Two new Leiocassis

[Silurus]

Ng, HH & KKP Lim, 2006. Two new species of Leiocassis (Teleostei: Bagridae), riverine catfishes from northeast Borneo. Ichthyological Exploration of Freshwaters 17: 165â??172.

Abstract

Two new species of bagrid catfishes in the genus Leiocassis are described from northeastern Borneo. Leiocassis collinus, new species, is described from the Kalabakan and Segama River drainages in Sabah. It can be distinguished from congeners in having a unique combination of: pectoral spine length 11.4-14.6 % SL, length of adipose-fin base 19.3-22.4 % SL, body depth at anus 15.8-17.9 % SL, caudal peduncle depth 8.3-9.4 % SL, head length 26.3-28.8 % SL, eye diameter 14.5-16.1 % HL, posterior tip of supraoccipital process separate from nuchal plate, and color pattern of faint light patches on darker body. Leiocassis tenebricus, new species, is described from the Kayan River drainage in Kalimantan Timur. It can be distinguished from congeners in having a uniform medium brown coloration (vs. mottled brown with cream or yellow patches), shorter pectoral spine (9.2-12.8 % SL vs. 13.0-21.3) and more vertebrae (42 vs. 38-40), and a unique combination of: length of adipose-fi n base 20.8-23.8 % SL, body depth at anus 14.0-15.1 % SL, caudal peduncle depth 6.9-7.6 % SL, head length 27.4-28.4 % SL, eye diameter 9.9-11.0 % SL, and posterior tip of supraoccipital process separate from nuchal plate.