pl.ll, figs. 10, 11) 

Presented 

herein. 

Oj 

~ 

0 

0 

z 

~ t:d 

~ ~ 

0 

z 

l/1. 

8 

0 

1-d 

> 

~ 

t_:l:l 

0 

~ 0 

t'i 

0 

~ 

~ 
MESOZOIC PIDLECYPODS OTAPIRIA MARWIOK AND LUPHERELLA IMLAY B5 

TABLE 3.-Comparisons of measurements of some Jurassic species 

of Otapiria and Lupherella 

Otapira Otapiria Otapiria Lupherella Characters marshalli limaejormis tailleuri boechiformis 

(Trech- Zakharov Imlay, (Hyatt) 

mann) n. sp. 

Maximum dimensions (mm): Length: Left valve _______________ 54.1 28.6 26.2 13.2 Right valve ______________ 57.0 23.0 20.0 16.0 Height: 

Left valve ___ ------------ 36.9 25.0 18.5 22.4 Right valve ______________ 34.7 20.8 16.5 13.1 Length of dorsal margin (mm): 

Left valve ____ --------------- 12. Q-18. 5 INK 6. o-7(?) 4. 6-8.2 Right valve __________________ 7. 6-14. 2 NK 5. 5-9.2 4.8-10.5 Ratio of width (convexity) to length: Left valve ___________________ 12.8-18. 5 NK 5. 5-18.1 15. Q-23. 2 Right valve __________________ 8. 2-16.4 NK 4. 8-8.5 8.1-14. 7 Ratio of height to length: Left valve ___________________ 60.9-83.3 55.0-167.0 70.5-96.5 86.3-93.9 Right valve __________________ 60.8-76.2 59.0-156.0 69.0-91.0 81.8-100.0 Number of radial ribs: Left valve ___________________ 54-105 90-100 105-170 38-77 Right valve __________________ 52-95 (2) 8Q-120 36-85 Number of concentric ribs: 

Left valve ____ --------------- 7-11 7-10 11-17 16-32 Right valve __________________ 7-10 6-10 9-13 17-44 Width of radial interspaces com- pared with ribs ________________ ~~-72 31.0 31.0 1-1 to 3-1 

I Not known. 2 Absent or faint. 3 Or slightly wider. 

specimens and on the umbonal and anterior parts of 

adult shells. On these parts the radial ribs are separated by interspaces that are about as wide as the ribs, 

but posteriorly the ribs become weaker and more widely 

spaced, and gradually become indistinct near the postero-dorsal margin. The radial ribs are fairly straight 

on the umbones and on specimens with few concentric 

ribs, but are generally wavy where they cross the concentric ribs. New radial ribs arise 1nostly by intercalation, but some arise by bifurcation. The number of 

radial ribs ranges from 105 to 170 on left valves and 

from 80 to 120 on right valves. The number of concentric ribs ranges from 11 to 17 on left valves and from 

9 to 13 on right valves. The number of radial or concentric ribs is clearly related both to size and to individual variation. The largest specimens have the most 

ribs, but some small specimens have more ribs than 

other, somewhat larger ones. 

The ligamenta] area and muscle scars are unknown. 

The shell, represented by a few fragments, is very thin. 

The immature left valves of this species are all fairly 

convex, whereas only a few adult specimens are as convex and then only in the umbonal region. Most of· the 

large left valves, however, have been crushed, and some 

of the beaks have been sharply bent. It seems probable, 

therefore, that most of the large specimens were more 

convex in life than they are now. 

The immature specimens of 0. tailleuri Imlay, n. sp. 

show considerable resemblance to lf,f elegrinella. The 

resemblance is closest in those specimens that have few 

concentric ribs and, consequently, fairly straight radial 

ribs. However, such specimens are generally associ237-493 0 - 67 - 2 

ated with others that have many concentric ribs and 

rather wavy radial ribs, features which are characteristic of 0 tapiria. 

The Alaskan species closely resembles 0. linwefonnis 

Zakharov (1962, p. 25-29, pl. 1, figs. 1-16, pl. 2) from 

the basal Jurassic of northeastern Siberia in size and in 

the fine ribbing of its left valve. It differs by being a 

little smaller, by having a much less variable shell outline, by its right valve bearing distinct radial ribs instead of being smooth or bearing only faint radial ribs, 

and by its left valve having much denser radial ribbing. 

These differences, as shown in tables 2 and 3, are greater 

than is suggested by visual comparisons of the illustrations of the two species. For example, the left valves 

of 0. lhnaefornds bear 90-100 ribs, whereas the left 

valves of 0. tailleuri bear 105-170 ribs. Concerning 

variation in shell outline, the left valves of 0. limaefor'1nis have a ratio of height to length that ranges 

from 55.0 to 167.0, whereas in 0. tailleuri the range is 

from 70.5 to 96.5. The greatest difference between the 

two species, however, is in the absence to near absence 

of radial ribs on the right valves of 0. limaeforn~i8. 

This difference cannot reasonably be ascribed to defective preservation of the right valves of 0. lin~aefornuirs Zakharov because all illustrated valves appear 

to be fairly well preserved, and m9re than 300 specimens of both valves were available for study (Zakharov, 

1962, p. 26) . Furthermore, several other species of 

Otapiria besides 0. linwefm"1nis have similarly ornamented right valves. Thus, 0. dissirmilis (Cox) (Marwick, 1953, p. -59, pl. 3, figs. 10-12) and 0. U881J/riensis 

( V oronetz) ( Pchelintseva, 1955, p. 213, pl. 1, figs, 1-10, 

pl. 2, figs. 1-2; V ozin and Tikhomirova, 1964, p. 18, pl. 

