Week 11 Vocab: Dinosaur Origins

Anapsids

A group of amniotes that have no skull fenestrae; turtles are a modern example; note: the validity of this clade is contested among palaeontologists.

Synapsids

A group of amniotes with only one pair of fenestrae; includes mammals and their extinct close relatives.

Dimetrodon

Famous, sail-backed synapsid that lived during the Permian period. Often mistakenly identified as a dinosaur.

Diapsids

A group of amniotes with two pairs of skull fenestrae the: supratemporal and laterotemporal fenestrae. Includes crocodiles, lizards, snakes, tuataras, dinosaurs, birds, and many extinct groups.

Lepidosauromorphs

Group of non-archosaur diapsids that includes lizards, snakes, tuatara, and many extinct groups.

Archosauromorphs

A group of diapsids that includes archosaurs and many more primitive groups; first evolved during the late Permian.

Archosaurs

A group of advanced archosauromorph diapsids that includes crocodiles, dinosaurs, birds, and many extinct groups; characterised by mandibular and antorbital fenestrae.

Antorbital fenestra

Opening in the skull in front of the orbits; characteristic of archosaurs.

Mandibular fenestra

Opening in the lower jaws of archosaurs

Avemetatarsalians

Special group of archosaurs characterized by ankles that flex like a hinge. Includes dinosaurs, pterosaurs and some of their close relatives.

Pseudosuchians

Group of archosaurs that includes modern crocodilians and all archosaurs more closely related to crocodilians than to birds; "crocodile-line" archosaurs. Have a peg and socket ankle joint.

Gorgonopsids

Group of carnivorous synapsids characterised by sets of elongated fangs; lived from the Middle to Late Permian.

Dicynodonts

A group of herbivorous synapsids with characteristic tusks and beaks; first evolved in Permian and thrived during the Triassic.

Cynodonts

A group of synapsids that led to modern day mammals; first evolved in the Late Permian.