Germán Pequeño R. & Sylvia Sáez B.

Instituto de Zoología "Ernst F. Kilian", Universidad Austral de Chile. Casilla 567, Valdivia, Chile; gpequeno@uach.cl

Received 13-II-2001.        Corrected 21-VI-2001.        Accepted 11-II-2002.

Key words: Carcharhinus galapagensis, Carcharhinidae, Salas y Gomez, Chile.

This shark has been listed among Chilean species based on Randall and Cea-Egaña (1984), who gave a listing of vernacular names for the fishes of Easter Island (Pequeño 1989). Grove and Lavenberg (1997) record having photographed Carcharhinus galapagensis (Snodgrass and Heller 1905) at Salas y Gomez Is. There are no data to our knowledge of anyone examining specimens captured at either Easter Is. or Salas y Gomez Is. The distribution of C. galapagensis is generally discontinuous, including a broad range of distribution in both Atlantic and Pacific oceans, even to Japan (Taniuchi et al. 1985). The present study confirms the presence of this species in this isolated area using specimens caught on the CIMAR-5 Cruise. Both females, were obtained by hook and line fishing at a depth of over 25 m at Salas y Gomez Island (26º 28’ S, 105º 21’ W) on 7 Nov. 1999. One specimen measuring 1200 mm TL (Total length) was numbered IZUA-PM-2144 and the other of 790 mm IZUA-PM-2145, in the Collection of Fishes of the Instituto de Zoología, Universidad Austral de Chile. The mandibles of the specimens were compared with a known C. galapagensis mandible obtained from the California Academy of Sciences (CAS 39607) representing a 126 cm TL male from the Galapagos Islands.

There was a high concordance of diagnostic characteristics between our specimens and literature data on C. galapagensis.

Among the differences observed, the most notable was the length of the posterior margin of the first dorsal fin which was practically triple that cited by previous authors. The dental formula of our specimens was coincident with that of the mandible observed (CAS 39607). The smaller specimen (a) and larger specimen (b) showed the following dental formulae:

According to Easter Is. fishermen, C. galapagensisis is the only shark found at Salas y Gomez, where it is said to be abundant. This is the first instance in which analysis of taxonomic characteristics have been used to verify the shark’s identity and analyze variations in specific characters for comparative purposes which might indicate local differentiation of the species.

Grove, J.S. & R.J. Lavenberg. 1997. The fishes of the Galapagos Islands. Stanford University, 863 p.         [ Links ]

Pequeño, G. 1989. Peces de Chile. Lista Sistemática Revisada y Comentada. Rev. Biol. Mar., Valparaíso 24: 1-132.         [ Links ]

Randall, J.E. & A. Cea-Egaña. 1984. Native names of Easter Island Fishes, with Comments on the Origin of the Rapanuian People. Bernice Pahuai Bishop Mus., Occ. Pap. 25: 1-16.         [ Links ]

Taniuchi, T., H. Tachikawa, Y. Kurata & Y. Nose. 1985. Galapagos shark, Carcharhinus galapagensis, from the Ogasawara Islands, Japan. Jap. J. Ichthyol. 31: 449-452.         [ Links ]