Abstract
Natural deposits of sunken wood provide an important habitat for deep-sea invertebrates. Deep-sea chitons in the primitiveorder Lepidopleurida are typically collected rarely and as single specimens. However, these animals have been recoveredin large densities associated with sunken wood in the tropical West Pacific, in groups of up to 50 individuals. Four deep-sea expeditions in the West Pacific, to the Philippines, Solomon Islands, and Vanuatu, recovered a large number of poly-placophorans. We have examined the morphology as well as the range and distribution of these species, based on the larg-est collection ever examined (more than 1300 individuals). These species show potentially adapted characters associatedwith exploitation of sunken wood as habitat, such as protruding caps on sensory shell pores (aesthetes) and large interseg-mental bristles with potential sensory function. In this study we investigated the twenty-two species recovered, includingseven newly described here (Leptochiton consimilis n. sp., L. angustidens n. sp., L. dykei n. sp., L. samadiae n. sp., L.longisetosus n. sp., L. clarki n. sp., L. schwabei n. sp.), and provide the first identification key to the 34 lepidopleuran chitons known from sunken wood worldwide.References
Annandale, N. & Stewart, F.H. (1909) Mollusca. Illustrations of the Zoology of the Royal Indian Survey Ship "Investigator" (1892–1900). Government Printing Office, Calcutta, pl. XXI-XXIII.
Bernardino, A.F., Smith, C.R., Baco, A., Altamira, I., & Sumida, Y.G. (2010) Macrofaunal succession in sediments around kelp and wood falls in the deep NE Pacific and community overlap with other reducing habitats. Deep Sea Research Part I: Oceanographic Research Papers, 57, 708–723.
Berry, S.S. (1917) Chitons taken by the United States Fisheries Steamer “Albatross” in the Northwest Pacific in 1906. Proceedings of the U.S. National Museum, 54, 1–18.
Cayré, P. & Richer de Forges, B. (2002) Faune mystérieuse des océans profonds. La Recherche, 355, 59–62.
d'Hondt, J.-L. (2006) Description de deux nouveaux genres et de trois nouvelles espèces de bryozoaires cténostomes. Bulletin de la Société Zoologique de France, 131, 247–260.
Dall, W.H. (1889) Report on the results of dredging, under the supervision of Alexander Agassiz, in the Gulf of Mexico (1877–78) and in the Caribbean Sea (1879–80), by the United States Coast Survey Steamer “Blake," Lieutenant-Commander C.D. Sigsbee, U.S.N., and Commander J.R. Bartlett, U.S.N., commanding. Report on the Mollusca, Pt. 2: Gastropoda and Scaphopoda. Bulletin of the Museum of Comparative Zoology, 18, 1–492.
Dell’Angelo, B. & Palazzi, S. (1989) Considerazioni sulla famiglia Leptochitonidae Dall, 1889 (Mollusca: Polyplacophora). III. Le species terziarie e quaternarie Europee, con note sistematiche e filogenetiche. Atti della prima Giornata di Studi Malacologici Centro Italiano di Studi Malacologici. 19–140.
Dell'Angelo, B. & Palazzi, S. (1991) Considerazioni sulla famiglia "Leptochitonidae" Dall 1889 (Mollusca, Polyplacophora). IV. Aggiunte e correzioni. Bollettino Malacologico, 27, 35–38.
Distel, D.L., Baco, A.R., Chuang, E., Morril, W., Cavanaugh, C. & Smith, C.R. (2000) Do mussels take wooden steps to deep-sea vents? Science, 493, 725–726.
Ferreira, A.J. (1979) The family Lepidopleuridae (Mollusca: Polyplacophora) in the eastern Pacific. The Veliger, 22, 145–165.
Ferreira, A.J. (1980) A new species of Lepidopleurus Risso, 1826 (Mollusca: Polyplacophora) in the Deep Waters of the Eastern Pacific. The Veliger, 23, 55–61.
Geiger, D. & Sasaki, T. (2008) Four new species of Anatomidae (Mollusca: Vetigastropoda) from the Indian Ocean (Reunion, Mayotte) and Australia, with notes on a novel radular type for the family. Zoosymposia, 1, 247–164.
Gray, J.E. (1847) Additional observations on Chitones. Proceedings of the Zoological Society of London, 15, 126–127.
Higo, S. (1973) A Catalogue of Molluscan Fauna of the Japanese Islands and Adjacent Area. [Privately published], Nagasaki, 521 pp.