7, figs. 1-3) bear only faint radial ribs on their right 

valves, and 0. 1nasoni Marwick ( 1953, p. 95, pl. 11, figs. 

10, 11) bears no radial ribs on its right valve. 

The Alaskan species also resembles Otapiria ussuriensis (Voronetz), just mentioned, in the density of ribbing 

on its left valves; but it is much less elongate posteriorly, 

has a less convex right valve, and has much stronger 

ribbing on its right valve. The only other similar species 

is 0. 11Wr'8halli (Trechmann) (1923, p. 270, pl. 15, figs. 

6-9; Marwick, 1935, p. 302, figs. 10, 12, 28, 32, 34, 35; 

1953, p. 95, pl. 11, figs. 7, 8) from the basal Jurassic of 

Ne'v Zealand and New Caledonia. That species resembles 0. tailleurl Imlay, n. sp. in variability of shell outline, in convexity, and in the presence of conspicuous 

ribbing on its right valves. It differs, however, by being, 

on the average, t"\vice as large, by having much sparser 

and coarser radial ribbing, and by having ribs two to 

three times 'vider than the interspaces instead of about 

equal in width. 
B6 CONTRIBUTIONS TO PALEONTOLOGY 

The fossils found with Otapiria taillmtri Imlay, n. sp. 

in northern Alaska include I noce1·amms, Lin1a.?, Oxytoma, ammonite frag1nents, fish scales, and Radiolaria. 

In addition, belemnites are fairly common in some associated shales. The best preserved/ nocermnus at USGS 

Mesozoic locality M2451 are from beds approximately 

35 feet higher than the beds containing Otapiria, but 

I noceramlus shell prisms are abundant in thin sections of 

slabs that bear Otapiria (Mesozoic locs. M2318 and 

24060). One ammonite also occurs in the same slab as 

Otapiria (Mesozoic loc. 29282). These associations indicate that 0 tapiria belongs to the same assemblage as 

I nocera1nus and the ammonites. 

The age of the beds containing 0 tapiria tailleuri Imlay, n. sp. is either late Early Jurassic (Toarcian) or 

early Middle Jurassic (Bajocian), or both. An age not 

older than Toarcian is shown by the association of 

Otapiria i11 the same beds with true Inoceramus, which 

according to Hayami (1960,. p. 292, 294; 1961, p. 817) 

did not originate until Toarcian time. An age not 

younger than early middle Bajocian is shown by the 

close resemblance of some of the lnoceran-uus (USGS 

Mesozoic locs. 24060 and M2451) to/. lucifer Eichwald, 

which in southern Alaska occurs only in the lower part 

of a sequence of Bajocian age (In1lay, 1955, p. 86; 1964, 

p. B18). 

A Toarcian to early Bajocian age for the Otapiriabearing beds is also indicated by the presence of certain 

fragmentary ammonites at USGS Mesozoic localities 

29281 and 29282. These am1nonites are highly evolute 

and have strong, straight, simple, widely spaced, radialtrending ribs. In lateral view they resemble Tmetocel'as 

of early Bajocian age and Oatulloceras or Dumortieria 

of late Toarcian age. Unfortunately, the preservation 

of the ammonites does not permit positive generic determination. Their presence is excellent evidence, however, 

that the beds bearing 0 tapirht are not older than 

Jurassic. 

In summation, the presence of Inoceramus cf. I. lucifer Eichwald is good evidence of an early to 1niddle 

Bajocian age for at least part of the thin unit of organic 

shale containing Otapiria. As the best preserved specimens of I noce1'amus were obtained frmn slightly higher 

beds than Otapiria, it is possible that other ages are 

represented. Nonetheless, the presence of I noceram/us 

shell prisms in the same slabs as Otapiria indicates an 

age not older than Toarcian. An age near the ToarcianBajocian boundary is indicated also by the amn1onites 

associated with Otapi1'ia. 

The species is named in honor of I. L. Tailleur of the 

U.S. Geological Survey, who collected most of the speciInens now available for study. 

Types.-Holotype USNM 153276; paratype USNM 

153272-153275, 153277-153294. 

Ocm.l,rrrences.-Otapiria tailleun: Imlay, n. sp. has 

been obtained in northen1 Alaska frmn organic shale 

that directly overlies fossiliferous Upper Triassic beds 

and has generally been n1apped as part of the Shublik 

Fonna:tion. The species occurs at the U.S. Geological 

Survey Mesozoic localities described below. Nu1nbers 

1-5 preceding the locality descriptions refer to numbers shown in figure 1, an index Ina.p of Alaska. The 

letter "M" preceding the Mesozoic locality number 

shows that the fossils are recorded at the Menlo Park 

office. 

1. Mesozoic loc. 24060 (51 ATr 94). I. L. T·ailleur, 1951. Limestone on east side of Ipnavik River. Lat 68°40.50' N., 

long 157°03.75' W. 

