Color in life variable; body usually light to dark brown, with dorsal and lateral area darker than ventral surface. Pectoral fins hyaline, distal margin white and spotted. Pelvic fin spine and 1st ray forming an elongate, tentacular structure. 3 pairs of dorsolateral body plates; 4 pairs of ventrolateral body plates; tail rings 8 (rarely 9), mobile. A pair of deep pits posterior to orbit. Suborbital shelf concave, eye visible in ventral view. Ventral ridges of rostrum greatly expanded than dorsal ridges, each with laterally directed denticles. Anal papilla absent.