Bull. Natl. Mus. Nat. Sci., Ser. A, 36(4), pp. 95–100, December 22, 2010

A New Earthworm Genus (Oligochaeta, Megadrili,
Megascolecidae) from Japan
Robert J. Blakemore1
1

Department of Zoology, National Museum of Nature and Science, 3–23–1
Hyakunin-cho, Shinjuku-ku, Tokyo, 169–0073 Japan
E-mail: rob.blakemore @ gmail.com(Received 8 September 2010; accepted 1 November 2010)

Abstract Genus Manus is newly proposed with type and only species Pheretima koellikeri
Michaelsen, 1928. Type specimens of the type species preserved in the Zoological Museum Hamburg
are inspected and sketched. Distribution of the species is Japan (Kyushu?) with an unconfirmed Korean record. The new genus is diagnosed by a secretory diverticulum opening adjacent to each prostate
gland and associated with a penial seta internally and, secondarily, on its manicate intestinal caeca.
Key words: Pheretima, new genus, Asiatic, prostates, conservation status, von Kölliker.

Introduction

Materials and Methods

Pheretimoids (Pheretima auct.) comprise atpresent 14 genera and 940 valid species fromca. 1,400 nominal taxa (Blakemore, 2004, 2007,2008a). The number of nominal taxa is nearly
double the 746 nominal species including subspecies when reviewed and divided into manageable taxonomic groups by Sims and Easton(1972) and is raised considerably from Michaelsen’s (1900a) list of just 167 valid Pheretima
species. They form a large and ecologically important group of Oriental earthworms with a few
peregrine members spread worldwide, especiallyin the tropics (see Blakemore, 2002, 2008b).
First emerging around 1903, Pheretima koellikeri Michaelsen, 1928 has had a varied taxonomic history, being sunk, elevated and transferred
between several genera—this indicative of its unusual characteristics that merit it separate genericstatus. Michaelsen (1928, p. 12) grouped it withJapanese Metaphire sieboldi (Horst, 1883) byvirtue of its manicate caeca, but also thought it
unique in Pheretima as then defined. This paper
aims to establish it firmly within bounds of ICZN(http://iczn.org/) stated aims for “standards, sense
and stability for animal names in science.”

Classification follows the conventions, methodology and abbreviations of Blakemore (2000,
2008b). Tissue samples from type specimens
were taken with the permission of the ZoologicalMuseum Hamburg (ZMH), and submitted to theInternational Barcode-of-Life program (iBOL
http://ibol.org/) for DNA sequencing which, if
successful for such old material, will have its
data entered into the BOLD database and to the
GenBank online facility [http://www.ncbi.nlm.
nih.gov/genbank/], as with samples in Blakemore
et al. (2010). Abbreviations used: lhs, left handside; rhs, right hand side.

Taxonomic results
Genus Manus Blakemore, nov.
Type and only species. Pheretima koellikeri
Michaelsen, 1928.
Distribution. Japan (Kyushu?) and possibly
Korea.
Diagnosis. Pheretimoid with secretory diverticulum opening adjacent to prostate gland on
non-superficial male pore with penial seta internally; intestinal caeca manicate from ca. 27.

