A new species of Admete (Gastropoda: Cancellariidae: Admetinae) from the Paleocene of eastern Hokkaido, northern Japan

Abstract

A new cancellariid species, Admete katsuhiraensis new species is
described from the Paleocene Katsuhira Formation in Urahoro
Town, eastern Hokkaido, Japan. This is the oldest record of
cancellariid gastropods in Japan and also the oldest record of
the genus Admete and the subfamily Admetinae worldwide.
Although the known fossil record of the genus is very incomplete,
occurrence of Paleocene Admetinae in deep sea deposits
of the Katsuhira Formation in northern Japan provides an
interesting insight into the timing of origin of the present day
cold water molluscan fauna in the northern Hemisphere.

Full text

A new species of Admete (Gastropoda: Cancellariidae: Admetinae)
from the Paleocene of eastern Hokkaido, northern Japan
Kazutaka Amano
Department of Geoscience
Joetsu University of Education
1 Yamayashiki
Joetsu 943-8512, JAPAN
Anton Oleinik
Department of Geosciences
Florida Atlantic University
777 Glades Road
Boca Raton, FL 33431 USA
Robert G. Jenkins
School of Natural System
College of Science and Engineering
Kanazawa University
Kanazawa City, Ishikawa 920-1192, JAPAN
ABSTRACT
A new cancellariid species, Admete katsuhiraensis new species is
described from the Paleocene Katsuhira Formation in Urahoro
Town, eastern Hokkaido, Japan. This is the oldest record of
cancellariid gastropods in Japan and also the oldest record of
the genus Admete and the subfamily Admetinae worldwide.
Although the known fossil record of the genus is very incom-
plete, occurrence of Paleocene Admetinae in deep sea deposits
of the Katsuhira Formation in northern Japan provides an
interesting insight into the timing of origin of the present day
cold water molluscan fauna in the northern Hemisphere.
INTRODUCTION
Cancellariids consist of a diverse group of mostly warm-
water mollusks. Biodiversity estimates for Cancellariidae
include 1200 fossil and 300 recent species (Hemmen,
2007), and 124 genera and 1864 recent and fossil species,
according to Petit and Harasewych (2005). The oldest
geological records of the family date from the Late Cre-
taceous (Cenomanian) of Texas and the family reached
its maximum diversity in the Eocene and Miocene
(Stephensen, 1952; Taylor and Morris, 1988; Hemmen,
2007). No Cretaceous cancellariids have been recorded
from Japan (see Hayami and Kase, 1977; Kase, 2001).
The oldest species from Japan are Cancellaria? sp. indet.
a, b, c, d from the upper Eocene Kyuragi and Kijima
Formations and the lower Oligocene Yamaga Formation
in northern Kyushu (Nagao, 1928). However, columellar
folding, one of the distinct characteristics of cancellariids,
has not been recognized on those Eocene species from
Kyushu. These Paleogene species from Kyushu were
reexamined by Oyama et al. (1960), and C.? sp. indet. a,
b from the upper Oligocene Yamaga Formation were
reassigned to Trigonostoma?(Scalptia?) sp. No Paleo-
gene cancellariids have been recorded in Sakhalin, while
several cancellariid species have been described and
illustrated from the Paleogene deposits of western
Kamchatka (Gladenkov et al., 1991).
Specimens of a small cancellariid have been recently
collected from the Paleocene (Danian–Selandian)
Katsuhira Formation (see Amano and Jenkins, 2014) in
eastern Hokkaido. In this paper, we describe these as a
new species and discuss its biogeographic significance.
MATERIALS AND METHODS
Two specimens of cancellariid gastropods were collected
from dark gray mudstone of the upper part of Katsuhira
Formationat the cliff along Urahoro River near Katsuhira,
Urahoro Town, eastern Hokkaido (Figure 1). The age of
the formation was assigned to the Paleocene (Danian–
Selandian), based on the planktonic foraminifera and
calcareous nannofossils (Kiminami et al., 1978; Kaiho,
1984; see also Amano and Jenkins, 2014).
