A New Loach of Schistura and Comments on the Genus

Schistura heterognathos Chen,sp.nov.is described based on specimens from the Nanla River,a tributary of the Lancangjiang River (upper Mekong River),in Yunnan Province of China.It is especially characterized by its abnormal jaws.The jaws are broad,thick and strong.The upper jaw has no dentoid process and there is a very small or no notch in the lower jaw.The dissociative margins of jaws are straight.The mouth is broad and transversal,its width approximately equals to snout length and is greater than the interorbital width.