2. Mesozoic loc. M2451 ( 64 T 305 and 64 AS 321). Sigmund 

Snelson and I. L. Tailleur, 1964. Organic shale, chert, 

and limestone :about 60 feet thick which may be conformable downward with the Shublik F1ormation and which is 

les•s 1than 20 feet below a clay shale unit that contains 

Buchia of Early Cretaceous (Valanginian) age. Lat 

68°37.62' N., long 156°43.05' W., NID14 see. 36 T. 9 S., R. 21 

W., Howard Pass quad. 

2. :Mesozoic Joe. 292-80 ( 65 ATr 73.5) . I. L. Tailleur, 1965. Same 

locality data as Mesozoie loe. M2451. 

3. Mesozoic loc. :M2318 (64 APa 224). "\V. W. Patton, Jr., 1964. 

Cutbank on east side of Tiglukpuk Creek, south flank of 

Tiglukpuk Creek anticline. Lat 68°21.24' N., long 151 o 

52.35' W., Chandler Lake quad. 

3. Mesozoic loc. 29281 (65 ATr 123B). I. L. Tailleur, 1965. 

Talus on cutbank at Mesowic loc. M2318. 

3. Mesozoic loc. 29282 ( 65 ATr 149.4). I. L. Tailleur, 1965. 

Float on southwest wall of Firestone Creek (tributary of 

Tiglukpuk Creek) just north of mountain front, about 5 

miles south-southeast of loc. 29281. Lat 68°18.32' N., long 

151 °48.3' "\V., Chandler Lake quad. 

4. Mesozoic loc. M2317 (64 APa 206). W. ·w. Patton, Jr., 1964. 

Cutbank on east side of Erratic Creek. Lat 68°23.25' N., 

long 150°5·2.05.' ·w., Chandler Lake quad. 

4. Mesozoic loc. 29284 (65 ATr 152.2.2). I. L. Tailleur, 196•5. 

Oaleareous layer and lens 6 feet above top of Triassic beds. 

Cutbank on west side of Erratic Creek in anticlinal nose. 

Lat 68°23.05' N., long 150°52.1' "\V., Ohandler Lake quad. 

4. Mesozoic loc. 29287 ( 65 ATr 153.2). I. L. Tailleur, 1965. 

Dark limestone nnd shale appa·rently withinlO feet of top of 

Triassic beds. Outcrop on eas't wall of Erratic Creek, about 

half a mile downstream from Mesozoic loc. 29284 at about 

same location as M2317. 

5. Mesozoic loe. 29285 (65 ATr 159.2). I. L. Tailleur, 1965. 

Lower 6 feet of shale directly overlying the Triassic. Cutbank and cliff in nor•th side of Atigun Gorge. Lat 68°29.0' 

N., long 149°14' "\V., Phillip Smith Mountains quad. 
MIDSOZOIO PELECYPODS OTAPIRIA MARWIOK AND LUPHERELLA. IMLAY B7 

156° 152° 148° 132° 

T I C 0 C E 

EXPLANATION 

U. S. Geological Survey Mesozoic 

localities, described in detail 

in text at end of species descriptions: 

1. 24060 

2. M2451 and 29280 

3. M2318, 29281, and 29282 

4. 2317,29284, and 29287 

5. 29285 

PACIFIC 

FIGuRE 1.-0ccurrences of the pelecypod Otapiria in Alaska. 

Otapiria sp. undet. 

Plate 2, figures 28-31 

Ota-piria is represented in colledions frmn southeast 

of Nation in east-central Alaska by seven fairly well 

preserved left valves and five right valves. All left and 

right valves occur separately. 

The shell closely resmnbles that of 0. ta.illeuri Imlay, 

n. sp. in size, shape, and convexity, and in the presence 

of a byssal ear on the right valve. It differs mainly by 

having much stronger and fe,-ver radial ribs, slightly 

stronger concentric ribs, and ribbing on the right valve 

as strong 'as that on the left valve. On the two left 

valves illustrated, the larger has about 78 radial ribs 

and the smaller about 85 Dadial ribs. These numbers 

are well below the range of variation of 105-170 for 0. 

taille·nri Imlay, n. sp. (table 3). One of the two small 

right valves illustrated has about 50 and the other about 

35 radial ribs. These numbers are somewhat less than 

on comparable s1nall right valves of 0. ta.illeuri. The 

width of the radial interspaces compa.red to the width 

of the ribs is about the same on both species. 

The greater coarseness of ribbing of the specimens of 

Otapiri.a from east-central Alaska suggests that they are 
B8 CONTRIBUTIONS TO PALEONTOLOGY 

different a,t least subspecifically from 0. tailleuri Imlay, 

n. sp. from northern Alaska, but not enough speci1nens 

are available to show their range in variation. The 

specimens, however, do suggest that the coarseness 

in ribbing is intermediate between that of 0. tailleuri 

and 0. marshalli (Trechmann). 

The age of the specimens of 0 tapiria from eastcentral Alaska is not known because the specimens were 

obtained as float on a mudslide. Nonetheless, their resemblances to 0. tailleuri Imla,y, n. sp. suggest a similar 

Jurassic age. Also, the presence on the same m udslide 

of the crinoid Pentaerin'us S'ltbangularis var. alaska 

Springer (identified by Porter M. l{ier of the U.S. N ationa! Museum) indicates that rocks of Early Jurassic 

age exist in the area. Such an age is based on the fact 

that this crinoid in northern Alaska has been found only 

near the base of the Jurassic l{ingak Shale, and on the 

Oanning River it occurs (Mesozoic loc. 21025) many 

hundreds of feet below beds that have furnished fossils 

(Mesozoic loc. 24035) of early Bajocian age (Imlay, 

1952, p. 983; Keller, Morris, and Detterman, 1961, p. 192, 

193). 

