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Type: Article
Published: 2016-12-19
Page range: 401–432
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Bythaelurus bachi n. sp., a new deep-water catshark (Carcharhiniformes, Scyliorhinidae) from the southwestern Indian Ocean, with a review of Bythaelurus species and a key to their identification

Elasmo-Lab, Elasmobranch Research Laboratory, Schlägertwiete 5b, 21335 Lüneburg, Germany
Pacific Shark Research Center, Moss Landing Marine Laboratories, Moss Landing, CA 95039, USA Research Associate, South African Institute for Aquatic Biodiversity, Private Bag 1015, Grahamstown, 6140, South Africa Research Associate, Department of Ichthyology, California Academy of Sciences, 55 Music Concourse Drive, San Francisco, CA. 94118, USA
Pacific Shark Research Center, Moss Landing Marine Laboratories, Moss Landing, CA 95039, USA
ICHTHYS, Ichthyological Research Laboratory and Consultant, Hildesheimer Weg 13, 22459 Hamburg, Germany
Hollings Marine Laboratory, College of Charleston, Charleston, SC 29412
Pisces Chondrichthyes Elasmobranchii taxonomy new species morphology DNA analysis molecular phylogeny NADH2 western Indian Ocean


A new deep-water catshark, Bythaelurus bachi, is described based on 44 specimens caught on the southern Madagascar Ridge in the southwestern Indian Ocean. The new species is the only stout-bodied Bythaelurus with oral papillae in the region and is distinguished from all congeners by the plain beige to light gray-brown coloration, high diversity in dermal denticle morphology, and presence of composite oral papillae. Despite resemblance in body shape, Bythaelurus bachi n. sp. is distinguished from its closest congener, B. naylori Ebert & Clerkin, 2015, by the presence of numerous large, partially composite papillae on the tongue and roof of the mouth (vs. papillae lacking), plain light coloration (vs. medium to dark brown ground color, light fin edges and a distinctly dark dusky-colored snout), only slightly enlarged dermal denticles on the anterior upper caudal-fin margin (vs. dermal denticles distinctly enlarged), a higher diversity in dermal denticle morphology in general, and smaller maximum size and size at maturity. The distinction of both species is also supported by molecular results. The new species differs from all other congeners in the western Indian Ocean in the stout body shape of large specimens, coloration, larger size, as well as several morphometrics, including larger claspers, longer eyes and dorsal fins, and shorter pelvic—anal and pelvic—caudal spaces. The genus is reviewed, a key to its species given.



  1. Akhilesh, K.V., White, W.T., Bineesh, K.K., Ganga, U. & Pillai, N.G.K. (2013) Biological observations on the bristly catshark Bythaelurus hispidus from deep waters off the south-west coast of India. Journal of Fish Biology, 82 (5), 1582–1591.

    Alcock, A. (1891) Class Pisces. In: II.–Natural history notes from H.M. Indian marine survey steamer ‘Investigator’, Commander R.F. Hoskyn, R.N. commanding.–Series II., No. 1. On the results of deep-sea dredging during the season 1890–91. The Annals and Magazine of Natural History, 8 (6), 16–34.

    Alcock, A. (1899) A descriptive catalogue of the Indian deep-sea fishes in the Indian Museum. Being a revised account of the deep-sea fishes collected by the Royal Indian Marine Survey Ship Investigator. Indian Museum, Calcutta, 211 pp.

    Amante, C. & Eakins, B.W. (2009) ETOPO1 1 Arc-Minute Global Relief Model: Procedures, Data Sources and Analysis. NOAA Technical Memorandum NEDIS NGDC-24, 19 pp.

    Appukuttan, K.K. & Nair, K.P. (1988) Shark Resources of India, with Notes on Biology of a Few Species. In: Joseph, M.M. (Ed.) The First Indian Fisheries Forum, Proceedings. Asian Fisheries Society, Indian Branch, Mangalore, pp. 173–183.