Higo, S. Callomon, P. & Goto, Y. (1999) Catalogue and Bibliography of the Marine Shell-Bearing Mollusca of Japan. Elle Scientific Publishers, Osaka, 749 pp.
Higo, S. & Goto, Y. (1993a) A Systematic List of Molluscan Shells from the Japanese Islands and Adjacent Area. Elle Scientific Publishers, Osaka, 854 pp.
Higo, S. & Goto, Y. (1993b) Correction and Addition of Systematic List (Polyplacophora). Elle Scientific Publishers, Osaka, 10 pp.
Itoigawa, J., Nishimoto, H. & Tomida, S. (1977) Lepidopleurus morozakiensis, a new fossil Polyplacophora from the Miocene Morozaki group, central Japan. Bulletin of the Mizunami Fossil Museum—Mizunami, 4, 55–59.
Kaas, P. (1982) Leptochiton species (Polyplacophora: Leptochitonidae) of the Musorstom 1 (1976) and 2 (1980) Philippines expeditions. Basteria, 46, 87–92.
Kaas, P. (1990) New species and further records of known species of Polyplacophora from the tropical western Pacific. Basteria, 54, 175–186.
Kaas, P. (1991) Mollusca, Polyplacophora: Deep-water chitons from New Caledonia. In: Résultats des Campagnes Musorstom, Volume 7. Mémoires du Muséum national d'Histoire Naturelle, 150, 9–27.
Kaas, P. & Van Belle, R.A. (1980) Catalogue of Living Chitons (Mollusca: Polyplacophora), Backhuys, Rotterdam, 144 pp.
Kaas, P. & Van Belle, R.A. (1985) Monograph of Living Chitons (Mollusca: Polyplacophora), Volume 1. Order Neoloricata, Lepidopleurina. Backhuys, Leiden, 240 pp.
Kaas, P. & Van Belle, R.A. (1994) Monograph of Living Chitons (Mollusca: Polyplacophora), Volume 5 Suborder Ischnochitonina: Ischnochitonidae: Ischnochitoninae; (concluded) Callistoplacinae; Mopaliidae; Additions to Volumes 1-4, Brill, Leiden, 402 pp.
Kaas, P. & Van Belle, R.A. (1998) Catalogue of living chitons (Mollusca, Polyplacophora). Second, revised edition, Backhyus, Leiden, 204 pp.
Kiel, S. & Little, C.T.S. (2006) Cold-seep mollusks are older than the general marine mollusk fauna. Science, 313, 1429–1431.
Leloup, E. (1981) Résultats des campagnes Musorstom I: Philippines (18–28 Mars 1976): Mollusques: Polyplacophores. Mémoires Orstom, 91, 317–323.
Lindner, G. (1999) Muscheln und Schnecken der Weltmeere: Aussehen, Vorkommen, Systematik. 5th Edition, Verlagsgesellschaft mbH, München, 319 pp.
Montagu, G. (1803) Testacea Britannica or Natural History of British Shells, Marine, Land and Fresh Water, Including the Most Minute, Systematically Arranged and Embellished with Figures, Volume 1. [Privately published], London, 291 pp.
Murray, J. (1895) A summary of the scientific results obtained at the sounding, dredging and trawling stations of the H.M.S. Challenger, in: C.W. Thomson, & Murray, J. eds) Report on the Scientific Results of the Voyage of H.M.S. Challenger During the Years 1873–76, London, pp. 817–822.
Murray, J. & Reynard, A.F. (1891) Report on Deep-sea Deposits Based on the Specimens Collected During the Voyage of H.M.S. Challenger in the Years 1872 to 1876. Her Majesty's Stationery Office, London, 554 pp.
Nierstrasz, H.F. (1905) Die Chitonen der Siboga Expedition. Siboga Expeditie Monograph, 48, 1–112.
Nierstrasz, H.F. (1906) Remarks on the Chitonidae. Tijdschrift der Nederlandsche Dierkundige Vereeniging (2), 10, 141–171.
Ogasawara, K. (2003) Mollusca: Polyplacophora and allied taxa. Palaeontological Society of Japan Special Paper, 41, 277–278.
Pailleret, M., Haga, T., Petit, P., Privé-Gill, C., Saedlou, N., Gaill, F. & Zbinden, M. (2007) Sunken wood from the Vanuatu Islands: identification of wood substrates and preliminary description of associated fauna. Marine Ecology, 28, 233–241.
Rajagopal, A.S. & Subba Rao, N.V. (1974) On chitons from the Andaman and Nicobar Islands. Journal of the Marine Biological Association of India, 16, 398–411.