Figured specinwns.-USNM 153295. 

Ocourrenoe.-U.S. Geological Survey Mesozoic loc. 

M1717. N. J. Silberling, 1962. Mudslide on west side 

of Michigan Creek about 300 yards upgtream from 

prominent outcrop of Tahkandit limestone. Center 

S!4NE!4NE% sec. 23, T. 4 N., R. 29 E., about 3 miles 

east-southeast of Nation, Charley River A....:2 quad. 

(1: 63,360), upper Yukon Valley, Alaska. This locality 

is shown as number 6 in figure 1. 

Genus LUPHERELLA Imlay, n. gen. 

Lupherella boechiformis (Hyatt) 

Plate 2, figures 1-27 

Daonella boechiformis Hyatt, 1894 Geol. Soc. America Bull., 

v. 5, p. 415. 

Daonella ca1·dinoides Hyatt, 1894, Geol. Soc. America Bull., v. 5, 

p. 416. 

Daonella boechiformis Hyatt. Crickmay, 1933, U.S. Geol. Survey Prof. Paper 175-B, p. 53, pl. 14, figs. 8-13. 

Daonella cardinoides Hyatt. Crickmay, 1933, U.S. Geol. Survey 

Prof. Paper 175-B, p. 53, pl. 14, figs. 18-23. 

This species in the collections of the U.S. Geological 

Survey is represented by a few specimens from partially 

metamorphosed noncalcareous siltstone in the Sailor 

Canyon Formation of east-central California, by a few 

speci1nens fron1 noncalcareous mudstone in theW allowa 

Mountains in northeastern Oregon, and by hundreds of 

specimens frmn the Nicely Formation of Lupher (1941) 

in east-central Oregon. In the Nicely Formation the 

species occurs in black calcareous concretions and in 

calcareous mudstones. The specimens from California 

are all distorted, and those from the 1nudstones in Oregon appear to be somewhat crushed. In contrast, the 

speeimens from concretions are undeformed and well 

preserved. 

The shell is inequilateral, slightly inequivalve, obliquely ovate to elliptical in outline, slightly extened 

posteriorly, and gently convex. 

The left valve is slightly more convex than the right 

valve and is most convex in the umbonal region. Its 

length exeeeds its height on all speeimens. The ratio 

of height to length, based on 1neasurements of 10 wellpreserved specimens, ranges fron1 86.3 to 96.5. The 

beak is situated JA-215 of the length of the shell from 

the anterior encl. It is pointed, projects forward and 

in ward, and rises slightly above the hinge line. The 

dorsal margin is straight and is about two-thirds as 

long as the shell. The anterior n1argin is evenly 

rounded and slightly projecting. The ventral margin 

is broadly convex. The posterior margin is generally 

1nore broadly rounded than the anterior 1nargin. The 

left valve has a posterior wing that is moderately long, 

1nerges evenly with the body of the shell, and is rather 

indistinct on n1ost specimens. A short weak anterior 

wing is present on many small left valves and is separated frmn the body of the shell by a shallow round 

depression. 

The right valve is similar in size and shape to the left 

valve, but is rounder in outline, has a smaller and less 

projecting beak, and is a little less convex. The lesser 

convexity of the right valve, ho·wever, is based on measurements of many single valves because complete shells 

have not been found together. The right valve has a 

1noclerately long but weakly defined posterior wing and 

a small anterior ear that is bounded by a deep groove. 

The anterior ear has been noted on 20 specilnens. 

The shell is ornamented with highly variable radial 

and concentric ribs, of which the radial ribs predominate. The ribbing as a whole is nearly as strong on the 

right valve as on the left. 

The radial ribs are mostly fine and sharp but they 

vary markedly in strength, width, and spacing both on 

the same specimens and on different specimens. They 

range also from nearly straight to rather wavy. Generally they are straightest and sharpest on the umbonal 

and medial parts of the shell, become broader and more 

wavy toward the margins, and fade out dorsally on the 

anterior and posterior margins. The radial ribs are 

most wavy where the concentric ribs are strongest and 

are somewhat stronger where they eross the eoncentric 

ribs than in the concentric interspaces. The width of 

the radial ribs ranges from a little more than the width 

of the interspaces to about one-third the width of the 

interspaces. New radial ribs arise by furcation and by 

intercalation in an irregular manner. The number of 
MESOZOIC PffiLEOY,PODS OTAPIRIA MiARW,IOK AND LUPHERELLA IMLAY B9 

radial ribs, as seen on 20 specimens of various sizes, 

ranges from about 35 to 85 and differs considerably in 

specimens of the same approximate size, but it is greatest on the largest specimens. The number of radial ribs 

appears to be about the same on both valves. 

The concentric ribs vary considerably in width, 

strength, spacing, and number. Near the beak they are 

rather fine and are widely but variably spaced. Toward 

the margins of the shell they become broad, closely 

spaced, and much wider than the interspaces. The 

concentric ribs are decidedly stronger and broader toward the posterior margin than toward the other margins, and are much more conspicuous on some specimens 

than on others. The number of concentric ribs, as based 

on counts of 20 specimens, ranges from 16 to 44 and differs considerably on specimens of the same approximate 

size, but it increases generally with increasing size and 

is greatest on the largest specimens. 

