Monognathus rajui Bertelsen & Nielsen 1987

M. rajui differs from all other species of the genus by the following combination of characters: head short, snout blunt, skull length 3.4% TL, rostral fang with dorsal profile slightly convex forming an almost straight line with frontal profile of skull, dorsal fin origin above myomere number 7, anal fin origin below dorsal fin ray number 22, and no subdermal, lateral melanophores (Ref. 34506).

Dorsal soft rays (total): 88; Analsoft rays: 68