Saito, H. (1997) Deep-sea chiton fauna of Suruga Bay (Mollusca: Polyplacophora) with descriptions of six new species. National Science Museum Monograph, 12, 31–58.
Saito, H. (2000) Polyplacophora, in: T. Okutani. (ed Marine Mollusca of Japan. Tokai University Press, Tokyo, pp. 9–17.
Saito, H. (2001) Chitons (Mollusca: Polyplacophora) collected by the R/V Kotaka-Maru from Tosa Bay, Western Japan, with descriptions of two new species. National Science Museum Monograph, 20, 101–119.
Saito, H. (2004) Phylogenetic significance of the radula in chitons, with special reference to the Cryptoplacoidea (Mollusca: Polyplacophora). Bollettino Malacologico, Suppl. 5, 83–104.
Saito, H. (2005) Shelf and bathyl chitons (Mollusca: Polyplacophora) from the Nansei Islands, Southwestern Japan. National Science Museum Monograph, 29, 101–113.
Saito, H. (2006) A preliminary list of chitons (Mollusca: Polyplacophora) from the Sagami Sea. Memoirs of the National Science Museum, Tokyo, 40, 203–224.
Samadi, S., Quéméré, E., Lorion, J., Tillier, A., von Cosel, R., Lopez, P., Cruaud, C., Couloux, A. & Boisselier-Dubayle, M.-C. (2007) Molecular phylogeny in mytilids supports the wooden steps to deep-sea vents hypothesis. Comptes Rendus Biologies, 330, 446–456.
Sasaki, T. (2008) Micromolluscs in Japan: taxonomic composition, habitats, and future topics. Zoosymposia, 1, 147–232.
Schwabe, E. (2005) Polyplacophora, pp. 52–55. In: Dharma, B. (ed.) Recent & Fossil Indonesian Shells. Hackenheim, Germany, ConchBooks, 423 pp.
Schwabe, E. (2006a) Chitons (Mollusca, Polyplacophora) collected during the Thai-Danish Bioshelf Surveys (1996–2000) in the Andaman Sea, Indian Ocean. Journal of the Zoological Society of Wallacea, 2, 19–28.
Schwabe, E. (2006b) On a small collection of chitons from Papua New Guinea (Mollusca: Polyplacophora). Venus, 65, 97–112.
Schwabe, E. (2008) A summary of reports of abyssal and hadal Monoplacophora and Polyplacophora (Mollusca). Zootaxa, 1866, 205–222.
Schwabe, E., Sirenko, B. & Seeto, J. (2008) A checklist of Polyplacophora (Mollusca) from the Fiji islands. Zootaxa, 1777, 1–52.
Sigwart, J.D. (2008a) Gross anatomy and positional homology of gills, gonopores, and nephridiopores in “basal” living chitons (Polyplacophora: Lepidopleurina). American Malacological Bulletin, 25, 43–49.
Sigwart, J.D. (2008b) Phylogeny and evolution of basal living chitons (Mollusca: Polyplacophora: Lepidopleurida). Ph.D. Thesis, Queen’s University, Belfast, 420 pp.
Sigwart, J.D. (2009a) Morphological cladistic analysis as a model for character evaluation in primitive living chitons (Polyplacophora, Lepidopleurina). American Malacological Bulletin, 27, 95–194.
Sigwart, J.D. (2009b) The deep-sea chiton Nierstraszella (Mollusca: Polyplacophora: Lepidopleurida) in the West Pacific: taxonomy, morphology, and a bizarre ectosymbiont. Journal of Natural History, 43, 447–468.
Sigwart, J.D., Andersen, S.B., & Schnetler, K.I. (2007) First record of a chiton from the Palaeocene of Denmark (Polyplacophora: Leptochitonidae) and its phylogenetic affinities. Journal of Systematic Palaeontology, 5, 123–132
Sigwart, J.D., Schwabe, E., Saito, H., Samadi, S., & Giribet, G. (2011) Evolution in the deep sea: a combined analysis of the earliest diverging living chitons (Mollusca: Polyplacophora: Lepidopleurida). Invertebrate Systematics, 24, 560–572.
Sirenko, B.I. (1973) Amphipacific distribution of chitons (Loricata) and their new species in the North-West Pacific. Zoologiceskij Zurnal, 52, 659–667. English translation: Cowan, I. McT. & Smith, A.G. (1974) Of Sea and Shore, summer, 59–63.
