Sunday, March 16, 2014

[Ichthyology • 2013] Schistura crocotula • A New Loach (Teleostei: Nemacheilidae) from Prachuap Khiri Khan Province, southern Thailand

Schistura crocotula Plongsesthee, Kottelat & Beamish 2013

Schistura crocotula, a new species, is described from Khanan River, Prachuap Khiri Khan Province, southern Thailand. It is distinguished from other species of Schistura in Southeast Asia by a depressed head; 6-11 dark brown bars against an orange background; the first bar is the widest, two bars are under dorsal fin; interspaces are often indistinct on posterior part of body; a thick black bar at the base of the caudal fin.

Diagnosis: Schistura crocotula is distinguished from the other species of the genus by the combination of the following characters: lateral line incomplete; 7 1/2 branched dorsal-fin rays; 8 + 8 branched caudal-fin rays; pelvic-fin origin in front of dorsal-fin origin; anterior nostril pierced on front side of a pointed flap reaching eye; body with 6-11 regular dark brown bars on an orange (in life) or gray (when preserved) background; the first bar is wider than other bars; one or two bars are under dorsal fin, 1-1.5 times wider than interspaces; bars and interspaces often indistinct posterior to anus and orange-brown in life; black basal caudal bar conspicuous, wide, reaching dorsal and ventral midlines.
Size: 48.5 mm SL

Distribution: Schistura crocotula is known only from the Khanan River in Bangsapan and Pranburi river in Pranburi, Prachuap Khiri Khan Province, peninsular Thailand. It is possible that some of the S. robertsi samples reported by Kottelat (1990) include more than one species and that some specimens from the eastern slope of peninsular Thailand (NIFI 2071) might be S. crocotula. The juvenile specimen from Tapi drainage (CMK 5179, 22.5 mm SL) also reported as S. robertsi is plain brown and uninformative; the identity of this population requires sampling of adult specimens.

Etymology: The species name crocotula is derived from the Latin name of a saffron garment (a saffron-coloured dress) and refers to the background colour of the live fish.

Plongsesthee, R., Kottelat, M. & Beamish, F. W. H.; 2013: Schistura crocotula, A New Loach from Peninsular Thailand (Teleostei: Nemacheilidae). Ichthyological Exploration of Freshwaters, 24 (2): 171-178.