This species is distinguished by the following characters: with joined vertical fins and loose, transparent, scaleless skin; body depth at origin of anal fin 13.0-16.5% SL; eyes are small or not externally visible; mouth almost horizontal; upper jaw ends well behind the eye; palatines edentate; jaws with small blunt or pointed teeth, no fangs; vomer with 3-7 fangs; anterior gill arch with 3-4 long rakers; D 92-118; A 61-78; pectoral fin 17-20 rays, with peduncle as long as or a little longer than high; pelvic fin with one ray; caudal fin rays 6-8; precaudal vertebrae 28-33, total vertebrae 77-87; vertebral centra in adults almost rectangular in lateral view; vertebrae generally poorly ossified; sagittal otolith rather large, oval and thin; penis partly covered ventrally by genital hood that ends in a medially placed clasper ventral to penis; no paired claspers in both sexes; fresh specimens with black peritoneum (Ref. 105129).