Prognatholiparis ptychomandibularis Orr & Busby 2001

This species is distinguished by the following set of characters: projecting lower jaw anterior to upper jaw; distinct flaps and folds of skin on snout, upper jaw, and ventral portion of mandible; large pelvic disc 37.4% HL; slender body; depth at pectoral fin base 20.5% SL, at anal-fin origin 19.0% SL; 2-6-8-1 pattern of cephalic lateralis pores, no coronal and post coronal pores; 2 epurals that are fused at the base; autogenous hypural plates; with pleural ribs; no pseudobranchiae; no subcutaneous layer; no pyloric caeca (Ref. 57784).

Dorsal soft rays (total): 37; Analsoft rays: 30; Vertebrae: 41

Species typical of moderately deep waters. Holotype had ostracods and rocks found in its stomach (Ref. 57784). Minimum depth from Ref. 58018.

Prognatholiparis, is a monospecific genus of marine ray-finned fish belonging to the family Liparidae, the snailfishes. It only species is Prognatholiparis ptychomandibularis, the wrinkle-jaw snailfish, which is found in the northeastern Pacific Ocean from near Seguam Island in the Aleutian Islands. It occurs at a depth of around 455 metres (1,493 ft). This species grows to a length of 8.8 centimetres (3.5 in) SL.