Search

A new species of Pethia from Nagaland, northeastern India is distinguished from all its congeners in the Ganges-Brahmaputra drainage, Kaladan drainage and the Chindwin- Ayeyarwady drainage by the following combination of characters: lateral line complete with 22–23 pored scales up to tail-fin base, 3rd and 4th lateral line scales with minute humeral spot, a large elliptical to rounded black blotch covering 16th to 18th, or 17th to 19th lateral-line scales; live male specimens with reddish-green body above lateral line and reddish-orange beneath; dorsal, pectoral, pelvic, anal and caudal fins reddish-orange; dorsal fin in both sexes with broad black submargin. Genetic analysis based on the mitochondrial cytochrome oxidase unit I (cox1) suggests that the species is distinct from other known species of Pethia for which data are available.

Sicyopterus garra Hora, 1925 from the insular streams of South Andaman Islands was synonymized with Sicyopterus microcephalus described from Java, South East Asia and has retained this taxonomic status since then. Recent collections of Sicyopterus from the type locality of S. garra and the examination of syntypes of this species revealed significant morphological and genetic differences from S. microcephalus and the other Sicyopterus species with papillae on upper lip. S. garra is thus a valid species and not a synonym of S. microcephalus. S. garra differs from S. microcephalus in having fewer lateral scales 53-59 vs. 57-68, fewer zigzag series (12-14 vs. 13-16), a longer caudal peduncle length (16-21 vs. 13-17), and by having a high percentage of divergence in COI gene (5.5%-5.8%).

Channa stiktos, a new species of snakehead fish, is described from the River Kaladan and its tributaries, Mizoram, North Eastern India based on comparison of morphological and molecular features with closely related species. Channa stiktos is morphologically similar to C. ornatipinnis described from the Rakhine State of Myanmar, however, differs from it in having black spots on dorsal and ventral sides of the head (vs. no spots on dorsal and ventral sides of the head, but rather spots restricted to the post-orbital lateral region of the head), and lacking dark spot on the anal fin of juveniles (vs. presence of series of upto 10 dark spots). The molecular analysis, based on cytochrome c oxidase subunit I (COI) sequences, shows that C. stiktos is distinct from other close Channa species, except clade 3 of C. ornatipinnis, available in the GenBank (interspecies distance ranges from 8.24 – 25.33%). Channa stiktos clustered cohesively with clade 3 of C. ornatipinnis (only 1.43% genetic distance) indicating that they are conspecific. The genetic distance between Channa stiktos and C. ornatipinnis (from the type locality and another locality in the Ayeyarwaddy basin) are 8.24 – 8.59%, and between C. stiktos and C. pulchra is 12.92%, supporting the conclusion that they are different species.