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Robert J. Blakemore

Remarks. The genus has non-superficial
male pores that define both Metaphire Sims andEaston, 1972 and Pheretima Kinberg, 1867 but
it lacks the nephridia on the spermathecal duct
required for membership of the latter genus. Differentiation is via acquisition of pronounced secretory diverticula, rather then mere stalked
glands, opening along with pouched penes. The
relationship of Manus to Metaphire is analagous
to that of subgenus Parapheretima Cognetti,
1912 to Pheretima as exemplified by Pheretima(Parapheretima) saba Sims and Easton, 1972
when compared to Pheretima (Ph.) darnleiensis(Fletcher, 1886) in a detailed redescription in
Blakemore et al. (2007, figs. 2–6). Secretory diverticula resemble tubular prostates as found insome more ‘primitive’ members of Megascolecidae sensu Blakemore, 2000 (cf. Gates, 1959)
and in Acanthodrilidae but are presumed (byStephenson 1930, and the current author) to not
be homologous in these otherwise relatively “advanced” species.
Notwithstanding, Michaelsen (1928, p. 11)
doubting homology of these structures between
Pheretima koellikeri and Parapheretima because
they were more muscular in examples of the latter he had experience of, he also said “Das Auftreten von Penialborsten im Zusammenhang mit
diesen akzessorischen Prostaten der Pheretima
köllikeri, würde, falls es sich bestätigen liesse,meine Deutung dieser Organe als acanthodriline
Prostaten wesentlich stützen.” —[The occurrenceof penial setae in connection with this accessory‘prostate’ of Pheretima köllikeri would, if confirmed, support my interpretation of these organs
as much like acanthodriline prostates]. However,as Stephenson (1930) remarked, normal glandular prostates with the usual relations are also present, thus duplicated or transitional functionality
is unlikely. Unfortunately no complete specimens
are available to allow re-examination of the accessory gland and its true rôle can only be speculative: obviously relating to mutual exchange of
sperm when charging spermathecae, possibly it
facilitates adhesion of con-copulants (especiallysince the spermathecal pores have flat areolae),or it may serve in some way to prevent ingress ofpathogens and/or parasites.
Other Manus candidates are unknown despite
several Metaphire species having stalked glands,
rather than definite diverticula, on their copulatory pouches (when present) adjacent to non-superficial male pores.
Etymology. Manus—meaning“hand” in Latin(masculine gender)—listed neither in Airey
Neave’s Nomenclator Zoologicus (http://uio.mbl.
edu/NomenclatorZoologicus/) nor in the Thompson Reuter ION facility of names (http://www.organismnames.com/query.htm). This name alludes
to Röntgen’s famous X-ray picture of the hand of
Alfred von Kölliker who also had a ‘hand’ in thedetermination of Gregarine parasites and ofparthenogenesis in invertebrates, both pertinent
to earthworm studies. The name also references
the worm’s finger-like diverticular projections on
the fist-like copulatory pouches, as well as its
manicate caeca—these latter being a subordinatecharacteristic.

Manus koellikeri (Michaelsen, 1928), comb. nov.
(Figs. 1–2)
Pheretima sp. (Köllickeri Mich. Ms.) (sic, nomen nudum),
Michaelsen, 1903: 100.
Pheretima köllikeri Michaelsen, 1928: 8, figs. 1–2. [From“Japan” collected before 1903. Type specimens in the
Zoological Museum Hamburg (V6074).]
Pheretima kollikeri: Stephenson, 1930: 000.
Pheretima (Parapheretima) koellikeri: Sims and Easton,
1972: 240, 266; Easton, 1981: 60 (same as Pheretima
sp. Michaelsen, 1903, ?? P. vesiculata).
Metaphire vesiculata (part.): Blakemore, 2003: 1, 7, 31[with ? P. koellikeri as a provisional junior synonym ofprior P. vesiculata Goto and Hatai, 1899 (cf. Easton,1981) along with ? P. okutamaensis, ? P. biggiberosa];
Blakemore, 2004: 156.
? Metaphire koellikeri: Blakemore, 2007: 1, 20, 112,
125–6, fig. 6 (as provisional comb. nov. restoration separate from Perichaeta vesiculata Goto and Hatai,
1899); Blakemore et al., 2007: 36–37; Blakemore,
2010: 7.
Planapheretima koellikeri (sic, lapsus): Texas A & M
University website 2010 (http://insects.tamu.edu/research/collection/hallan/test/Annelida/Family/Megascolecidae.txt accessed 7. IX. 2010).

New Earthworm Genus from Japan

97

Fig. 1. Male organs (section of male pore) and a rhs spermatheca of Pheretima koellikeri after Michaelsen(1928, figs. 1–2).

