(Family):Body depressed. Ventral surface markedly flattened. Tail stout, distinct from the disc. (Genus):Ventral surface of body completely covered with spinules. Pectoral fin lobe separated from tail. Disc subtriangular in outline. Subopercular spine absent. No lateral-line pore on ventral surface of tail. Teeth present on jaws, tongue, palatine, and vomer. Gill rakers in the form of oval plate covered with small denticles, present on all 4 arches. Single row of tubercle-like scales between anus and origin of anal fin. (Species):Pectoral fin rays 13 or more. Mouth wide, width 40〜45 % of DL. Rostrum short, length 30〜40 % of head depth. Main lateral-line pores 28〜29, subopercular series 10〜11, cheek series 10, premaxillary series 4.
Distribution:
The species distributed from north western South America to mouth of the Amazon.
Remarks:
This is the only species having 4 pores in premaxillary series of lateral-line canal and widest mouth, width 40〜45 % of DL in the genus. (Uyeno and Aizawa)