What is an Archosaur?
Q: What is an Archosaur?
A: An Archosaur is a large group of reptiles that includes crocodiles, birds, dinosaurs, and pterosaurs (flying reptiles). There are also a number of smaller extinct groups from the Triassic period.
Q: Are Archosaurs monophyletic?
A: Yes, they are definitely a monophyletic clade and do not include reptiles such as the Squamata (lizards and snakes) and the Sphenodontia (Sphenodon).
Q: What are some diagnostic features of Archosaurs?
A: Some diagnostic features of Archosaurs include teeth set in sockets which makes them less likely to be torn loose during feeding; openings in the skull in front of the eyes but behind the nostrils; small openings in the jaw bones to reduce weight; legs held under the body rather than sprawled; and a special ridge for attaching muscles to the femur.
Q: Did Archosaurs survive the Permian-Triassic extinction event?
A: Yes, it appears that either archosaurs or their immediate ancestors survived this catastrophic event.
Q: How did this event affect archosaurs?
A: This event allowed archosaurs to benefit from it by rapidly evolving into different types of aquatic and land tetrapods which dominated most of Mesozoic era.
