EVERYDAY SCIENCE

Detailed explanation-1: -Turtles are the only living representatives of this clade and belong to one order variously referred to as Testudines, Testudinata, or Chelonia. Thus, when we refer to chelonians, we refer to turtles, tortoises, and terrapins as a group.

Detailed explanation-2: -All turtles are placed within the order Testudines (or Chelonia). Reptiles are traditionally classified according to the pattern of fenestration in the temporal region of the skull, and turtles are placed in the subclass Anapsida because they lack fenestration.

Detailed explanation-3: -Testudines-turtles. Diversity and Lower Taxonomy: The order testudines is a monophyletic clade containing 260 species of extant turtles, terrapins and tortoises in 13 families. Tortoises include just a single family (Testudinidae), which is phylogenetically embedded within the turtles.

Detailed explanation-4: -Classification: Reptilia; Eureptilia; Testudines; Pleurodira. Sister taxon: Clade containing Podocnemididae and extinct Bothremydidae.