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First columbellid species (Gastropoda: Buccinoidea) from deep-sea hydrothermal vents, discovered in Okinawa Trough, Japan

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First columbellid species (Gastropoda: Buccinoidea) from deep-sea hydrothermal vents, discovered in Okinawa Trough, Japan

Abstract and Figures

The molluscan diversity of deep-sea chemosynthetic ecosystems in Japan has been in general well documented with about 80 described species, of which over half are gastropods (Sasaki et al. 2005; Fujikura et al. 2012; Sasaki et al. 2016). Recently, however, a number of novel hydrothermal vent sites were discovered in the area using multibeam echo-sounding (Nakamura et al. 2015), providing opportunities for new discoveries. As a part of ongoing studies documenting the biodiversity of such sites, we present the first record of Columbellidae from hydrothermal vents, with a new species recovered from Natsu and Aki sites, in the Iheya North hydrothermal field (for map and background on the vent field see Nakamura et al. 2015).
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592
Accepted by M. deMaintenon: 1 Nov. 2017; published: 13 Dec. 2017
ZOOTAXA
ISSN 1175-5326 (print edition)
ISSN
1175-5334
(online edition)
Copyright © 2017 Magnolia Press
Zootaxa 4363 (4): 592
596
http://www.mapress.com/j/zt/
Correspondence
https://doi.org/10.11646/zootaxa.4363.4.13
http://zoobank.org/urn:lsid:zoobank.org:pub:77801C93-5D28-4AA6-94B8-F1003E9B938F
First columbellid species (Gastropoda: Buccinoidea) from deep-sea
hydrothermal vents, discovered in Okinawa Trough, Japan
CHONG CHEN
1,4
, HIROMI KAYAMA WATANABE
2
& JUAN FRANCISCO ARAYA
3
1
Department of Subsurface Geobiological Analysis and Research (D-SUGAR), Japan Agency for Marine-Earth Science and
Technology (JAMSTEC), 2–15 Natsushima, Yokosuka 237–0061, Japan
2
Department of Marine Biodiversity Research (BIO-DIVE), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2–
15 Natsushima, Yokosuka 237–0061, Japan
3
Universidad de Atacama, Copayapu 485, Copiapó, Región de Atacama, Chile
4
Corresponding author. Tel: +81-(0)46-867-9717; E-mail: cchen@jamstec.go.jp
The molluscan diversity of deep-sea chemosynthetic ecosystems in Japan has been in general well documented with
about 80 described species, of which over half are gastropods (Sasaki et al. 2005; Fujikura et al. 2012; Sasaki et al.
2016). Recently, however, a number of novel hydrothermal vent sites were discovered in the area using multibeam echo-
sounding (Nakamura et al. 2015), providing opportunities for new discoveries. As a part of ongoing studies documenting
the biodiversity of such sites, we present the first record of Columbellidae from hydrothermal vents, with a new species
recovered from Natsu and Aki sites, in the Iheya North hydrothermal field (for map and background on the vent field see
Nakamura et al. 2015).
Columbellidae is a diverse family of caenogastropods in the superfamily Buccinoidea which include 70 genera and
several hundred species (deMaintenon 2014; Araya et al. 2016), most of which inhabit shallow waters and carry distinct
colour patterns. Generally, columbellids are small in size (mostly less than 20 mm although some large specimens exceed
40 mm) and are either active carnivores or scavengers (Squires 2015). More than 65 species are known from Japan alone
(Okutani 2017), although the deep-water diversity of the family remains poorly understood with a number of unnamed
species (Hasegawa 2009). The present new species is the first columbellid recorded not only from hydrothermal vent
ecosystems in Okinawa Trough, but from global vent communities as a whole. Prior to the present study, the only
columbellids reported from chemosynthetic ecosystems have been from whale-falls (Smith et al. 1989; Levin et al.
2002).
Material and methods
During the R/V K
AIYO
research cruise KY14-01, two newly detected hydrothermal vent sites named Natsu and Aki near
the Iheya North field (Nakamura et al. 2015) were explored for the first time using the ROV H
YPER
-D
OLPHIN
equipped
with a slurp gun for collection of biological samples. In the Natsu site, a bush of tubeworms (Lamellibrachia sp. and
Alaysia sp.) was collected, and nine specimens of a columbellid gastropod were recovered from their washings. In Aki
site, five specimens of the same columbellid were found in washings of Bathymodiolus mussels.
