Class Reptilia

∞ generated and posted on 2016.11.06 ∞

Especially land-adapted tetrapods that possess keratinized skin and develop from amniotic eggs but traditionally excluding birds and mammals.

The extant reptiles includes the lizards and snakes; the crocodiles and alligators; the turtles, and the tuataras. These reptiles by and larger are ectothermic.

More generally, there are endothermic reptilian descendants including dinosaurs (which presumably to at least some degree were endothermic), the birds (i.e., class Aves, which are descendants of the dinosaurs), and the mammals (i.e., class Mammalia, which are descendants of mammal-like reptiles that, in turn, form a distinct clade from all other extant reptiles).

Tetrapods can be distinguished into anapsids, synapsids, and diapsids on the basis of skull morphology. The ancestral state is that of anapsids, which literally have minimal holes (fenestra) in their skulls, i.e., as for the eyes and nostrils.

The synapsids have an additional pair of holes that is employed for jaw muscle attachment. These are the mammal-like reptiles and their descendants. The diapsids have a yet additional pair of holes in their skulls, also present for jaw muscles.

The diapsids are the "true reptiles", also known as the sauropsids. These animals include all as listed on this page except for the mammal-like reptiles and their descendants. These additional holes, more specifically, can be described as temporal fenestrae, owing to their location in them temple region.