The ligament area and muscle scars are unknown. 

The shell, represented by fragments on a few specimens, 

is very thin. 

"Daonella" boechiformis Hyatt was assigned by 

Hyatt (1894, p. 415) to the Triassic genus Daonella., 

presumably on the basis of its general shape and ornamentation. The type specimens, however, are poorly 

preserved and distorted and do not show the hinge area. 

The much better preserved specimens from the Nicely 

Formation of eastern Oregon show that an assigmnent 

to Daonella is not possible because of the presence of 

fairly long posterior wings and of a small anterior 

bysal ear. 

Lupherella boechiforrnis (Hyatt) in Oregon and 

California is associated with m'any ammonites of late 

Pliensbachian age, including the genera L~iparocera.'3 

(Becheicera8), Reynesocera8, Prodactylioceras, A.rieticera8, Fontanellicera8, and Leptaleocera8. In the 

Nice'ly Formation of east-central Oregon it is also commonly associated with rhynochonellid brachiopods and 

uncommonly with fish remains, ammonite aptychii, 

belemnite guards, small gastropods, ~and the pelecypods 

Ostrea, Entoliunt, Oamptonectes, Owytoma, lJ,f odiolu8, 

and Pinna. All these occur both in concretions and in 

the surrounding black mudstone. The variety of organisms present is similar to that associated with Otapiria 

in Upper Triassic 'and Lower Jurassic beds in New Zealand (Marwick, 1953, p. 19, 20). 

Lupherella boechiformis (Hyatt), on the basis of 

lithologic facies and fauna:l association, probably lived 

in a fairly shallow sea in which organic mud was accumulating and which locally in Oregon contained a 

consid~erable variety of mud-dwelling, attached, and 

free-swimming organisms. 

Types.-Lectotype USNM 153296; syntypes USNM 

30189, 30191; hypotypes USNM 153297--153316; hypotypes California Aoad. Sci., 1'2778, 12779. 

Occurrences.-Lupherella boechiforrnis (Hyatt) has 

been found only in two areas in eastern Oregon and in 

one area in California, as shown in figure 2. In northeast Oregon it occurs throughout about 520 feet of unnamed partially mebamorphosed beds exposed on the 

northern front of the Wallowa Mountains about 5¥2 

1niles S. 5-:P W. of the center of Enterprise (No.1 in fig. 

2) . In east-central Oregon near Izee it occurs throughout the thin Nicely Formation (No. 2 in Fig. 2). In 

east-central California it occurs about 2,000 feet above 

the base of the Sailor Canyon Formation in Sailor 

Canyon (No. 3 in fig. 2). 'The exact location in California is shown in figure 6.1 of a paper by Clark, Imlay, 

McMath, and Silber ling (1962, p. B-16). Descriptions 

of the U.S. Geological Survey Mesozoic localities in 

which L. boechiforrrw's (Hyatt) has been found are 

given below. 'The numbers 1-3 preceding the descriptions refer to the numbers shown in figure 2 and to the 

three 1areas just mentioned. 

116° 

-----~-

I 

I 48° 

I 

I ... .... 

S H I N G T 0 N I \ 

I ... .,., 

I ) ~------\ ) _..... ' 

\ ~/\ 

.1 I 

) 

0 R E G 0 N / I D A H 0 ( 

.2 ' 44° 

______ I L---

1 EXPLANATION I 

40° 

I U.S. Geological Survey Mesozoic 1 

I localities, described in detail \ 

< in ~e~t at end of species de- 1 1 0 scnptwns: 1 

I < 1. 28807, 28808, 28809, 

;;.. and 28820 r---'1<:----------+1 ~ 2. 25819, 26740, 26745, 

1 26747, 27358, 27360, 

CALIFORNIA 

•3 1 27378, 29213, 29214, ~ 29215, 29221, and 

' 29222 "'- 3. 574 and 2464 

FIGuRE 2.-0ccurrences of Lupherella boechifot·mis (HyaU) in 

Oregon ancl California. 
BlO CONTRIBUTIONS, TO PALEONTOLOGY 

1. Mesozoic loc. 28807. Bruce Nolf, Tracy Vallier, W. H. Taubeneck, and R. W. Imlay, 1963. Northeast side of Sheep Ridge 

near center N'V%NW1A, sec. 19 (unsurveyed), T. 2 S., R. 44 

E., Wallowa County, Oreg. Unnamed beds from 820 to 

1,030 feet above base of exposures. Highest elevation 6,960 

feet. 

1. Mesozoic loc. 28808. Same data as loc. 28807, but 760-820 

feet above base of exposures. 

1. Mesozoic loc. 28809. Same data as loc. 28807, but 510-710 

feet above base of exposures. 

1. Mesozoic loc. 28820. Bruce Nolf, 1962. Same data a~ loc. 

28807, but probably from entire sequence from 510-1,030 

feet above base of exposures. 

2. Mesozoic loc. 25819. R. E. Wallace and J. A. Calkins, 1955. 

NE1_4SE1_4 sec. 36, T. 16 S., R. 28 E., Grant County, Oreg. 

Nicely Formation of Lupher (1941). 

2. Mesozoic loc. 26740. W. R. Dickinson and W. R. Imlay, 1957. 

North slope of main fork of Rosebud Creek, S'V cor. sec. 36. 