Cancellariid specimens from this locality are associated
with protobranch bivalves such as Acila,Leionucula,
Malletia, and deep-sea arcid Bentharca steffeni Amano,
Jenkins and Nishida, 2015. Although paleoenvironments
of the Katsuhira Formation have not been studied
in detail, these bivalves indicate deposition in deep
water (Amano and Jenkins, 2014; Amano and Oleinik,
2014; Amano et al., 2015). One institutional acronym
used is: JUE, Joetsu University of Education, Joetsu,
Niigata Prefecture.
SYSTEMATIC PALEONTOLOGY
Class Gastropoda Cuvier, 1797
Order Neogastropoda Wenz, 1938
Superfamily Cancellarioidea Forbes and Hanley, 1851
Family Cancellariidae Forbes and Hanley, 1851
Subfamily Admetinae Troschel, 1865
Remarks: Admetinae is characterized by thin shell
and columella with arched and weak columellar folds
(Wilson, 1994). Recent molecular phylogeny work
reveals that this subfamily, as it is now understood, is
polyphyletic (Modica et al., 2011). The genus Admetula
THE NAUTILUS 130(3):116–121, 2016 Page 116

Cossmann, 1899 is considered as a separate from
Admetinae clade. This classification was used by
Harzhauser and Landau (2012) when they revised the
Neogene cancellariids of the Paratethys. They also
treated Bonellitia Jousseaume, 1887 as the Admetula
clade, despite of lack of molecular data.
Genus Admete Krøyer in Mo
¨ller, 1842
Type Species: Admete crispa Mo
¨ller, 1842 (¼Tritonium
viridulum Fabricius, 1780) by monotypy.
Remarks: The genus Admete is characterized by a
rather thin shell with large last whorl, deep sutural
groove, narrow shoulder and by having a straight
collumella with two weak folds and narrow umbilicus
or slit (Harasewych and Petit, 1986: 86; this study).
Neadmete Habe, 1961 can be separated from the genus
Admete by having a higher spire and rather straight
collumella with three folds. Zeadmete Finlay, 1926 dif-
fers from Admete by a fine cancellate sculpture on entire
surface. Genera Admetula and Bonellitia have a thick
crenulated outer lip, three strong columellar folds and
lack umbilicus or slit. The American Cretaceous genus
Admetopsis Meek, 1873 including Admete?gregaria
Meek, 1873, A.? subfusiformis and A.? rhomboides Meek,
1873 can be clearly separated from Admete by having
rounded whorls without shoulder, a significantly higher
spire, an anteriorly thickened calcareous callus, by
weaker or absent of collumellar folds, and lack of an
umbilicus or slit. It is presently not clear if Admetopsis
belongs to Admetinae or not. Another American Creta-
ceous genus Paladmete Gardner, 1916 can be easily dis-
tinguished from Admete by having a smooth collumella
without folds. Stephenson (1941) established family
Paladmetidae based on this genus.
Admete katsuhiraensis new species
(Japanese vernacular name: Katsuhira-koromogai)
(Figures 2, 3)
Diagnosis: Shell small with cancellate sculpture
consisting of 15 to 21 spiral cords and 19 to 23 axial ribs.
Figure 1. Locality map of Admete katsuhiraensis new species. (Base map is from “Katsuhira”, scale 1: 25,000; topographical map
published by the Geospatial Information Authority of Japan).
K. Amano et al., 2016 Page 117

Four whorls with rather deep sutural groove; spire low,
1/8 of shell height. Columella nearly straight with two
weak folds; inner lip broadly covered by thin calcareous
callus; siphonal canal short with very weak fasciole and
very narrow umbilical slit.
