A New Whalefish Species of the Genus Cetomimus (Cetomimidae) from the Tropical Part of the Central Atlantic

Abstract

A new species of bathypelagic whalefishes of the genus Cetomimus is described; its two specimens were caught over the central tropical part of the Mid-Atlantic Ridge at the layers of 1500–0 and 2680–0 m. The species is characterized by the presence of 31/2 gill arches (with a small slit behind the third gill arch) and cavernous tissue developed only around the anus and above the bases of the first to sixth rays of the anal fin; large pores in the lateral line canal, which are approximately as wide as this canal; the absence of large, valve-shaped triangular outgrowths along the margin of septa between pores in the posterior part of the lateral line; 42–48 vertebrae; and 20, 17–18, and 18 rays in the pectoral, dorsal, and anal fins, respectively; 17–18 pores in the lateral line canal between the upper margin of the gill cover and the end of the caudal peduncle, as well as by some other diagnostic features. The first molecular genetic data for the described species (mtDNA COX-1 sequences, or DNA barcodes) and analysis of interspecific divergence in the genus Cetomimus are given