Figure 1.A Central and South America B Study area with locations of examined Pacific (red) and Atlantic (orange) Gecarcinus lateralis (Freminville, 1835) (sensu Türkay 1973) and Gecarcinus nobilii sp. n. (green). Nicaragua, Pacific coast: (1) Rivas, San Juan del Sur. Costa Rica, Pacific coast, Puntarenas dept.: (2) Pochote Beach; (3) Hermosa Beach; (4) Drake Bay. Panama, Pacific coast: (5) Veraguas, Santa Catalina. Costa Rica, Atlantic coast, Limón dept.: (6) Parismina; (7) Puerto Viejo; (8) Manzanillo; (9) Punta Mona. Panama, Atlantic coast: (10) Bocas del Toro, Bluff Beach; (11) Colón, Maria Chiquita. Gecarcinus nobilii sp. n.: Colombia, Pacific coast: (12) Choco, Nuquí; (13) Buenaventura, Chucheros Beach; (14) Gorgona Island. Ecuador: (15) Esmeraldas, Punta Galera (type location); (16) Manabí, Ayampe; (17) Plata Island; (18) Santa Elena.