Description: Shell small, attaining 11.4 mm in height,
thin, fusiform, with four whorls. Sutural groove rather
deep; very narrow shoulder present in holotype. Last
whorl large, occupying approximately 7/8 of the height
of shell; spire very low; protoconch poorly preserved,
half of smooth volution remaining. Surface of last whorl
sculptured by 19 to 23 rounded axial ribs that become
obsolete toward base, separated by equal or narrower
interspaces, more distinct near suture. Spiral sculpture
of last whorl consisting of 15 to 21 flat cords sometimes
with one weak cord in between. Sculpture of penulti-
mate whorl consisting of 20 fine axial ribs and five spiral
cords in holotype. Outer lip thin and not crenulated;
columella nearly straight with two weak folds; inner lip
broadly covered by thin calcareous callus; siphonal canal
short with very weak fasciole and very narrow umbilical
slit recognized in paratype specimen.
Type Material: Holotype, JUE no. 15939 (Shell
height, 8.0 mm; Diameter, 6.0 mm); Paratype, JUE
no. 15940 (Shell height, 11.4 mm; Diameter, 9.9 mm)
Type Locality: The cliff along Urahoro River at 750 m
downstream from the mouth of Katsuhirazawa River,
Urahoro Town, eastern Hokkaido. Danian to Selandian
Katsuhira Formation.
Remarks: Admete viridula (Fabricius, 1780) is the only
species of Admete recorded from the upper Miocene to
Pleistocene deposits in Japan as A. couthouyi (Jay, 1839)
(Amano, 1983; Baba, 1990). According to Sneli and
Stockland (1986), the latter name is a junior synonym of
A. viridula. This species differs from A. katsuhiraensis
new species by its larger size (more than 20 mm in
height), a rounded shoulder, very faint columellar plaits
andmorestronglycurvedcolumella.
Admete katsuhiraensis new species is similar to
Admete profundicola (Okutani, 1964) which lives at
1500 m depth off Sagami Bay, central Honshu. Both
species share small shell size (A. profundicola; shell
height, 7.8 mm; diameter, 5.0 mm), angulated shoulder,
Figures 2, 3. Admete katsuhiraensis new species. 2. Paratype, JUE no. 15940; 2a, adapertural view; 2b, apical view; 2c, apertural
view. 3. Holotype, JUE no. 15939; 3a, apical view, 3b, adapertural view; 3c, apertural view.
Page 118 THE NAUTILUS, Vol. 130, No. 3

very narrow umbilicus, two columellar folds and similar
number of spiral cords (15 in the last whorl of
A. profundicola). The new species is different from
A. profundicola in having a lower spire and more numer-
ous axial ribs (17–19 in the last whorl of A. profundicola).
The new species resembles A. californica Dall, 1908
(found around 1103 meters in the Gulf of California) by
having a similar number of spiral cords and axial ribs
(both 20 in the last whorl of A. californica). However,
the new species can be separated from A. californica by
having a larger shell (16 mm in height of A. californica),
lower spire and very narrow umbilical split.
The new species differs from the Miocene
A. kamtschatica Sinelnikova in Gladenkov and Sinelnikova,
1990 from the Ilyinskaya Formation, western Kamchatka
by its smaller size, more compressed shell, with less
whorls, a more inflated and larger (7/8 of the total shell
height) last whorl, and a deep sutural groove.
Cancellaria globulosa Holzapfel, 1888, from the
Cretaceous of western Germany, has a similar outline of
shell and two columellar folds. However, it differs from
the new species by its thick shell with multiple crenula-
tions inside the outer lip, lack of a deep suture, and lack
of an umbilical slit.
Etymology: The new species is named for the location
where the type material was collected.
Distribution: Known only from the type locality,
Paleocene Katsuhira Formation, Danian to Selandian,
Urahoro Town, eastern Hokkaido.
