A new species of hillstream catfish with a wrinkled chin has been described from river drainages in western Thailand and southeastern Myanmar.
The new species is a member of the Asian hillstream catfish family Sisoridae and has been named Glyptothorax rugimentum by Heok Hee Ng and Maurice Kottelat in the latest issue of the Raffles Bulletin of Zoology.
Glyptothorax rugimentum is distinguished from other members of the genus except for G. indicus (an Indian species) in having the skin ridges of the thoracic adhesive apparatus extending forwards into the chin and lower lip.
The new species differs from G. indicus in having a wider head, larger eye, shorter nasal barbels, a narrower thoracic adhesive apparatus, pelvic-fin origin at vertical through base of last dorsal-fin ray, a more steeply-sloping posterior margin of the adipose fin, and the presence of light and dark vertical bands on the caudal peduncle.
Glyptothorax rugimentum is known only from the Ataran, Salween and Sittang River drainages in western Thailand and southestern Myanmar, and is named after the wrinkled chin region (Latin ruga = crease, and mentum = chin).
The presence of the skin ridges in the chin of G. indicus and G. rugimentum is restricted to these two species (all other Glyptothorax have a slightly wrinkled chin region which contains taste buds, but not the regular skin ridges present as part of the thoracic adhesive apparatus in all Glyptothorax).
For more information, see the paper: Ng, HH and M Kottelat (2008) Glyptothorax rugimentum, a new species of catfish from Myanmar and Western Thailand (Teleostei: Sisoridae). The Raffles Bulletin of Zoology 56, pp. 129"134.