Abstract
Clarias gracilentus, a new Southeast Asian walking catfish species, is described from Phu Quoc Island (Vietnam) off the coast of southeastern Cambodia and from mainland southeastern Cambodia. The new species is a member of the C. nieuhofii species complex, and can be distinguished from congeners in the complex in having a combination of: head width 11.9-12.9% SL, distance between the occipital process and the base of the first dorsal-fin ray 5.3-8.4% SL, pectoral-fin length 8.5-10.1% SL, body depth at anus 8.2-11.7% SL, pelvic-fin length 4.3-5.5% SL, length of anal-fin base 60.0-63.9% SL, eye diameter 5.4-7.2% HL, interorbital distance 42.7-48.0% HL, occipital-process length 7.8-14.7% HL, 96-101 dorsal-fin rays, 84-89 anal-fin rays and 80-84 total vertebrae.
NSTL