DISCUSSION
The oldest fossil specimens identified as Admete? were
recorded from the Cretaceous in North America. How-
ever, as noted above, these species belong to a distinct
genus, Admetopsis.Admete (Bonellitia)funigera described
by Staadt in Cossmann, 1913 (202–203, pl. 7, figs 212–9),
from the Paleocene of France, possesses strong collumella
folds, and lack a sutural groove and umbilical slit. These
morphologic features suggest that A. funigera should be
classified as Bonellitia as was originally proposed by the
author. Kollmann and Peel (1983: 93, fig. 209) described
and figured an Admete from the Paleocene (Selandian)
Sonja Member of the Agatdal Formation in central
Nu
ˆgssuaq of western Greenland. Schnetler and Petit
(2010: 22) reexamined these gastropods and allocated that
species to Eocantharus Clark, 1938 (family Buccinidae).
One more species of Admete was recorded from the
Paleocene (early Selandian) of Greensand at Sundkrogen,
Copenhagen, Denmark. The following species from these
deposits were described as Cancellaria by von Koenen
(1885: 8–12): C. latesulcata, C. conoidea, C. tricarinata,
and C. curta; Ravn (1939) placed them in “Admete?.”
However, the former three species were later allocated
respectively to Admetula, Kroisbachia and Brocchinia by
Schnetler (2001). Although that author eliminated the
question mark from A.?curta, it is difficult to decide
whether to allocate it to Admete because of its very small
shell size (3.7 mm; Ravn, 1939: 86, pl. 3, figs 20a, b) and
relatively large protoconch, indicative of a juvenile indi-
vidual. The genera Kroisbachia,Brocchinia,Admetula,
and Unitas are known from the lower Paleocene
(Luzanovka beds) of Ukraine (Makarenko, 1976).
Bonellitia (Admetula)paucivaricata (Gabb, 1864) was
illustrated from the Paleocene (Danian) Getkilninskaya
Formation by Gladenkov et al. (1997: pl. 33, fig. 33).
Admete ornata Ilyina, 1955 was described from the
Paleogene of the Ustiurt region (vicinity of the Aral Sea)
(Ilyina, 1955: 78, pl. 30, fig. 16). However, that species
has strong axial ribs and lack sutural groove which is not
characteristic of the genus Admete. Although the family
Cancellariidae is present in the Paleocene deposits of
Europe, Greenland and Kamchatka, no proven records
of the subfamily Admetinae are known to date from
Paleogene deposits anywhere in the world. Thus, Admete
katsuhiraensis new species from the Danian to Selandian
Katsuhira Formation is not only the oldest record of
cancellariid in Japan, but also constitutes the oldest record
of the genus Admete and the subfamily Admetinae.
The genus Admete Kryer in Mo
¨ller, 1842, today is
restricted to cold waters and considered to be an Arcto-
Boreal taxon (Kantor and Sysoev, 2006; Thorson, 1944;
Macpherson, 1971; Golikov and Scarlato, 1977; Golikov,
1995; Golikov and Sirenko, 1998, 2004; Gulbin, 2004).
Occurrences of the genus Admete in the Southern Hemi-
sphere and subantarctic waters (Powell, 1951, 1958;
Knudsen, 1964) have yet to be investigated. Some of these
have been already reassigned to different genera, the tax-
onomic status of other species have to be adjusted after
the study of soft parts morphology. Arctic and Antarctic
mollusks are well known for the convergence in shell
morphology, which makes their identification based on
the shell morphology alone uncertain at best.
Paleocene marine isotopic records do not indicate a
significant departure in sea-surface temperature values
from the Late Cretaceous and do not indicate the exis-
tence of a significant thermocline (Bralower et al., 2002;
Dutton et al., 2005), but there are some indications of
warm global temperatures (Adatte et al., 2002) during
the early Paleocene. These paleoceanographic condi-
tions, coupled with continuous extended shallow shelf
around the rim of the North Pacific, facilitated the dis-
persal of molluscan faunas, which resulted in general
similarity between the northeastern and northwestern
Pacific Paleocene molluscan faunas. The majority of
faunas appears to be of warm to warm-temperate affini-
ties (Oleinik, 2001), lacking cold-water taxa found in the
North Pacific today. Fauna of the Katsuhira Formation,
which was previously virtually unknown, shows a depar-
ture from this general pattern in having a very high degree
of endemism and the appearance of new genera, such as
the buccinid Urahorosphaera (Amano and Oleinik, 2014),
new species such as the aporrhaid, Kangillioptera inouei
(Amano and Jenkins, 2014), or the first appearance of the
modern day cold water genus Admete described herein.