Material examined. The type series (syntypes?) of ZMH V6074 with modern label stating: “Pheretima Köllikeri Type material”, comprising two specimens: one a posterior amputee
mature, previously dissected with most of internal organs removed such as gizzard, both lhs
spermathecae, and primary male organs except
for part of 18lhs prostate gland; thus, this is the
only known type, though it is not designated as
the lectotype. The second, longer, specimen waspreviously undissected but is immature, it wasdissected by the current author (RJB) for the firsttime to confirm its identity since the primary
type was so damaged. This latter specimen is a
probable syntype and thus eligible as a paralectotype. No other material is known to exist.
Origin of the type specimens. Although
Michaelsen attributed collection to “A. v.
Kölliker (Mus. München)” and wrote that thetypes belonged in the Zoological Museum Hamburg, they were transferred there from Munich(A. Schmidt-Rhaesa pers. comm. IX. 2010). It
may be reasonably surmised that their provision
is attributable to Rudolf Albert (or sometimes
Albrecht) von Kölliker (1817–1905), the contemporary Würzburg scientist and co-editor, alongwith members of the family von Siebold who hadstrong connections with Japan, of the journal
Zeitschrift für Wissenschaftliche Zoologie in
which Michaelsen often published. I can find noreport of A. von Kölliker visiting Japan, but hemay have been sent specimens via contacts with
von Siebold’s family. In which case, the type locality, as for some earlier von Siebold specimens,
may well be in Kyushu.
Distribution. “Japan.” Sims and Easton(1972, p. 221) mistakenly thought it an introduced Parapheretima and Easton’s (1981: 60)
distribution included Kyushu (from Kobayashi,
1941, p. 513), but his other records were for his
erroneous (priority) synonym (?? vesiculata Gotoand Hatai, 1899, p. 21). Kobayashi (1941) has an
unconfirmed report from Korea. Yasuaki Sugi
(pers. comm. 2. IX. 2010) did have records
thought to be P. koellikeri from Kyushu, although
he says these are P. vesiculata, rather than P. koellikeri proper.
Conservation status. This species appears tohave been recorded only once by Kobayashi(1941) since its original description in 1903.
Thus its status may be classed as rare or uncertain in both Japan and Korea.
External characters. Colour grey with clitellum buff in alcohol (based on type specimens).
Body has much secondary annulation. Length
148–164 mm by 8–9 mm with 100 segments(Michaelsen, 1903) [the first specimen explainedin “Material examined” (current candidate for‘lectotype’) 150 with 80 segments and thesecond specimen (immature, candidate for ‘paralectotype’) 170 mm with 140 segments, i.e.,agreeing tolerably]. Setae 37–57. First dorsal

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Robert J. Blakemore

Fig. 2. The first specimen of type series of Manus koellikeri (Michaelsen, 1928), comb. nov. (Zoological Museum Hamburg V6074) with enlargement of 8 rhs spermatheca; boxed sketch: lhs spermathecae, 18 rhs prostateand manicate caecum of the immature second type specimen of V6074.

New Earthworm Genus from Japan

pore 12/13 (with that in 11/12 minute and pokedby Michaelsen in ‘lectotype’). Male pore ca. 0.3
circumference apart on penes invaginated within
gaping transverse slots on large “ill-defined”
porophores on 18 that extend across intersegmental furrows into 17 and 19; a dozen setae intervene (Michaelsen). Female pore single, ventromedian on 14. Spermathecal pores in 6/7/8 ca.
0.4 C apart. Genital markings absent except forpads around spermathecal pores noted for the
first time (pers. obs. and current Fig. 2).
Internal morphology. Only part of oesophagus in 13 with ovaries and last hearts plus an anterior pair of pseudovesicles remain in the ‘lectotype’ with prostates just a glandular part on
18rhs, thus account mostly from Michaelsen’s
original. Septa 7/8 weak, 8/9/10 absent (fromboth type specimens), 10/11 thin, 11/12–14/15
thickened, thereafter thin. Gizzard strong barrelshaped. Holandric with testis sacs ventral in 10
and 11; seminal vesicles anteriorly in 11 and 12,
the later pair with more distinct appendices.
Pseudovesicles anteriorly in 13 noted for the
first time. Prostates racemose in 17–22 each
ducting to penis within copulatory pouch that isconfined to body wall with accessory secretory
diverticulum opening anterior to male pore andassociated with a large penial seta (as shown in
Michaelsen’s fig. 1). These diverticula resemble
flattened tubular prostates and extend to segments 16 or 17. Spermatheca with diverticulum
shorter than ampulla and Michaelsen shows one
with zig-zagging diverticular bulb; in contrast,
the current ‘lectotype’ had flat, rather compact
bulbs on short only slightly wavy stalks (Fig. 2).
Both diverticula stalk and spermathecal duct aremuscular and no nephridia are attached (pers.
obs. and Michaelsen, fig. 2). Intestinal caeca
manicate (confirmation) and gut contains yellow
soil and coarse organic matter in type; typhlosole
not found.
Remarks. The accessory secretory diverticula are characteristic. Each with this form (translated from Michaelsen’s German): “A large,
broad tongue-shaped gland extends from thepenis apparatus towards the front as far as seg-99

