Family Carcharhinidae Jordan & Evermann 1896 (Fig. 2A).

Requiem Sharks, Blue Sharks, Lemon Sharks, Sharpnose Sharks, Tiger Sharks, Whitenose Sharks, Whitetip Sharks; Cazones, Tintoreras, Tiburones

Description: Body elongate and robust; up to 740 cm in length; nostrils without barbels or grooves; nictitating eyelids internal; mouth large, arched, extends well behind eyes; teeth of variable sizes, blade-like; spiracles usually absent; five gill slits, the last two over the pectoral fin base; intestine with scroll valve, lacking spiral valve; two dorsal fins, with margins undulated; pelvic fins modified as copulatory organs in males; precaudal pit present; caudal fin strongly asymmetrical, with the lower lobe well developed and the upper lobe with an undulating ridge along its top edge and a notch under its tip (Robertson & Allen 2015, Nelson et al. 2016). Distribution: Marine, occasionally in freshwater rivers and lakes, tropical to warm temperate, continental and insular shelves and slopes and oceanic; Atlantic, Indian and Pacific oceans (Nelson et al. 2016). One genus and one species in Nicaraguan freshwaters.