Since there are no true Paleocene Admete species or even
K. Amano et al., 2016 Page 119

subfamily Admetinae records anywhere in the northern
hemisphere, the occurrence of Admete katsuhiraensis
new species has interesting implications on the history of
the formation of cold water molluscan faunas known today
in the Arctic and boreal regions.As noted above, the lithol-
ogy and faunal assemblage of the Katsuhira Formation,
from which Admete katsuhiraensis new species was found,
are indicative of relatively deep water deposits. That not
only makes this locality unique among the North Pacific
shallow-marine Paleocene deposits, but also may suggest a
deep water origin of some modern day Arcto-Boreal taxa
in the early part of the Paleogene in the North Pacific.
ACKNOWLEDGMENTS
This study was partly supported by a Grant-in-aid for
Scientific Research from the Japan Society for Promotion
of Science (C, 26400500, 2014–2016) to KA and RGJ.
LITERATURE CITED
Adatte, T., G. Keller, and W. Stinnesbeck. 2002. Late Cretaceous
to early Paleocene climate and sea-level fluctuations: the
Tunisian record. Palaeogeography, Palaeoclimatology,
Palaeoecology 178: 165196.
Amano, K. 1983. Paleontological study of the Miocene Togeshita
molluscan fauna in the Rumoi district, Hokkaido. Science
Report of the Institute of Geoscience, University of
Tsukuba, Section B 4: 1–72.
Amano, K. and R.G. Jenkins. 2014. A new Paleocene species of
Aporrhaidae (Gastropoda) from eastern Hokkaido, Japan.
Paleontological Research 18: 33–39.
Amano, K., R.G. Jenkins, and K. Nishida. 2015. A new Paleo-
cene species of Bentharca (Bivalvia; Arcidae) from eastern
Hokkaido, with remarks on evolutionary adaptation of sus-
pension feeders to the deep Sea. Paleontological Research
19: 128–138.
Amano, K. and A. Oleinik. 2014. A new genus of Buccinoidea
(Gastropoda) from Paleocene deposit in eastern Hokkaido,
Japan. The Nautilus 128: 122–128.
Baba, K. 1990. Molluscan Fossil Assemblages of the Kazusa
Group, South Kanto, Central Japan. Keio Gijuku Yochisha,
Tok yo, 445 pp. (In J ap an es e)
Bralower, T.J., I. Premoli-Silva, and M.J. Malone. 2002. New
evidence for abrupt climate change in the Cretaceous and
Paleogene: An ocean drilling program expedition to Shatsky
Rise, northwest Pacific. GSA Today 12: 4–10.
Clark, B.L. 1938. Fauna from the Markley Formation (Upper
Eocene) on Pleasant Creek, California. Bulletin of the
Geological Society of America 49: 683–730.
Cossmann, A.M. 1899. Essais de Pale
´oconchologie Compare
´e.
Volume 3. Published by the author and Comptoir
Ge
´ologique, Paris, 201 pp.
Cossmann, M. 1913. Catalogue illustre
´des coquilles fossiles de
l’E
´oce
`ne des environs de Paris. Appendice No. 5. Annales
de la Socie
´te
´Royale Zoologique et Malacologique de
Belgique 49: 19–238.
Dall, W.H. 1908. Reports on the dredging operations off the
west coast of Central America to the Galapagos, to the
west coast of Mexico, and in the Gulf of California, in
charge of Alexander Agassiz, carried by the in the U. S.
