Order Testudines Wagler, 1830 - turtles Suborder Cryptodira Cope, 1868 Superfamily Testudinoidea Batsch, 1788 Family Emydidae Rafinesque, 1815 - pond turtles Subfamily Deirochelyinae Agassiz, 1857 Genus Trachemys Agassiz, 1857 Trachemys gaigeae (Hartweg, 1939) - Big Bend slider Trachemys gaigeae hartwegi (Legler, 1990) - Nazas slider