The columbellid specimens were measured for shell diameter (SD), shell height (SH), and height of last whorl (LW)
using Vernier callipers to ±0.1 mm accuracy. The radula was dissected out under a microscope and the remaining tissue
dissolved using 20% strength commercial bleach. Cleaned radula and protoconch were observed using a Hitachi
TM3000 SEM. Phylogenetic reconstruction was carried out using a 618 bp alignment of the cytochrome c oxidase
subunit I (COI) gene. In addition to the present columbellid species, other columbellid species with COI sequences
available on GenBank and three additional caenogastropods were included. The vetigastropod Turbo sazae Fukuda, 2017
served as an outgroup. Sequencing and phylogenetic methods follow that of Chen et al. (2017). Type materials are
deposited in the collections of the Japan Agency for Marine-Earth Science and Technology (JAMSTEC), the National
Science Museum, Tsukuba (NSMT) and the University Museum, the University of Tokyo (UMUT).
Zootaxa 4363 (4) © 2017 Magnolia Press ·
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NEW COLUMBELLID FROM OKINAWA VENTS
Taxonomy
Clade CAENOGASTROPODA Cox, 1960
Superfamily BUCCINOIDEA Rafinesque, 1815
Family COLUMBELLIDAE Swainson, 1840
Genus Astyris H. Adams & A. Adams, 1853
Astyris thermophilus n. sp.
http://zoobank.org/urn:lsid:zoobank.org:act:43FA9CFA-3756-4CBC-9861-41FAF66397B9
Type specimens. Holotype (Fig. 1A–D) [SH 8.5 mm, SD 4.3 mm, LW 4.1 mm], UMUT RM32644. Paratypes. #1 (Fig.
1E) [SH 8.3 mm, SD 4.5 mm, LW 4.6 mm], NSMT Mo 78990. #2 (Fig. 1F) [SH 7.4 mm, SD 4.2 mm, LW 4.1 mm],
periostracum removed with diluted bleach to reveal fine sculpture, operculum and radula removed for SEM, UMUT
RM32645. #3 [SH 7.1 mm, SD 4.0 mm, LW 4.0 mm], NSMT Mo 78991. #4 [SH 7.7 mm, SD 4.1 mm, LW 4.3 mm],
NSMT Mo 78992. #5 [SH 6.5 mm, SD 3.7 mm, LW 3.9 mm], JAMSTEC 1140053525. #6 [SH 3.0 mm, SD 1.7 mm, LW
1.6 mm], juvenile with intact protoconch, UMUT RM32646. All type specimens fixed and stored in 99% ethanol.
Type locality. Natsu hydrothermal vent site, Iheya North field, Okinawa Trough, Japan; 27°46.843’N,
126°54.024’E, 1074 m deep; 2014/Jan/24, collected by slurp gun, ROV H
YPER
-D
OLPHIN
Dive #1614, R/V K
AIYO
cruise
KY14-01, principal scientist: Ken Takai.
Additional material examined. Two specimens from type locality, fixed and stored in 99 % ethanol, used for
genetic barcoding (tissue dissolved). Five specimens, live collected, fixed and stored in 99% ethanol. Aki hydrothermal
vent site, Iheya North field, Okinawa Trough, Japan; 27°46.130’N, 126°54.159’E, 1087 m deep; 2014/Jan/25, collected
by slurp gun, ROV H
YPER
-D
OLPHIN
Dive #1614, R/V K
AIYO
cruise KY14-01, principal scientist: Ken Takai.
Etymology. From ‘Thermós’ (Greek), warm or hot, and ‘philíā’ (Greek), love or affection; combined to mean heat-
loving, referring to its habitat in hydrothermal vent fields.
Japanese Name.Yomotsu-mugi-gai’, meaning ‘mitrid from the underworld’.
