Sisor Hamilton, 1822

Ng, H. H., 2003, A revision of the south Asian sisorid catfish genus Sisor (Teleostei: Siluriformes), Journal of Natural History 37 (23), pp. 2871-2883 : 2872-2873

Sisor Hamilton, 1822

Sisor Hamilton, 1822: 208 , 379 (type species Sisor rabdophorus , by monotypy).

Diagnosis

Sisor is a distinctive genus distinguished from all other sisorid genera in possessing the following synapomorphies (de Pinna, 1996): mandibular laterosensory canal absent, vertebrae with transverse processes, anterior margin of pectoral spine with serrations, bony plates on surface of body, and first principal caudal fin ray enlarged and elongated as a filament.

Description

Head moderately narrow and very strongly depressed. Body extremely narrow and very strongly depressed. Skin with numerous small tubercles. Neurocranium exposed and extremely rugose, ornamented with numerous bumps and deep radial grooves. Nuchal plate trilobed (figure 2). Dorsal surface of body with a series of bony plates. First series of seven to eight plates located at dorsal-fin base and fused to dorsal-fin pterygiophores. Second series of 6–10 plates located posterior to dorsal fin; posteriormost plate of latter series with prominent median ridge terminating in backwards-projecting bony spur. Neural spines of vertebrae on caudal peduncle prominent, visible as series of median bony ridges along dorsal surface of caudal peduncle. Lateral surfaces of body with 66–77 distinct bony ossicles (lateral line ossicles), forming distinct ridge along lateral line.

Mouth inferior. Postlabial groove on lower jaw very prominent (as a depression) and uninterrupted. Upper lip with slender fleshy process at each corner. Lower lip with median thickened triangular pad.

Jaw teeth pointed and in two separate rectangular patches with small median indentation and rounded ends on both sides on upper jaw. Teeth on lower jaw present in two well-separated patches of roughly triangular shape. Eyes small, dorsolaterally situated and subcutaneous; located ventrolateral to bony ridge.