Description of a new Clarias species from southeast Asia based on morphological and genetical evidence (Siluriformes, Clariidae)

Clarias intermedius n, sp. is described from Central Kalimantan (Indonesia) . The new species belongs to the group of Asian Clarias species recognised by a very short distance between the occipital process and the dorsal fin o rigin and including C. macrocephalus and C. meladerma. From the former, it is distinguished amongst others by fewer gill rakers on the first branchial arch (16-23 vs. 27-33); from the latter is it easily recognised by the mor e numerous serrae on the anterior side of the pectoral spine (26-46 vs. 14- 22). Clarios meladerma and the new species are sympatric in Central Kaliman tan. In this area the existence of diagnostic enzymatic loci and the absenc e of intermediate genotypes between both species demonstrated their reprodu ctive isolation.