    Bass, A.J., D’Aubrey, J.D. & Kistnasamy, N. (1975) Sharks of the east coast of southern Africa. II. The families Scyliorhinidae and Pseudotriakidae. Investigational Report, Oceanographic Research Institute, 37, 1–64.

    Chu, Y.-T. & Meng, Q.-W. (1982) Halaelurus immaculatus sp. nov. Pp. 301–302, 309 in Chu, Y.-T., Meng, Q.-W., Hu, A. & Li, S. (authors) Five new species of elasmobranchiate fishes from the deep waters of South China Sea. Oceanologica et Limnologica Sinica, 13 (4), 301–311. [in Chinese with English summary]

    Compagno, L.J.V. (1984a) FAO species catalogue. Vol. 4, Sharks of the World. An annotated and illustrated catalogue of shark species known to date (Part 1, Hexanchiformes to Lamniformes). FAO Fisheries Synopsis, 125, 4 (1). FAO, Rome, 249 pp.

    Compagno, L.J.V. (1984b) FAO species catalogue. Vol. 4, Sharks of the World. An annotated and illustrated catalogue of shark species known to date (Part 2, Carcharhiniformes). FAO Fisheries Synopsis, 125, 4 (2). FAO, Rome, pp. 251–655.

    Compagno, L.J.V. (1988) Sharks of the order Carcharhiniformes. Princeton University Press, New Jersey, 486 pp.

    Compagno, L.J.V. (1999) Checklist of Living Elasmobranchs. In: Hamlett, W.C. (Ed.) Sharks, Skates, and Rays – The Biology of Elasmobranch Fishes. The Johns Hopkins University Press, Baltimore, pp. 471–498.

    Compagno, L.J.V. (2005) Checklist of Living Chondrichthyes. In: Hamlett, W.C. (Ed.), Reproductive Biology and Phylogeny of Chondrichthyes – Sharks, Batoids and Chimaeras. Science Publishers, Inc., Enfield, pp. 503–548.

    Compagno, L.J.V., Stehmann, M. & Ebert, D.A. (1990) Rhinochimaera africana, a new longnose chimaera from southern Africa, with comments on the systematics and distribution of the genus Rhinochimaera Garman, 1901 (Chondrichthyes, Chimaeriformes, Rhinochimaeridae). South African Journal of Marine Science, 9 (1), 201–222.

    Compagno, L.J.V., Dando, M. & Fowler, S. (2005) A field guide to the Sharks of the World. Harper Collins Publishing Ltd., London, 368 pp.

    Concha, F., Bustamante, C., Oddone, M.C., Hernández, S. & Lamilla, J. (2010) Egg capsules of the dusky catshark Bythaelurus canescens (Carcharhiniformes, Scyliorhinidae) from the south-eastern Pacific Ocean. Journal of Fish Biology, 77 (4), 963–971.

    Ebert, D.A. & Clerkin, P.J. (2015) A new species of deep-sea catshark (Scyliorhinidae: Bythaelurus) from the southwestern Indian Ocean. Journal of the Ocean Science Foundation, 15, 53–63.

    Ebert, D.A., Fowler, S. & Compagno, L.J.V. (2013) Sharks of the world: a fully illustrated guide to the sharks of the world. Wild Nature Press, Devon, 528 pp.

    Francis, M.P. (2006) Distribution and biology of the New Zealand endemic catshark, Halaelurus dawsoni. Environmental Biology of Fishes, 75 (3), 295–306.

    Garman, S. (1913) The Plagiostomia (Sharks, Skates, and Rays). Memoirs of the Museum of Comparative Zoology at Harvard College, XXXVI, 1–528.

    Gill, T. (1862) Squalorum Generum Novum Descriptiones Diagnosticae. Annals of the Lyceum of Natural History of New York, 7 (1), 409–413.

    Günther, A. (1878) Preliminary Notices of Deep-Sea Fishes collected during the Voyage of H.M.S. ‘Challenger.’ Annals and Magazine of Natural History, 2 (5), 17–28.

