Sunday, April 18, 2021

[Ichthyology • 2021] Mustelus andamanensis • 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


Mustelus andamanensis 
  White, Arunrugstichai & Naylorn 2021
 
Andaman Smoothhound || DOI: 10.1007/s12526-021-01161-4

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 Günther, 1870. The use of buccopharyngeal patterns and vertebral counts in isolation from other morphological differences and molecular data in this genus is also discussed.

Keywords: Smoothhound sharks, Myanmar, Thailand, NADH2 sequences, Synonymy


Family Triakidae Gray, 1851

Genus Mustelus Linck, 1790

Mustelus mosis Hemprich & Ehrenberg, 1899
Arabian Smoothhound


Mustelus stevensi White & Last, 2008
Western Spotted Smoothhound


Lateral view of the fresh holotype of Mustelus andamanensis sp. nov., CSIRO H 8426-01 (female 427 mm TL), from Thailand. Scale bar = 50 mm

Mustelus andamanensis sp. nov. 
Andaman Smoothhound

Etymology: Specific name in allusion to the water body this species is currently known from, the Andaman Sea.

 Distribution: Known only from the Andaman Sea, with confirmed records from off Ranong Province of Thailand (Arunrugstichai et al. 2018). 


William T. White, Sirachai Arunrugstichai and Gavin J.P. Naylor. 2021. 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. ravidusMarine Biodiversity. 51: 42. DOI: 10.1007/s12526-021-01161-4