Taxonomic in the context of "Terrapin"

Terrapins or water tortoises are a group of several species of aquatic reptile of the order Testudines living primarily in fresh or brackish tidal waters, but have the clawed feet of tortoises and not flippers of marine turtles. In American English, they are referred to as marsh, pond, or tide-water turtles, with some species called pond sliders as well. Whereas tortoises are almost strict herbivores and frugivores — largely feeding on flowers, grasses, leaves, and fallen fruit — a great many terrapins are mainly carnivorous — largely feeding on amphibians, arthropods, freshwater fish, and molluscs — though some are herbivores. Terrapins are identified primarily with the taxonomic family Emydidae, but do not form a single taxon and may not be closely related, with some belonging to the families Geoemydidae, Pelomedusidae, Podocnemididae, and Chelydridae. Though primarily aquatic, terrapins do relatively frequently come to land for many reasons, but particularly to warm up by basking in the sun.