Fish Commission steamer “Albatross”, from October 1904
to March 1905, Lieut. Commander L. M. Garrett, U. S. N.
commanding. XIV. The Mollusca and Brachiopoda. Bulletin
of the Museum of Comparative Zoology 43: 205–487.
Dutton, A., K.C. Lohmann and R.M. Leckie. 2005. Insights
from the Paleogene tropical Pacific: Foraminiferal stable
isotope and elemental results from site 1209, Shatsky Rise.
Paleoceanography 20, PA3004, doi: 10.1029/2004, PA001098.
Fabricius, O. 1780. Fauna Groenlandica. Hafnia et Lipsiae,
452 pp.
Finlay, H.J. 1926. A further commentary on New Zealand
molluscan systematics. Transactions of the New Zealand
Institute 57: 320–485.
Forbes, E. and S., Hanley. 1851. A history of British Mollusca and
their shells. Vol. III. Including the families of Gasteropoda
from Neritidae to Elysiadae. Van Voorst, London, 616 pp.
Gabb, W. M., 1864. Description of the Cretaceous fauna.
California Geological Survey, Palaeontology of California
1, 57–243.
Gardner, J.A. 1916. Systematic paleontology, Mollusca,
pp. 371–733, pls. 12–45. In: Maryland Geological Survey,
Upper Cretaceous. Johns Hopkins Press, Baltimore. 1022 pp.
Gladenkov, Yu. B, A. E., Shantser, A. I., Chelebaeva, et. al. 1997.
The Lower Paleogene of Western Kamchatka (stratigraphy,
paleogeography, geologic events). Transactions of the
Russian Academy of Sciences Geological Institute, Vol 488:
367 pp. (in Russian)
Gladenkov, Yu.B., V.N. Sinelnikova, A.E. Shantser, A.I.
Chelebaeva, A.E. Oleinik, L. V. Titova, G.M. Bratseva,
N.A. Fregatova, E.V. Ziryanov, and K.G. Kazakov. 1991.
The Eocene of western Kamchatka. Transactions of the
Geological Institute, Academy of Sciences of the USSR
467: 1–182. (in Russian)
Gladenkov, Yu.B. and V.N. Sinelnikova, 1990. Miocene Mol-
lusks and Climatic Optimums in Kamchatka. Transactions
of the Russian Academy of Sciences Geological Institute,
Nauka Publisher, Vol 453, 371 pp. (in Russian)
Golikov, A.N. 1995. Shell-bearing gastropods of the Arctic.
Colus, Moscow, 108 pp.
Golikov, A.N. and O.A. Scarlato. 1977. Composition, distribution
and ecology of gastropod and bivalve mollusks off Franz
Josef Land. In: A. N. Golikov (ed.) Biocoenoses of the shelf
of Franz Joseph Land and the fauna of adjacent waters.
Issledovaniya Fauny Morei, 14(22): 313–390. (in Russian)
Golikov, A.N. and B.I. Sirenko. 1998. Prosobranch gastropods
of the continental slope of the Kurile Islands. Ruthenica
8: 1–45.
Golikov, A.N. and B.I. Sirenko. 2004. Class Gastropoda, sub-
class Cyclobranchia, subclass Scutibranchia, subclass
Pectinibranchia, subclass Sinistrobranchia. In: Fauna and
ecosystems of the Laptev Sea and adjacent deep waters
of the Arctic Basin. Issledovaniya Fauny Morei 54(62),
pt. 2, pp. 145–147. (in Russian)
Gulbin, V.V. 2004. Fauna of prosobranch gastropods of
Peter the Great Bay, Sea of Japan, and the biogeographical
composition. Russian Journal of Marine Biology 30(1):
1–10. (in Russian)
Habe, T. 1961. Coloured illustrations of the shells of Japan (II).
Hoikusha, Osaka. 182 pp. Appendix 42 pp. (in Japanese)
Harasewych, M.G. and R. E. Petit. 1986. Notes on the mor-
phology of Admete viridula (Gastropoda, Cancellariidae).