Diagnosis. A moderate-sized (up to SH 8.5 mm) Astyris with rather tall-spired, uniformly white, thin, semi-
transparent shell; smooth including base, except 25 to 30 very fine spiral striae. Columella lacking columellar fold.
Periostracum thin, greyish brown. Protoconch paucispiral. Radula stenoglossate with acuspate centre plate, three sharp
cusps on each lateral.
Description. Shell (Fig. 1A–F) moderate-sized for genus (up to SH 8.5 mm), rather tall-spired. Apex always
decollate in adults, leaving at most three whorls remaining. Teleoconch thin, semi-transparent, uniformly white in
colouration. Periostracum thin, greyish brown, earlier whorls slightly darker coloured. Often covered by further sulfide
deposits. Teleoconch largely smooth except approximately 25 to 30 very fine, shallow, evenly spaced spiral striae present
across entire whorl (see Fig. 1F), increasing in strength anteriorly towards siphonal canal. Striations on posterior half of
shell usually too fine to detect when covered by periostracum. Whorls elevated, slowly expanding, slightly convex but
not angulated. Suture distinct, shallowly constricted. Aperture entirely lacking dentition, semi-circular in shape,
siphonate, approximately twice as tall as wide, posteriorly acuminate. Outer lip simple, not thickened, completely
smooth on inside. Columella straight, simple, with slightly thickened callus. Siphonal canal short with weakly
constricted but distinct siphonal notch. Protoconch (Fig. 1G) paucispiral, about 1.5 whorls, smooth, lacking velar sinus,
sculpture or distinct growth lines. Transition edge between protoconch and teleoconch clearly marked by a varix. Suture
of protoconch shallow, slightly higher than teleoconch.
Operculum (Fig. 1H) corneous, small, length about half of aperture height. Lamellate with lateral nucleus on right
often eroded away.
Radula (Fig. 1I) stenoglossate, typical of columbellids with one lateral on each side separated by an acuspate centre
plate instead of rachidian. Laterals sigmoid, well-supported, with three strong cusps. Two distal cusps sharper, longer,
closer spaced compared to basal cusp. Centre plate rectangular, slightly wider posteriorly, without sculpture.
Distribution and ecology. Only known from Natsu and Aki sites of the Iheya North hydrothermal field (Nakamura
et al. 2015), mid-Okinawa Trough, Japan. Found in tubeworm bushes attached on the tubes, presumably a predator of
other animals inhabiting the same habitat or alternatively it may be ovophagous and feed on eggs of other animals.
Remarks. The present new species is assigned to genus Astyris as it matches well with the diagnosis for the genus
given by McLean & Gosliner (1996), most notably by having a small, high-spired shell with smooth surface and a
paucispiral protoconch (Garcia 2009). Of those species currently in Astyris, the new species most closely resembles A.
permodesta (Dall, 1890) from methane seeps at Monterey Canyon and whale falls in California (Smith et al. 1989;
Bennett et al. 1994) and A. atacamensis Araya, Catalán & Aliaga, 2016 from northern Chile. Although A. permodesta
has been reported also from off Callao, Perú (Levin et al. 2002), this is likely in fact another record of A. atacamensis
(Sellanes 2017). Both of these species are easily separable from A. thermophilus n. sp. as they have a thicker, broader
CHEN ET AL.
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· Zootaxa 4363 (4) © 2017 Magnolia Press
shell with wider aperture and less constricted siphonal canal, as well as having spiral grooves on the base. The
pronounced columellar fold seen in A. atacamensis and the lirae inside the outer lip are also lacking in A. thermophilus n.
sp. Until the discovery of A. thermophilus n. sp., Astyris permodesta was the only other columbellid species known from
deep-sea chemosynthetic ecosystems.
Astyris thermophilus n. sp. is conchologically similar to Zemitrella cera Okutani, 1964 from 1000–3000 m deep off
Izu Islands, Japan (Okutani, 1964; 2017), but differs by having spiral striation across the entire teleoconch whorl
(sculpture is only present on the base in Z. cera) and a slightly longer siphonal canal. As the protoconch of Z. cera is
unknown, it is not transferred to Astyris at this point. Furthermore, the new species is also very similar to a yet
undescribed species reported from deep-water trawls and dredges carried out in northern Pacific coast of Honshu, Japan
(Mitrella sp. 1 sensu Hasegawa, 2009: figs. 162–166), but differs from that species in the spiral striae on the teleoconch
being less distinct and that the columella is always straight. At this point we cannot entirely dismiss the possibility that
Mitrella sp. 1 (sensu Hasegawa, 2009) may be conspecific with Astyris thermophilus n. sp. and the morphological
differences may be due to environmental factors.