T. 16 S., R. 28 E., Grant County, Oreg. Nicely Formation. 

Scattered concretions in roadcuts and on surface of ground. 

2. Mesozoic loe. 26745. R. W. Imlay, 1957. Head of west fork 

of Elkhorn Creek on Morgan Mountain, NElA, sec. 14, T. 17 

S., R. 27 E., Grant County, Oreg. 

2. Mesozoic loc. 26747. R. vV. Imlay, 1957. Roadcut in SE cor. 

sec. 29, T. 18 S., R. 26 E., Grant County, Oreg. Nicely 

Formation, lower third, about 50 feet south of contact with 

top of Suplee Formation. 

2. Mesozoic loc. 27358. R. W. Imlay and H. R. Christner, 1958. 

Rosebud Creek, center SWlA, sec. 2, T. 17 S., R. 28 E., Grant 

County, Oreg. Nicely Formation, about 100 feet above base. 

2. Mesozoic loc. 27360. R. W. Imlay, 1958. Ridge south of 

Caps Creek, SE"%NW1A, sec. 16, T. 17 S., R. 28 E., Grant 

County, Oreg. Nicely Formation, about 20 feet below top. 

2. Mesozoic loc. 27378. R. W. Imlay, 1958. Southeast slope of 

Morg,an Mountain at head of east fork of first small creek 

west of Elkhorn Creek, NElA, sec. 14, T. 17 S., R. 27 E., 

Grant County, Oreg. Nicely Formation, about 120 feet 

above base. 

2. Mesozoic loc. 29213. W. 0. Ross and R. W. Imlay, 1965. 

Head of Rosebud Creek, on east side of road just north of 

sharp bend from west to north, NE cor. sec. 2, T. 17 S .. 

R. 28 E., Grant County, Oreg. Nicely Formation, 50-60 feet 

above base. 

2. Mesozoic loc. 29214. W. 0. Ross and R. W. Imlay, 1965. 

Head of Rosebud Creek, on east side of a north-trending 

logging rood near intersection with east-trending logging 

road, in NW cor. sec. 1, T. 17 S., R. 28 E., Grant County, 

Oreg. Nicely Formation. 

2. Mesozoic loe. 29215. "\V. 0. Ross and R. W. Imlay, 1965. 

East slope of canyon draining north from Hole-in-theGround, in NE cor. sec. 35, T. 17 S., R. 27 E., Grant County, 

Oreg. Nicely Formation, about 160 feet above base. 

2. Mesozoic loc. 29221. W. 0. Ross, 1965. Near top of ridge 

half a mile southwest of South Fork of John Day River in 

west-central part SWlA, SE% sec. 25, T. 17 S., R. 27 E., Grant 

County, Oreg. Nicely Formation, 50-70 feet below top. 

2. Mesozoic loc. 29222. W. 0. Ross and R. W. Imlay, 1965. 

Concretion in old road in SE cor. sec. 29, T. 18 S., R. 26 E .. 

Grant County, Oreg. Nicely Formation, about 35 feet above 

base. 

3. USGS Mesozoic loc. 574. Waldemar Hndgren, 1890. Sailor 

Canyon near Sterretts mine (now called Trinidad mine on 

Royal Gorge 7¥2' quad.) in SE% sec. 35, T. 16 N., R. 13 E .. 

Pl~cer County, Calif. Sailor Canyon Formation. 

3. Mesozoic loc. 2464. Cooper Curtice, 1891. Sailor Canyon 

near Sterretts mine at same general location as Mesozoic 

loc. 574, Sailor Canyon Formation. 

LITERATURE CITED 

Clark, L. D .• Imlay, R. "\V., M6\1ath. V. E., and Silberling, N.J., 

1962, Angular uncomformity bet\veen Mesozoic and Paleozoic rocks in the northern Sierra Nevada, California in 

Short papers in geology, hydrology, and topography: U.S. 

Geol. Survey Prof. Paper 450-B, B15-B19. 

Cox. L. R.. 1940, The Jurassic lamellibranch fauna of Kuchh 

(Cuteh) : India Geol. Survey, Mem. Palaeontologia Indica, 

ser. 9, v. 3, pt. 3, 157 p., pls. 1-10. 

--- 1941, Notes on Jurassic Lamellibranchia, VII; On the 

identity of Ecldnois Marwick with JJieleagt·inella Whitefield: Malacalog. Soc. London Proc., v. 24, p. 133-135. 

Cox, L. R., and Arkell, vV. J., 1948-49, A survey of the Mollusca 

of the British Great Oolite Series * * * : London, Palaeontopographical Soc., pt. I. v. 102 (1948), p. 1-48; pt. II, v. 103 

(1949), p. 49-105 [1950]. 

Criekmay, C. H., 1933, Some of Alr)heus Hyatt's unfigured types 

from the Jurassic of California: U.S. Geol. Survey Prof. 

Paper 175-B, p. 52-64, pls. 14-18. 

Hayami, Itaru, 1960, Jurassic inoceramids in Japan: Tokyo 

Univ., Faculty Sci. Jour., see. 2, v. 12, pt. 2. p. 277-328, pls. 

15-18. 

--- 1961, On the Jurassic pelecypod fauna in Japan: T'okyo 

Univ., Faculty Sci. Jour., sec. 2, v. 13, pt. 2, p. 243-343, pl. 

14, fig, 1. 

Hyatt, Alpheus, 1894, Trias and Jura in the western States : 

Geol. Soc. America Bull., v. G, p. 395-434. 

