A new species of the grenadier genus Coelorinchus from the seamounts in the southeastern Atlantic Ocean, with redefinition of C. vityazae (Teleostei: Gadiformes: Macrouridae)

Abstract

Re-investigation of the grenadier Coelorinchus vityazae endemic to the West Wind Drift Islands Province reveals species-level differences between the populations from the southeastern Atlantic and southwestern Indian oceans. The southeastern Atlantic populations (from Discovery and Gough seamounts) are described as a new species, C. inventionis sp. nov., characterized by a moderately short snout (27.7-33.9 % HL, vs. 32.0-38.7 % in C. vityazae) tipped with short, weakly tripartite terminal scute (vs. triangular and sharply pointed); uniformly thick, unpigmented lips (vs. fleshy, partly blackish upper lip with lateral portions expanded at middle in C. vityazae); modally i+17 or i+18 pectoral-fin rays (vs. i+15 or i+16), and anal-fin rays conspicuously darkened distally (vs. uniformly and finely peppered). Statistically significant differences between these two species were found for 28 of 39 morphometric characters. The Discovery and Gough specimens show a drastic difference in size of the light organ, which may reflect an initial stage of speciation within C. inventionis sp. nov. Iwamoto & Graham's (2008) key to the species of the C. fasciatus group is modified for inclusion of the new species.