The phylogenetic reconstruction (Fig. 2) confirmed the placement of the present new species within Columbellidae.
Its generic placement cannot be tested at present because sequences from other Astyris species were not available.
FIGURE 1. Astyris thermophilus n. sp. A–D. Holotype (UMUT RM32644). E. Paratype #1 (NSMT Mo 78990). F. Paratype #2
(UMUT RM32645), periostracum removed to show spiral striae. G. Protoconch of paratype #6, a juvenile specimen (UMUT RM
32646). H. Operculum of paratype #2 (UMUT RM32645). I. Radula of paratype #2, UMUT RM32645). Scale bars = 2 mm (A–F),
500 μm (G, H ), 20 μm (I).
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NEW COLUMBELLID FROM OKINAWA VENTS
FIGURE 2. Phylogenetic reconstruction using the COI gene (618 bp) showing Astyris thermophilus n. sp. nested within
Columbellidae. Node values indicate Bayesian posterior probability, those lower than 0.7 are omitted. The DDBJ/EMBL/GenBank
accession numbers for each sequence used are shown inside brackets (LC329027 and LC329028 for the two sequenced specimens of
A. thermophilus n. sp.).
Acknowledgements
The authors would like to express their sincere gratitude towards the operation team of ROV H
YPER
-D
OLPHIN
as well as
the Captain and crews of R/V K
AIYO
for their tireless support of the scientific activity during the research cruise KY14-
01. Kevin Monsecour and the handling editor Marta deMaintenon helped improve an earlier version of the manuscript.
The principal scientist on-board of cruise KY14-01, Ken Takai (JAMSTEC), is gratefully acknowledged for his diligent
execution of the research cruise. Ken Nagata (JAMSTEC) is thanked for his help in obtaining molecular sequences used
in this study. The genetic work was funded by a Japan Society for the Promotion of Science KAKENHI (grant no.
15K18602) awarded to Hiromi Kayama Watanabe.
References
Al-Rshaidat, M.M., Snider, A., Rosebraugh, S., Devine, A.M., Devine, T.D., Plaisance, L., Knowlton, N. & Leray, M. (2016) Deep
COI sequencing of standardized benthic samples unveils overlooked diversity of Jordanian coral reefs in the northern Red Sea.
Genome, 59 (9), 724–737.
https://doi.org/10.1139/gen-2015-0208
Araya, J.F., Catalán, R. & Aliaga, J.A. (2016) A new deep-water Astyris species (Buccinoidea: Columbellidae) from the southeastern
Pacific. Zootaxa, 4139 (1), 140–144.
https://doi.org/10.11646/zootaxa.4139.1.11
Bennett, B.A., Smith, C.R., Glaser, B. & Maybaum, H.L. (1994) Faunal community structure of a chemotrophic assemblage on whale
bones in the deep northeast Pacific Ocean. Marine Ecology Progress Series, 108, 205–223.
https://doi.org/10.3354/meps108205
Chen, C., Uematsu, K., Linse, K. & Sigwart, J.D. (2017) By more ways than one: Rapid convergence in adaptations to hydrothermal
vents shown by 3D anatomical reconstruction of Gigantopelta (Mollusca: Neomphalina). BMC Evolutionary Biology, 17, 62.
CHEN ET AL.
596
· Zootaxa 4363 (4) © 2017 Magnolia Press
https://doi.org/10.1186/s12862-017-0917-z
deMaintenon, M.J. (2014) Taxonomic revision of the species of Parvanachis Radwin, 1968 (Gastropoda: Columbellidae) from the
Gulf of Panama. Zootaxa, 3753 (3), 201–225.
https://doi.org/10.11646/zootaxa.3753.3.1
Fujikura, K., Okutani, T. & Maruyama, T. (2012) Deep-sea Life - Biological observations using research submersibles. 2
nd
Edition.Tokai University Press, Tokyo, 487 pp.
