Pseudexostoma Chu, 1979 ^ZBK

Fig. 26

Pseudexostoma Chu, 1979 ^ZBK: 78, 81. (Type species: Glyptosternum yunnanensis Tchang, 1935 ^ZBK, by original designation). Gender neuter.

Diagnosis: Continuous post-labial groove; gill openings not extending onto venter; heterodont dentition in both jaws; outer teeth shovel-shaped and sparsely arranged in one or two rows, inner teeth conical and numerous; tooth patches separated in upper jaw; 16-18 branched pectoral rays.

Pseudexostoma ^ZBK is distinguished from Glyptosternon ^ZBK, Glaridoglanis ^ZBK, Euchiloglanis ^ZBK, Pareuchiloglanis ^ZBK and Parachiloglanis ^ZBK by having a continuous post-labial groove (Table 5). Pseudexostoma ^ZBK is distinguished from Myersglanis ^ZBK, Exostoma ^ZBK, Oreoglanis ^ZBK by having heterodont dentition in the upper jaw (vs. homodont = pointed in Myersglanis ^ZBK and Oreoglanis ^ZBK, and homodont = oar-shaped in Exostoma ^ZBK), and from Myersglanis ^ZBK and Exostoma ^ZBK by having heterodont dentition in the lower jaw (vs. homodont = pointed in Myersglanis ^ZBK, and homodont = oar-shaped in Exostoma ^ZBK). It is further distinguished from Exostoma ^ZBK by having 16-18 (vs. 10-11) branched pectoral rays, and from Myersglanis ^ZBK and Oreoglanis ^ZBK by having tooth patches separated in the upper jaw.

Description: 5-6 dorsal rays; 16-18 branched pectoral-fin rays; 6 pelvic-fin rays; 3-6 anal-fin rays. Head depressed; body elongate, depressed anteriorly. Eyes minute, dorsal, subcutaneous, dorsal. Lips thick, fleshy, papillated. Teeth of two distinct types in two wellseparated patches in both jaws; outer teeth shovel-shaped and sparsely arranged in one or two rows, inner teeth conical and numerous. Maxillary barbel with well-developed membrane, soft base, striated pad of adhesive skin. Gill openings narrow, extending only to a point above pectoral-fin base. Branchiostegal membranes confluent with isthmus. Coracoid process not externally visible. No thoracic adhesive apparatus. Paired fins plaited to form an adhesive apparatus.

Distribution: Irrawaddy and Salween drainages, Yunnan, China (Chu et al., 1999).