ment 17 or 16, with its ental part bent to the sideand backwards. This gland is almost flat, superficially notched only weakly, but with a very delicately cracked network, having the appearance ofthe prostatic glands of some other species of
Pheretima, but much more compact. The axial
canal is lined with columnar epithelial cells,
whereas small groups of gland cells form thebulk of the gland.”Michaelsen compares this accessory structure
to that in Cognetti’s Parapheretima, probably
leading Sims and Easton (1972, p. 266) to liken
their Ph. (Paraph.) saba with Ph. (Paraph.) koellikeri although lack of nephridia on its spermathecal ducts clearly disqualifies it from the genus
Pheretima s. stricto.
Easton’s improper synonymy of prior Metaphire
vesiculata under Pheretima koellikeri presumably
assumed this species had nephridia on its spermathecal ducts (although Michaelsen’s fig. 2
shows none, and their lack is confirmed from typespecimens), and that M. vesiculata had them too(plus secretory glands?). Goto and Hatai (1899,
fig. 15) did not describe any such glands for theirP. vesiculata and, moreover, a usual characteristicof Metaphire is having stalked glands, rather thansecretory diverticula, on the copulatory pouches(Sims and Easton, 1972, pp. 215, 221; Blakemore,
2008a).
Sims and Easton (1972, p. 222) had only provisionally placed koellikeri in the subgenus
Pheretima (Parapheretima) because Michaelsen(1928, p. 11) remarked on its similarity to othercongeners. During provisional placement of koellikeri in Metaphire by Blakemore (2007, p. 126)
it was noted that it might merit allocation to another, possibly new, genus on the basis of its secretory diverticula. This action is taken here.
Augmentation from Michaelsen’s original description (and Easton’s that included M. vesiculata in part) are that the current type has large flat
pads around the spermathecal pores, possibly
these have some corollary function to the diverticula and penial setae of the male pores. Moreover, the spermathecal diverticula differ slightly
from Michaelsen’s account as the muscular stalks

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Robert J. Blakemore

are not quite as short and the bulb not as zigzagged as shown in his (or an artist’s impression)
figure.
Previously thought to resemble parts of the M.
hilgendorfi species-group (Blakemore 2003,
2010), it is now clearly separated. Further study
is needed to relocate Manus koellikeri in its placeof origin—possibly in Kyushu—to determine its
conservation status, and, if it still survives, to investigate its natural habitat and ecological associations.
Etymology. Emendation of latinized SwissGerman honourific partronym; sometimes misspelt “kollikeri.”Acknowledgements
This study was facilitated under logistic and financial offset support of the National Museum of
Nature and Science, Tokyo under the kind auspices of Dr. Toshiaki Kuramochi. Curator in
Biozentrum Grindel/Zoological Museum Hamburg, Dr. Andreas Schmidt-Rhaesa, is thanked
for providing loan of type specimens and for his
generous help accessing Michaelsen’s earlier
publications.
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