The Nautilus 100: 85–91.
Harzhauser M. and B. Landau. 2012. A revision of the
Neogene cancellariid gastropods of the Paratethys Sea.
Zootaxa 3472: 1–71.
Page 120 THE NAUTILUS, Vol. 130, No. 3

Hayami, I. and T. Kase. 1977. A systematic survey of the Paleo-
zoic and Mesozoic Gastropoda and Paleozoic Bivalvia
from Japan. University of Tokyo Press, Tokyo, 132 pp.
Hemmen, J. 2007. Annotated and illustrated catalogue of
Recent Cancellariidae. Jens Hemmen, Wiesbaden, 428 pp.
Holzapfel, E. 1888. Die Mollusken der Aachener Kreide.
Palaeontographica 34: 29–180.
Ilyina, A.P. 1955. Mollusks of the Paleogene of northern Ustyurt.
Proceedings of the Petroleum Research and Geological
Exploration Institute of the Soviet Union, new series,
89: 1–90. (in Russian)
Jay, J.C. 1839. A catalogue of the shells, arranged according to
the Lamarckian system; together with descriptions of new
or rare species, contained in the collection of John C. Jay,
M.D., 3
rd
edition. Wiley and Putnam, New York, 125 pp.
Jousseaume, F. P. 1887. La famille des Cancellariidae
(Mollusques gaste
´ropodes). Le Naturaliste, 9, 2e Se
´rie:
155–157, 192–194, 213–214, 221–223.
Kaiho, K. 1984. Foraminifera biostratigraphy from the upper
Cretaceous and Paleogene in Shiranuka Hill district, eastern
Hokkaido. In: Saito, T., Okada, H. and Kaiho, K. eds.,
Biostratigraphy and International Correlation of the Paleo-
gene System in Japan: 35–50. Faculty of Science, Yamagata
University, Yamagata. (In Japanese; original title translated)
Kantor, Yu. I. and A.V. Sysoev. 2006. Marine and brackish
water Gastropoda of Russia and adjacent countries: an
illustrated catalogue. KMK Scientific Press Ltd., 371 pp.
140 pl.
Kase, T. 2001. Paleozoic and Mesozoic Gastropoda,
Monoplacophora and Hyolitha. In: Ileya, N., Hirano, H.
and Ogasawara, K. eds. The database of Japanese fossil type
specimens described during the 20
th
Century. Paleonto-
logical Society of Japan, Special Papers 39: 374–395.
Kiminami, K., K. Takahashi, and K. Maniwa. 1978. The Creta-
ceous system in Hokkaido–Yezo and Nemuro groups. Mono-
graph of the Association for the Geological Collaboration
in Japan 21: 111–126. (In Japanese with English abstract)
Knudsen, J. 1964. Scaphopoda and Gastropoda from depths
exceeding 6000 meters. Galathea Report 7: 125–136.
Kollmann, H.A. and J.S., Peel. 1983. Paleocene gastropods
from Nu
ˆgssuaq, West Greenland. Grnlands Geologiske
Undersgelse Bulletin 146: 1–115.
Macpherson, E. 1971. The Marine Mollusks of Arctic Canada.
Prosobranch Gastropods, Chitons, and Scaphopoda.
National Museum of Natural Sciences Publications in
Biological Oceanography 3, 149 pp. Ottawa.
Makarenko, D.E. 1976. Paleocene gastropods of the northern
Ukraine. Naukova Dumka, Kiev, 179 pp, 18 pl. (in Russian)
Meek, F.B. 1873. Preliminary paleontological report, consisting
of lists and descriptions of fossils, with remarks on the ages
of the rocks in which they were found. United States
Geological Survey of the Territories, Sixth Annual Report,
429–518.
Modica, M.V., P. Bouchet, C. Cruaud, J. Utge, and M. Oliverio.
2011. Molecular phylogeny of the nutmeg shells
(Neogastropoda, Cancellariidae). Molecular Phylogenetics
and Evolution 59: 685–697.