Sirenko, B.I. (1977). Vertical distribution of chitons of the genus Lepidopleurus (Lepidopleuridae) and its new ultraabyssal species. Zoologicheskij Zurnal, 61, 1107–1110.
Sirenko, B.I. (1988) A new genus of deep sea chitons Ferreiraella gen. n. (Lepidopleurida, Leptochitonidae) with a description of a new ultra-abyssal species. Zoological Journal, 67, 1776–1786.
Sirenko, B.I. (1992) Nierstraszellidae fam. nov.—a new family of chitons (Polyplacophora, Lepidopleurida) from the bathyal Western Pacific. Ruthenica, 2, 81–90.
Sirenko, B.I. (1997a) The importance of the development of articulamentum for taxonomy of chitons (Mollusca, Polyplacophora). Ruthenica, 7, 1–24.
Sirenko, B.I. (1997b) Position in the system and the origin of deep-water chitons of the family Ferreiraellidae (Mollusca: Polyplacophora). Ruthenica, 7, 77–90.
Sirenko, B.I. (1998) One more deep water chiton Leptochiton vietnamensis sp. n. (Mollusca, Polyplacophora) living and feeding on sunken wood from the South China Sea. Ruthenica, 8, 1–5.
Sirenko, B.I. (2001) Deep-sea chitons (Mollusca, Polyplacophora) from sunken wood off New Caledonia and Vanuatu. Mémoires du Muséum national d'Histoire Naturelle, 185, 39–71.
Sirenko, B. (2004) The ancient origin and persistence of chitons (Mollusca, Polyplacophora) that live and feed on deep submerged land plant matter (xylophages). Bollettino Malacologico, Suppl. 5, 111–116.
Slieker, F.J.A. (2000) Chitons of the World: An Illustrated Synopsis of Recent Polyplacophora, L'Informatore Piceno, 154 pp.
Smith, E.A. (1906) Natural history notes H.M. marine survey steamer "Investigator" commander T.H. Heming, R.N. Series III. No. 10. On Mollusca from the Bay of Bengal and the Arabian Sea. Annals and Magazine of Natural History, 43, 245–264.
Taki, Is. (1938) Report of the biological survey of Mutsu Bay 31. Studies on chitons of Mutsu Bay with general discussion on chitons of Japan. The Science Reports of the Tôhoku Imperial University (4 [Biology]) 12, 323–423.
Taki, Is. (1961) Polyplacophora. Appendix. The Chiribotan, 12, 3–8.
Taki, Is. (1962) A list of Polyplacophora from Japanese Islands and vicinity. Venus, 22, 29–53.
Taki, Iw. (1964) Classification of the class Polyplacophora, with a list of Japanese chitons. Venus, 22, 401–414.
Taki, Is. & Taki, Iw. (1929) Studies on Japanese chitons (3). Venus, 1, 157–164.
Thiele, J. (1906) Ueber die Chitonen der deutschen Tiefsee-Expedition. Wissenschaftliche Ergebnisse der Deutschen Tiefsee-Expedition, 9, 327–334.
Thiele, J. (1908) Die antarktischen und subantarktischen Chitonen. Deutsche Südpolar Expedition 1901–1903, 10. Zoologie 2, 9–23.
Vermeij, G.J. (2011) Crucibles of creativity: the geographic origins of tropical molluscan innovations. Evolutionary Ecology, DOI: 10.1007/s10682-010-9458-2.
Vinther, J. (2009) The canal system in sclerites of Lower Cambrian Sinosachites (Halkieriidae: Sachitida): Significance for the molluscan affinities of the sachitids. Palaeontology, 52, 689–712.
Williams, S.T. (2007) Origins and diversification of Indo-West Pacific marine fauna: evolutionary history and biogeography of turban shells (Gastropoda, Turbinidae) Biological Journal of the Linnean Society, 92, 573–592.
Winckworth, R. (1940) A systematic list of the "Investigator" Mollusca. Proceedings of the Malacological Society, 24, 19–29.
Wolff, T. (1979) Macrofaunal utilization of plant remains in the deep sea. Sarsia, 64, 117–136.
Yearsley, J.M. & Sigwart, J.D. (2011) Larval transport modeling of deep-sea invertebrates can aid the search for undiscovered populations. PLoS One, 6, e23063.
Zelaya, D.G. & Geiger, D.L. (2007) Species of Scissurellidae and Anatomidae from sub-Antarctic and Antarctic waters (Gastropoda: Vetigastropoda). Malacologia, 49, 393–443.