Mogurnda kaimana is distinguished by the following combination of characters: 11 or 12 soft dorsal rays; 12 (rarely 11) soft anal rays; 15-17 (rarely 17) pectoral rays; 36-42 scales in lateral series; 21-25 predorsal scales; usually 9 (80% of specimens with 8-9) rakers on lower limb of first gill arch; body depth at pelvic origin 21.1-26.4% SL; body depth at anal origin 21.1-26.4% SL; head length 34.338.1% SL; interorbital width 11.3-14.2% SL; pelvic-fin length 18.6-25.9% SL; caudal-peduncle depth 12.4-15.2% SL; snout profile concave, especially noticeable in adults, but detectable in juveniles as small as 25 mm SL; and young specimens with a series of about 10 dark squares on sides, gradually developing pattern of numerous irregular spots and blotches on side, becoming increasingly melanistic with age, while adults entirely dark brown, nearly blackish (sometimes with hint of darker mottling) (Ref. 95614).