archosaur

American  

[ahr-kuh-sawr] / ˈɑr kəˌsɔr /

noun

1. any reptile of the subclass Archosauria, including the dinosaurs, pterosaurs, and crocodilians and characterized by two pairs of openings in the temporal region of the skull.

---

archosaur Scientific  

/ är′kə-sôr′ /

1. Any of various mostly reptilian animals of the subclass Archosauria. Archosaurs are diapsids that began to evolve in the late Permian Period, and are characterized by skulls with long, narrow snouts and teeth set in sockets. Archosaurs include the extinct dinosaurs and pterosaurs and the modern crocodilians and birds.

---

Other Word Forms

Derived Forms

• archosaurian
  adjective

Etymology

Origin of archosaur

1965–70; < New Latin Archosaurus, taken as singular of Archosauria, equivalent to Greek archo-, combining form of archós ruler, chief + saûr ( os ) -saur + New Latin -ia -ia

Example Sentences

Labrujasuchus belonged to the archosaur lineage that eventually gave rise to crocodiles, animals best known today for their four-legged bodies and tooth-filled jaws.

From Science Daily • May 29, 2026

Coprolites attributed to the archosaur Smok—a fearsome 5-meter-long bipedal predator with serrated teeth and powerful jaws—contained the crushed bones and teeth of its prey.

From Science Magazine • Nov. 27, 2024

"Analysing changes in body size throughout archosaur evolution, we found compelling evidence that it decreased sharply early in the history of the dinosaur-pterosaur lineage," Dr Kammerer said.

From BBC • Jul. 7, 2020

Some fossil evidence exists for dinosaurian parental care, and comparative biology supports this hypothesis since the archosaur birds and crocodilians display parental care.

From Textbooks • Jan. 1, 2015

The sail-backed reptile Ctenosauriscus from the Latest Early Triassic of Germany and the timing and biogeography of the early archosaur radiation.

From Scientific American • Jul. 4, 2012