García, E.F. (2009) A new Astyris species (Gastropoda: Columbellidae) from the Gulf of Mexico, with notes on the genus. Novapex,
10, 5–8.
Hasegawa, K. (2009) Upper bathyal gastropods of the Pacific Coast of northern Honshu, Japan, chiefly collected by R/V Wakataka-
Maru. In: Fujita, T. (Ed.), Deep-sea Fauna and Pollutants off Pacific Coast of Northern Japan. National Museum of Nature and
Science Monographs, 39, pp. 225–383.
Levin, L., Gutiérrez, D., Rathburn, A., Neira, C., Sellanes, J., Muñoz, P., Gallardo, V. & Salamanca, M. (2002) Benthic processes on
the Peru margin: a transect across the oxygen minimum zone during the 1997–98 El Niño. Progress in Oceanography, 53, 1–27.
https://doi.org/10.1016/S0079-6611(02)00022-8
McLean, J.H. & Gosliner, T.M. (1996) Taxonomic Atlas of the Benthic Fauna of the Santa Maria Basin and the Western Santa
Barbara Channel. Vol. 9. Mollusca. Part 2. Gastropoda). Santa Barbara Museum of Natural History, Santa Barbara, CA, 228 pp.
Nakamura, K., Kawagucci, S., Kitada, K., Kumagai, H., Takai, K. & Okino, K. (2015) Water column imaging with multibeam echo-
sounding in the mid-Okinawa Trough: Implications for distribution of deep-sea hydrothermal vent sites and the cause of acoustic
water column anomaly. Geochemical Journal, 49, 579–596.
https://doi.org/10.2343/geochemj.2.0387
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, II, 15, 371–447.
Okutani, T. (2017) Marine Mollusks in Japan. 2
nd
Edition.Tokai University Press, Tokyo, 1382 pp.
Pelorce, J. (2017) Les Columbellidae (Gastropoda: Neogastropoda) de la Guyane française. Xenophora Taxonomy, 14, 4–21.
Sasaki, T., Ogura, T., Watanabe, H.K. & Fujikura, K. (2016) Four new species of Provanna (Gastropoda: Provannidae) from vents and
a seep off Nansei-shoto area, southwestern Japan. Ven u s , 74, 1–17.
Sasaki, T., Okutani, T. & Fujikura, K. (2005) Molluscs from hydrothermal vents and cold seeps in Japan: A review of taxa recorded in
twenty recent years (1984–2004). Ve n u s , 63, 87–133.
Sellanes, J. (2017) Comments on “A new deep-water Astyris species (Buccinoidea: Columbellidae) from the southeastern Pacific” by
Araya et al. 2016. Zootaxa, 4247 (1), 55–56.
https://doi.org/10.11646/zootaxa.4247.1.5
Smith, C.R., Kukert, H., Wheatcroft, R.A., Jumars, P.A. & Deming, J.W. (1989) Vent fauna on whale remains. Nature, 341, 27–28.
https://doi.org/10.1038/341027a0
Squires, R.L. (2015) First report of the Eocene gastropod Mitrella (Bastropia) (Neogastropoda: Columbellidae) from the northeast
Pacific and paleobiogeographic implications. The Nautilus, 129, 63–70.
... The studied specimens are in all details similar to the type material of A. thermophilus Chen, Watanabe et Araya, 2017 from hydrothermal vents of the Okinawa Trough at 1074 m (Chen et al., 2017). Nevertheless, our specimens originate from much more northward locality and lesser depths, as well as from methane seep rather than hydrothermal community, therefore their conspecifity with A. thermophilus can only be confirmed by molecular analysis. ...
... It represents the second record of the family from hydrothermal vents. Another species of Astyris, A. thermophilus Chen, Watanabe et Araya, 2017 was found at hydrothermal vents of the Okinawa Trough at 1074 m (Chen et al., 2017). From the latter one our species differs in the presence of thin and delicate but distinct axial lamellae, unknown previously in the species of the genus. ...
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