Family Achiridae Rafinesque 1815 (Fig. 4A). American Soles; Lenguados Redondos, Suelas Americanas, Lenguados Derechos

Description: Body strongly compressed, flattened, rounded in shape; up to 35 cm; snout rounded; mouth small, oblique, a little under snout; lips fleshy, often fringed; eyes on the right side, close together, small to minute; preoperculum edge covered with skin but visible as a superficial groove; origin of the dorsal fin well before the eye, with the frontal rays in a skin envelope and hard to see; pectoral present or absent, better developed on the eye side, rudimentary or absent on the blind side; both pelvic fins present, right pelvic fin joined to the anal fin; caudal fin not connected to the dorsal and anal fins (Robertson & Allen 2015, Nelson et al. 2016). Distribution: Marine (often brackish) and freshwater; tropical and subtropical waters of America (Nelson et al. 2016). Two genera and four species in Nicaraguan freshwaters.