Knowra Diapsid Diapsid A diapsid is an amniote whose ancestral skull has two temporal openings behind each eye. The group includes living reptiles and birds and many extinct lineages.
Temporal fenestra : An opening in the skull behind the eye socket that provides space for jaw muscles or reduces skull weight. The two ancestral temporal fenestrae give diapsids their defining skull pattern.
Jaw adductor muscles : Muscles that close the jaws by elevating the lower jaw. Temporal openings are associated with space and attachment routes for these muscles.
Petrolacosaurus : An early Permian reptile often identified as one of the oldest known diapsids. Its fossil skull preserves the characteristic paired temporal openings in an early form.
Lepidosauria : A reptile group comprising lizards, snakes, and the tuatara and its extinct relatives. Lepidosaurs are a major living diapsid branch with distinctive skull and scale traits.
Amniote : A vertebrate whose embryo develops within an amnion, including mammals, reptiles, and birds. Diapsids are one major branch of amniote evolutionary diversity.
Skull kinesis : Movement between skull bones that allows parts of the skull to flex during feeding. Some diapsid lineages evolved mobile skull joints that expanded feeding mechanics.
Araeoscelidia : An extinct group of small, early diapsid reptiles from the Carboniferous and Permian periods. Araeoscelidians document early diversification near the base of diapsid evolution.
Archosauria : A reptile group that includes crocodilians, birds, dinosaurs, and their extinct relatives. Archosaurs represent another major diapsid branch, including both birds and crocodilians.
Anapsid : A traditional skull classification characterized by no temporal openings behind the eye sockets. Its contrast with the diapsid pattern helps clarify skull-based terminology.
Cranial kinesis in snakes : The extensive movement among skull bones that lets many snakes swallow large prey. Snakes demonstrate an extreme specialization of skull mobility within diapsids.
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