A large stocky shark; snout short and broad, somewhat rounded; eyes small, with lower eyelid; no spiracle; lip furrows at corners of mouth; mouth arched, ends well past eye; upper and lower front teeth with a single narrowly triangular straight point, mainly smooth, large fish have serrations on bases of upper teeth; 5 gill slits, last 2 over pectoral; spiracles usually absent (occasionally with very small spiracles); no ridge on back between dorsal fins; origin of first dorsal fin behind rear margin of pectoral fins; second dorsal fin 80-100% size of first; pectoral fins broad and slightly curved; anal fin large, a little smaller than second dorsal, with strongly notched rear margin; pit on top of tail base is longitudinal, straight; tail asymmetric, with well developed lower lobe.
Pale yellow brown on back and sides, yellowish or whitish below.
Attains about 340 cm; size at birth 60-65 cm.
A common inshore shark seen in a variety of habitats including rocky reefs, estuaries, and river mouths (may enter fresh water).
Depth: 0-90 m.
Tropical waters of the Atlantic and eastern Pacific (southern Baja and the Gulf of California to Peru.