    Herman, J., Hovestadt-Euler, M. & Hovestadt, D.C. (1990) Part A: Selachii. No. 2b: Order : Carcharhiniformes—Family : Scyliorhinidae. In: Stehmann (Ed.), Contributions to the study of the comparative morphology of teeth and other relevant ichthyodorulites in living supraspecific taxa of Chondrichthyan fishes. Bulletin de l'Institut Royal des Sciences Naturelles de Belgique, Biologie, 60, 181–230.

    Hovestadt, D.C. & Hovestadt-Euler, M. (1995) Additions to the fauna of the Boom Clay Formation of Beglium (Rupelian, Oligocene). Taxonomic adjustments on the Scyliorhinidae and Rajoidei, discovery of a dasyatid species (Pisces, Chondrichthyes) and of a curculionid species (Insecta, Coleoptera). Belgian Geological Survey Professional Paper, 278, 261–282.

    Ishihara, H., Treloar, M., Bor, P.H.F., Senou, H. & Jeong, C.H. (2012) The Comparative Morphology of Skate Egg Capsules (Chondrichthyes: Elasmobranchii: Rajiformes). Bulletin of the Kanagawa Prefectural Museum (Natural Science), 41, 9–25.

    Kaschner, C.J., Weigmann, S. & Thiel, R. (2015) Bythaelurus tenuicephalus n. sp., a new deep-water catshark (Carcharhiniformes, Scyliorhinidae) from the western Indian Ocean. Zootaxa, 4013 (1), 120–138.

    Last, P.R. & Stevens, J.D. (2008) Bythaelurus incanus sp. nov., a new deepwater catshark (Carcharhiniformes: Scyliorhinidae) from northwestern Australia. In: Last, P.R., White, W.T. & Pogonoski, J.J. (Eds.) Descriptions of New Australian Chondrichthyans. CSIRO Marine & Atmospheric Research Paper No. 022, pp. 123–128.

    Lopez, S., Zapata-Hernández, G., Bustamante, C., Sellanes, J. & Meléndez, R. (2013) Trophic ecology of the dusky catshark Bythaelurus canescens (Günther, 1878) (Chondrychthyes: Scyliorhinidae) in the southeast Pacific Ocean. Journal of Applied Ichthyology, 29 (4), 751–756.

    McCosker, J.E., Long, D.J. & Baldwin, C.C. (2012) Description of a new species of deepwater catshark, Bythaelurus giddingsi sp. nov., from the Galápagos Islands (Chondrichthyes: Carcharhiniformes: Scylorhinidae). Zootaxa, 3221, 48–59.

    Meléndez, R. & Meneses, D. (1989) Tiburones del talud continental recolectados entre Arica (18º19'S) e Isla Mocha (38º30'S), Chile. Investigaciones Marinas, Valparaíso, 17, 3–73.

    Nair, R.V. & Appukuttan, K.K. (1973) Observation on the food of deep sea sharks Halaelurus hispidus (Alcock), Eridacnis radcliffei Smith and Iago omanensis Compagno and Springer. Indian Journal of Fisheries, 20 (2), 575–583.

    Nair, R.V. & Lal Mohan, R.S. (1973) On a new deep sea skate, Rhinobatos variegatus, with notes on the deep sea sharks Halaelurus hispidus, Eridacnis radcliffei and Eugaleus omanensis from the Gulf of Mannar. Senckenbergiana biologica, 54 (1/3), 71–80.

    Nakaya, K., Sato, K., Iglésias, S.P. & White, W.T. (2008) Methodology for the taxonomic description of members of the genus Apristurus (Chondrichthyes: Carcharhiniformes: Scyliorhinidae). In: Last, P.R., White, W.T. & Pogonoski, J.J. (Eds.) Descriptions of new Australian chondrichthyans. CSIRO Marine & Atmospheric Research Paper No. 022, pp. 49–60.