Ichikawa, Koichiro, 1954, Late Triassic pelecypods from the 

Kochigatani Group in the Sakuradani and Kito areas, Toskushima Prefecture, Shikoku, Japan, Pt. 1: Osaka City 

Univ., Inst. Polytechnics Jour., ser. G, v. 1, no. 1, p. 35-55; 

v. 2, p. 53-70; pls. 1, 2. 

--- 1958, Zur Taxionomie und Phylogenie der triadischen 

''Pteriidae" ( Lamellibraneh.) mit besonderer Berlicksichtigung der Gattungen Claraia, Eunwrphofi8, OJ'ytoma und 

JJionotis: PalaeontographiC'a, v. 111, see. A. p. 131-208, pls. 

21-24. 

Imlay, R. ,V., 1952, Correlation of the Jurassic formations of 

North America, exclusive of Canada: Geol. Soc. America 

Bull., v. 63, no. 9, p. 953-992, 2 correlation charts. 

--- 195•5, ChaDaeteristic Jurassic mollusks from northern 

Alaska: U.S. Geol. Survey Prof. Paper 274-D, p. 69-96, pls. 

8-13. 

~-- 1964, Middle Bajocian ammonites from the Cook Inlet 

region, Alaska: U.S. Geol. Survey Prof. Paper ·H8-B, p. 

B1-B61, pls. 1-29, figs. 1-G. 

Keller, A. S., Morris, R. H., and Detterman, R. L., 1961, Geology 

of the Shaviovik and Sagavanirktok Rivers region, Alaska: 

U.S. Geol. Survey Prof. Paper 303-D, p. 169-222, pls. 21-26. 

figs. 26-32. 

Lupher, R. L .. 1941, Jurassic stratigraphy of central Oregon: 

-Geol. Soc. America Bull., v. 52, no. 2. p. 219-269. 

1\Iarwick, .T olm, 1935. Some new genera of the Myalinidae and 

Pteriidae of Kew Zealand: Royal Soc. New Zealand Trans. 

and Proe., v. 63, p. 295-303, pls. 34-36. 
MESOZOIC PIDLECYPODS OTAPIRIA MARWICK AND LUPHERELLA. IMLAY Bll 

Marwick, John, 19'53, Divisions and faunas of the Hokonui System ('I1riassic and Jurassic) : New Zealand Geol. Survey 

Paleont. Bull. 21, 141 p., 17 pls. 

Muller, S. vV., 1938, Upper Triassic pelecypod genus JJionoUs: 

Geol. Soc. America Bull., v. 49, no. 12, p. 1893. 

Pchelintseva, G. T., 1955, Novye Autsellidy verkhnego Triasa i 

nizhnei Yury Dalnego Vostoka [New A.ucellidae of the 

Upper Triassic and the Lower Jurassic in the Far East], 

in Materialy po geologii i polznym iskopaemym, chast 2 : 

Vsesoyuznyi Geol. Inst., Materialy, new ser., no. 9, p. 211-

217, pls. 1-2. 

Tozer, E. T., 1961, Triassic stratigraphy and faunas, Queen 

Elizabeth Islands, Arctic Archipelago: Canada Geol. Survey 

Mem. 316, 116 p., 30 pls., 10 figs. 

Trechmann, C. T., 1923, The Jurassic rocks of New Zealand: 

Geol. Soc. London Quart. Jour., v. 79, pt. 3, p. 246-286, 

pls. 12-18. 

Vozin, V. F., and Tikhomirova, V. V., 1964, Polevoi atlas 

dvustvorchatykh i golovonogikh mollyuskov Triasovykh 

otlozhenii Severo-Vostoka SSSR [Field atlas of bivalved 

and cephalopod mollusks from the Triassic deposits from 

northeastern USSR] : Moscow, Izd-vo "Nauka," 195 p., 50 

pls., zonal table. 

'Vestermann, G. E. G., 1962, Succession and variation of JJionotis 

and the associated fauna in the Norian Pine River Bridge 

section, British Columbia (Triassic, Pelecypoda) : Jour. 

Paleontology, v. 36, no. 4, p. 745-792, pls. 112-118, 19 figs. 

Whitfield, R. P., 1885, Brachiopoda and Lamellibranchiata of 

the Raritan clays and greensand marls of New Jersey: 

U.S. Geol. Survey Mon. 9, 338 p., 35 pls. 

Zakharov, V. A., 1962, Novye Monotidae nizhnego Leiasa s 

poberezhya Okhotskogo Morya i ikh stratigraficheskoe 

znachenie [New Monotidae from the lower Lias of the 

Okhotsk Sea coast and their stratigraphic significance] : 

Geologiya i Geofizika, 1962, no. 3, p. 23-31, 3 illus. 

PLATES 1-2 
PLATE 1 

[Figures HI, 24 a nd 25 are natural si"e. All others are twice natural size] 

FIGURES 1- 23. Otapiria tailleuri (Imlay), n. sp. (p. B3). 