Mo
¨ller, H.P.C. 1842. Index Molluscorum Groenlandiae.
Naturhistorisk Tidsskrift 4: 76–97.
Nagao, T. 1928. A summary of the Paleogene stratigraphy of
Kyushu, Japan, with some accounts on the fossiliferous
zones. Science Reports of the Tohoku Imperial University,
Second Series 12: 1–140.
Okutani, T. 1964. Report on the archibenthal and abyssal
gastropod Mollusca mainly collected from Sagami Bay
and adjacent waters by the R. V. SOYO-MARU during
the years 1955–1963. Journal of the Faculty of Science,
University of Tokyo, Section II 15: 371–447.
Oleinik, A.E. 2001. Eocene gastropods of western Kamchatka —
implications for high-latitude north Pacific biostratigraphy
and biogeography. Palaeogeography, Palaeoclimatology,
Palaeoecology 166: 121140.
Oyama, K., A., Mizuno, and T. Sakamoto. 1960. Illustrated
handbook of Japanese Paleogene mollusks. Geological
Survey of Japan, Kawasaki, 244 pp.
Petit, R.E. and M.G. Harasewych. 2005. Catalogue of the super-
family Cancellarioidea Forbes and Hanley, 1851 (Gastropoda:
Prosobranchia)—2nd edition. Zootaxa 1102: 1–161.
Powell, A.W.B. 1951. Antarctic and Subantarctic Mollusca:
Pelecypoda and Gastropoda. Discovery Reports 26: 47–196.
Powell, A.W.B. 1958. Mollusca from the Victoria-Ross Quad-
rants of Antarctica. Reports of B.A.N.Z. Antarctic Research
Expedition 1929–31, Series B, 6(9): 167–214.
Ravn, J.P.J. 1939. E
´tudes sur les mollusques du Pale
´oce
`ne
de Copenhague. Biologiske Skrifter (Kongelige Danske
Videnskabernes Selskab) 1: 1–106.
Schnetler, K. I. 2001. The Selandian (Paleocene) mollusk fauna
from Copenhagen, Denmark: the Poul Harder 1920 col-
lection. Geology of Denmark Survey Bulletin 37: 1–85.
Schnetler, K.I. and R.E. Petit. 2010. Revision of the gastropod
family Cancellariidae from the Paleocene Nuussuaq, West
Greenland. Cainozoic Research 7: 3–26.
Sneli, J.-A. and O
¨. Stockland. 1986. On the taxonomical status
of Tritonium viridulum Fabricius, 1780 (Gastropoda:
Cancellariidae). The Nautilus 100: 121–124.
Stephenson, L.W. 1941. The larger invertebrate fossils of the
Navarro Group of Texas (exclusive of corals and crustaceans
and exclusive of the fauna of the Escondido Formation).
The University of Texas, Publication 4101, 641 pp.
Stephensen, L.W. 1952. Larger invertebrate fossils of the
Woodbine Formation (Cenomanian) of Texas. Geological
Survey Professional Paper 242: 1–225.
Taylor, J.D. and N.J. Morris. 1988. Relationships of Neogastropods.
Malacological Review, Supplement 4: 167–179.
Thorson, G. 1944. The zoology of East Greenland marine
Gastropoda Prosobranchiata. Meddelelser om Grnland
121(13): 1–181.
Troschel, F. H. 1865. Das Gebiss der Schnecken zur
Bergru¨ ndung einer natu¨ rlichen Classification 2: 1–48.
von Koenen, A. 1885. U
¨ber eine Paleoca
¨ne fauna von
Kopenhagen. Abhandlungen der Ko
¨ninglichen Gesell-
schaft der Wissenschaften in Go
¨ttingen 32: 1–128.
Wilson, B. 1994. Australian Marine Shells. Prosobranch
Gastropods. Part 2. Odyssey Publishing, Kallaroo, 370 pp.
K. Amano et al., 2016 Page 121