Kullander & Noren, 2016
Danio htamanthinus, new species, is described from small streams in the vicinity of Htamanthi on the middle Chindwin River. It is most similar to D. choprae and D. flagrans from the Ayeyarwaddy River drainage, sharing the same elaborate colour pattern with dark vertical bars and a red interstripe along the posterior side, but is distinguished by the absence of a P+1 stripe and presence of a P stripe represented only by small spots. The uncorrected p-distance in the mitochondrial COI gene separates D. htamanthinus from D. choprae by 4.3% and from D. flagrans by 7.5%. The largest specimen is only 22.9 mm in standard length (male holotype), but the holotype and one other male, 19.5 mm SL, feature sex-specific pectoral-fin tubercles, and a female as small as 16.6 mm SL has ripening ova. In a phylogenetic analysis based on COI sequences, D. htamanthinus is sister taxon of D. flagrans+D. choprae, and those three species are sister group of D. margaritatus+D.erythromicron.
Keywords: Pisces, DNA barcode, freshwater, morphometrics, phylogeny, taxonomy
Etymology. The specific name htamanthinus is an adjective formed on the name of the village near which the type series was collected.
Geographical distribution and habitat. Danio htamanthinus is so far only known from two small streams near Htamanthi on the right bank of the Chindwin River (Fig. 2) and probably also in Shin Bway Yang further upstream in the Chindwin river basin. The type locality (Fig. 3) was a small, shallow stream with clear water, margined by low vegetation, coming out of the forest and crossing a dirt road under a bridge. Associated species were Paracanthocobitis cf. rubidipinnis (Nemacheilidae), Channa gachua (Channidae), Pethia meingangbii and P. thelys (Cyprinidae), and undetermined species of Badis and Dario (Badidae), Danio and Esomus (Cyprinidae). A second locality near Htamanthi was a flooded cleared area with stagnant clear water over grasses and a small trickle of stream feeding it (Fig. 4). Associated species here were Danio cf. quagga, Puntius chola, Pethia meingangbii, Rasbora ornata (Cyprinidae), and undetermined species of Amblyceps (Amblycipitidae) and Dario.