1. Paratype USNM 153272, left valve. 

2. Paratype USNM 153273, left valve. 

3. Paratype USNM 153274, left valve. 

4. Para type USNM 153275, left valve. 

5. Holotype USNM 153276, left valve. 

6. Para type USNM 153277, left valve and several small left and right valves. 

7. Paratype USNM 153278, left valve. 

8. Para type USNM 153279, left valve. 

9. Paratype USNM 153280, left valve. 

10. Para type USNM 153281, right v'alve showing byssal ear. 

11. Para type USNM 153282, right valve. 

12. Para.type USNM153283, right valve showing byssal ear. 

13. Paratype USNM 153284, right valve. 

14. Paratype USNM 153285, right valve. 

15. Para type USNM 153286, right valve showing interior. 

16. Paratype USNM 153287, right valve showing interior. 

17. Paratype USNM 15-3288, right valve. 

18. Paratype USNM 153289, right valve. 

19, 23. Para type USNM 153290, right V'alve (X 1 and X 2). 

20. Para type USNM 153291, right valve. 

21. Paratype USNM 153292, right valve. 

22. Para type USNM 153293, right valve. All specimens shown in figures 1- 9 arc from USGS Mesozoic loc. 

M2317. Those in figures 11, 13, 15, 17-22 are from USGS Mesozoic loc. M2317. Those in figures 10 

and 14 are from USGS Mesozoic loc. 24060. Those in figures 12 and 16 are from USGS ~lesozoic loc. 

M231S. All these specimens are from org'anic shale directly overlying Upper Triassic beds in 

northern Alaska. 

24, 25. Otapiria mars-halli (Trenchmann), (p. B1). 

24. Right valve, hypotype TM2390 from New Zealand Geological Survey loc. 348 on Otapiri Creek in 

Hokortui Hills, Kew Zealand. View made from plastet· replida. 

25. Left valve, hypotype TM2389 from New Zealand Geological Survey loc. 349 on Otapiri Creek in 

Hokonui Hills, New Zealand. View made from plaster replica. 
UEOLOGICAL SURVEY PROFESSIONAL PAPER 573-B PLATE 1 

4 5 

12 13 14 

10 

15 16 18 

19 

23 

OTAPIRIA 
PLATE 2 

[All figures arc twice natural size unless otherwise indicated] 

l<'IGURES 1-27. Lupherella boeohitormis (Hyatt), (P. B8). 

1. Syntype USNM 30189, left valve, view of rubber imprint. 

2. Lectotype USNM 153296, right valve. 

3-5. Cotypes USNM 30191 of "Daonella.'' ctM·dinoides Hyatt. l<'igure 3 is a left valve. Figures 4 and 5 

are right valves'. This species is a synonym of liu.phc1·clla bocchiformis (Hyatt). 

\3. Hypotype USNM 153297, left valve. Originally described as naonella sp. ( ?) by Hyatt (1894, p. 416). 

7. Hypotype USNM 153298, right valve (X 3). 

8. Hypotype USNM 153299, right valve (X 3). 

9. Hypotype USNM 153300, right valve (X 3). 

10. Hypotype USNM 153301, right valve (X 3). 

11. Hypotype USNM 153302, right valve (X 3). 

12. Hypotype USNM 153303, right valve (X 3). 

13. Hypotype USNM 153304, right valve. 

14. Hypotype Oalifornia Acad. Sci. 12778, right valve. 

15. Hypotype USNM 153305, right valve. 

16. Hypotype USNM 153306, right valve. 

17. Hypotype USNM 153307, right valve. 

18. Hypotype USNM 153308, right valve. 

19. Hypotype USNM 153309, right valve. 

20. Hypotype USNM 153~10, right valve. 

21. Hypotype USNM 153311, left valve. 

22. Hypotype USNM 153312, left valve. 

23. Hypotype USNM 153313, left valve. 

24. Hypotype USNM 153314, left valve. 

25. Hypotype USNM 153315, interior of right valve. 

26. Hypotype USNM 153316, left valve. 

27. Hypotype California Acad. Sci. 12779, right valve. All specimens shown on figures 1-6 are from the 

Sailor Canyon Formation at USGS Mesozoic loc. 2464, California. The specimens shown in figures 

7-13, 15-18, 20--24 and 26 are from the Nicely Formation of Lupher (1941) at USGS Mesozoic loc. 

29222, Oregon. Specimens shown in figures 14 and 27 ,are from the Kicely Formation at Lupher's 

loc. 125, Oregon. Figure W is from a rub!}er imprint of an external mold in brown mudstone of the 

Nicely }<'ormation at USGS Mesuzoic loc. 29326, Oregon. Figure 25 is from the Nicely Formation at 

USGS Mesozoic loc. 26740. Note anterior byssal ear shown in figures 7-12 and small anterior wing 

shown in figures 21-24 and 26. 

28--31. Otapi1·ia sp. undet. (p. B7). 

Figured specimens USNM 153295. l!'igures 28 and 29 are right valves showing byssal ear and notch. 

Figures 30, 31 are left valves'. All specimens shown in figures 28--31 from float at USGS Mesozoic Joe. 

M1717 in the upper Yukon Valley, Alaslra. 

32. Otapiria taillmtri Imlay, n. sp. (p. B3). 

Hypotype USNM 153294, from USGS Mesozoic loc. 24060, northern Alaska. Shows characteristic shape 

and rib!}ing of immature specimens. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 573-B PLATE 2 

2 

3 4 5 

3 

7 

6 8 

9 10 11 

12 

13 14 15 

17 18 

20 

21 22 23 

27 

28 

29 

LUPHERELLA, N. GEN. AND OTAPIRIA 

U.S, GOVERNMENT PRINTING OFFICE: 1967 0 - 237-493