Revision of the genus Mustelus (Carcharhiniformes: Triakidae) in the northern Indian Ocean, with description of a new species and a discussion on the validity of M. walkeri and M. ravidus

Abstract

The species of Mustelus Linck, 1790 occurring in the northern Indian Ocean are revised and a new species, Mustelus andamanensis sp. nov., is formally described. Previously considered to be conspecific with M. mosis Hemprich & Ehrenberg, 1899, the new species is currently only known from the Andaman Sea. The Red Sea and Arabian Sea populations of Mustelus mosis differ in vertebral counts and degree of coverage of buccopharyngeal denticles in the mouth, but these characters alone are not considered strong enough evidence to separate into two species. Mustelus andamanensis sp. nov. is genetically (based on NADH2 sequences) closest to M. mosis but differs in having a subdivided palatoquadrate (vs. palatoquadrate not divided). The new species is morphologically closest to M. widodoi White & Last, 2006, but differs in several morphological characters and on a molecular level. Mustelus stevensi White & Last, 2008 is confirmed from the northern Indian Ocean for the first time based on a single specimen taken off southeastern Myanmar. Mustelus walkeri White & Last, 2008 is found to be a junior synonym of M. antarcticus Gunther, 1870. The use of buccopharyngeal patterns and vertebral counts in isolation from other morphological differences and molecular data in this genus is also discussed.