    Naylor, G.J.P., Ryburn, J.A., Ferigo, O. & Lopez, A. (2005) Phylogenetic relationships among the major lineages of modern elasmobranchs. In: Hamlett, W.C. (Ed.) Reproductive Biology and Phylogeny of Chondrichthyes – Sharks, Batoids and Chimaeras. Science Publishers, Inc., Enfield, pp. 1–25.

    Raje, S.G., Mathew, G., Joshi, K.K., Nair, R.J., Mohanraj, G., Srinath, M., Gomathy, S. & Rudramurthy, N. (2002) Elasmobranch Fisheries of India – An Appraisal. CMFRI special publication 71. CMFRI, Cochin, pp. 1–76.

    Sabaj Pérez, M.H. (Ed.) (2014) Standard Symbolic Codes for Institutional Resource Collections in Herpetology and Ichthyology: an Online Reference, Version 5.0 (22 September 2014). Available from (accessed 13 December 2014).

    Sakaff, H. & Esseen, M. (1999) Occurrence and Distribution of Fish Species off Yemen (Gulf of Aden and Arabian Sea). Naga ICLARM Quaterly, 22 (1), 43–47.

    Séret, B. (1987) Halaelurus clevai, sp. n., a new species of catshark (Scyliorhinidae) from off Madagascar, with remarks on the taxonomic status of the genera Halaelurus Gill & Galeus Rafinesque. J.L.B. Smith Institute of Ichthyology Special Publication, 44, 1–27.

    Springer, S. (1971) A new cat shark (Scyliorhinidae) from New Zealand. Records of the Dominion Museum, 7 (18), 235–241.

    Springer, S. (1979) A revision of the catsharks, family Scyliorhinidae. NOAA Technical Report NMFS Circular, 422, 1–152.

    Springer, S. & D’Aubrey, J.D. (1972) Two New Scyliorhinid Sharks from the East Coast of Africa with Notes on Related Species. Oceanographic Research Institute, Investigational Report, 29, 1–19.

    Springer, V.G. & Garrick, J.A.F. (1964) A survey of vertebral numbers in sharks. Proceedings of the United States National Museum, 116, 73–96.

    Stehmann, M.F.W. (2002) Proposal of a maturity stages scale for oviparous and viviparous cartilaginous fishes (Pisces, Chondrichthyes). Archive of Fishery and Marine Research, 50 (1), 23–48.

    Tizard, T.H., Moseley, H.N., Buchanan, J.Y. & Murray, J. (1885) Narrative of the cruise of H.M.S. Challenger with a general account of the scientific results of the expedition. Report on the scientific results of the voyage of H.M.S. Challenger during the years 1873–76. Narrative 1 (2), 511–1110.

    Valenzuela, A., Bustamante, C. & Lamilla, J. (2008) Morphological characteristics of five bycatch sharks caught by southern Chilean demersal longline fisheries. Scientia Marina, 72 (2), 231–237.

    Weigmann, S. (2016) Annotated checklist of the living sharks, batoids and chimaeras (Chondrichthyes) of the world, with a focus on biogeographical diversity. Journal of Fish Biology, 88 (3), 837–1037.

    Weigmann, S., Stehmann, M.F.W. & Thiel, R. (2013) Planonasus parini n. g. and n. sp., a new genus and species of false cat sharks (Carchariniformes, Pseudotriakidae) from the deep northwestern Indian Ocean off Socotra Islands. Zootaxa, 3609 (2), 163–181.

    Weigmann, S., Stehmann, M.F.W. & Thiel, R. (2015) Okamejei ornata n. sp., a new deep-water skate (Elasmobranchii, Rajidae) from the northwestern Indian Ocean off Socotra Islands. Deep-Sea Research II, 115, 18–29.

    White, W.T. & Last, P.R. (2013) Notes on shark and ray types at the South China Sea Fisheries Research Institute (SCSFRI) in Guangzhou, China. Zootaxa, 3752 (1), 228–248.