Achirus declivis Chabanaud, 1940 .

Plainfin Sole; Suela Simple.

Distribution: Global: Western Atlantic Ocean; from Belize to southern Brazil; entering estuaries and littoral lagoons and ascending river courses; Costa Rica: To, Pa and Ma (Atlantic), 0– 7 m.a.s.l., Per, Dia.

Occurrence and conservation status: Nat, LC.

References: Angulo et al. (2013: 1010; listed, including taxonomic information and distributional data) and Robertson & Van Tassell (2019: 4328; detailed description, including illustrations, information on distribution, with a map, and ecology).