Scomber indicus, a new species of mackerel (Scombridae: Scombrini) from Eastern Arabian Sea

Scomber indicus, a new species of mackerel is described based on the specimens collected from the eastern Arabian Sea. The species is differentiated from its nearest congener Scomber australasicus, in having 29-32 gill rakers on lower limb of first gill arch, posteriormost part of hypohyal blunt, with presence of a pit between the hypohyal and the ceratohyal and also in having a posteriorly directed haemal spine which is deeply curved in the basal region. Genetic differentiation and divergence between the newly described species and the 4 valid species of the genus Scomber viz., S. scombrus, S. japonicus, S. australasicus and S. colias were compared using cytochrome c oxidase 1 and cytochrome b gene sequences. The new species was found closest to S. colias followed by S. japonicus with Kimura 2 parameter (K2P) values of 1.4 and 1.8% respectively. In the phylogenetic tree, sequences of Scomber indicus sp. nov. formed a distinct well separated clade with significant bootstrap values as compared to the sequences of S. scombrus, S. japonicus, S. australasicus and S. colias indicating their distinctiveness and separate species status.

Taxonomy of the South American genus Pachypops Gill 1861 (Teleostei: Perciformes: Sciaenidae), with the description of a new species

Pachypops is a South American freshwater sciaenid genus characterized by having two anal-fin spines, three mental barbels, an inferior mouth, a swimbladder with a pair of short appendages anteriorly and a pair of longer appendages projected posteriorly, and the haemal spine of the first caudal distinctly expanded. Three valid Pachypops species are recognized herein. Of the six nominal species previously assigned to Pachypops, two are herein recognized as valid (Perca fourcroi and Micropogon trifilis), two are assigned to other sciaenid genera (Pachypops adspersus and Pachypops cevegei) and two are considered junior synonyms (Corvina biloba and Pachypops camposi). A seventh nominal species, Pachyurus nattereri, formerly considered a valid species of Pachyurus, is determined to be a junior synonym of Pachypops fourcroi, and lectotype and paralectotypes are designated for it. Pachypops fourcroi occurs in the Orinoco, Amazonas, Essequibo, Corantijn, and Approuague River basins, and Pachypops trifilis in rivers of Guyana and middle and lower reaches of the Rio Amazonas basin. A third valid species, Pachypops pigmaeus n. sp., is herein described from tributaries of the Rio Amazonas, Brazil.