Pethia tiantian (Kullander & Fang 2005)

A member of the Puntius conchonius group uniquely distinguishable by the shape of the last unbranched dorsal fin ray which is slender, flexible and with short serrations posteriorly. Similar to P. cumingii, P. didi and P. meingangbii by presence of a dark vertical bar anteriorly on side and a dark round blotch on caudal peduncle; differs from these species by lateral line continued to caudal fin base vs. present on only 5 to 10 scales. Distinguished from the geographically close P. didi by body depth 35.4-39.8% SL vs. 40.4-48.2% SL and dorsal fin length 23.2-26.0% SL vs. 26.6-31.8% SL, and males with a single dark band across dorsal and anal fin vs. two series of black elongate marks in dorsal fin and one series of black marks in anal fin (Ref. 54351). Description: D. iii.8, iv.8; P. i.12, i.13, i.14; V. i.7, i.8; A. iii.5 (Ref. 54351).

Dorsal spines (total): 0; Dorsal soft rays (total): 11 - 12; Analspines: 0; Analsoft rays: 8; Vertebrae: 29 - 31

The type locality (Nan Hto Chaung) was a small hill stream, about 3 m wide on average, flowing through low forest, with grass and shrub along banks, and over a varied bottom with rock, gravel, and sand. The current was fast, with some riffle stretches. The water level was low, depth mostly less than 50 cm. There was no aquatic vegetation. The water was clear and colorless. Associated fauna included small species of Acanthocobitis (Balitoridae), Barilius, Devario, and Psilorhynchus (Cyprinidae) that were most abundant, but also species of Schistura (Balitoridae), Lepidocephalichthys (Cobitidae), Microrasbora (Cyprinidae), and Mastacembelus (Mastacembelidae), Badis pyema (Badidae), Heteropneustes fossilis (Clariidae), and Batasio tengana (Bagridae) were present. Also fished the larger Ma Kyaww Wa Chaung, into which the Nan Hto flows and samples consist of larger species, predominantly Garra sp. And Amblyceps murraystuarti. A single specimen was obtained from the Mali Hka River, a major river more than 100 m wide, but relatively shallow. Seining along 20 m stonebed shoreline yielded only one P. tiantian, one Acanthocobitis (Balitoridae), and juveniles of several cyprinid species (Banganasp., Neolissochilus sp., Schizothoraxsp., Semiplotus cirrhosus, Tor sp.) (Ref. 54351).

Occurs in a small hill stream, about 3 m wide on average, flowing through low forest, with grass and shrub along banks and over a varied bottom with rock, gravel and sand (Ref. 54351).

Pethia tiantian is a species of cyprinid fish that has only been recorded from streams in the vicinity of Putao in the far north of Myanmar. It grows to a length of 4.5 centimetres (1.8 in) SL.

It is generally brownish with a dark vertical bar just behind the operculum and a round dark blotch on the caudal peduncle. Other Pethia species are similarly marked but P. tiantian can be distinguished by its longer lateral line, reaching all the way back to the base of the caudal fin. P. didi, a similarly marked species found in the same drainage basin, differs from P. tiantian in having a deeper body and a longer dorsal fin with two rows of dark markings rather than one.