Asilisaurus

Asilisaurus ( ); from Swahili, asili ("ancestor" or "foundation"), and Greek, (, "lizard") is an extinct genus of silesaurid archosaur. The type species is Asilisaurus kongwe. Asilisaurus fossils were uncovered in the Manda Beds of Tanzania, a formation typically dated to the Anisian stage of the Middle Triassic; however, some authors assert that the formation may be Ladinian or early Carnian instead. If it truly is Anisian, Asilisaurus would be one of the oldest known members of the Avemetatarsalia (animals on the dinosaur/pterosaur side of the archosaurian family tree). Asilisaurus was the first (ostensibly) non-dinosaur dinosauromorph recovered from Africa. Its discovery provides evidence for a rapid diversification of avemetatarsalians during the Middle Triassic, simultaneous with the diversification of pseudosuchians (crocodylian-line archosaurs).

Asilisaurus is known from a relatively large amount of fossils compared to most non-dinosaur dinosauromorphs. This has allowed it to provide important information for the evolution of other silesaurids and the origin of dinosaurs. It had several unique features compared to its close relatives, such as a lack of teeth at the front of the premaxilla and a lower jaw which was not only toothless at the tip, but also downturned. These indicate that it probably had a small beak on the tip of the snout. It was fairly basal among silesaurids, and retained some dinosaur-like features absent in advanced silesaurids, such as a supratemporal fossa and a quadrate which overlaps the squamosal. On the other hand, it also retains primitive features contrasting with dinosaurs, including two hip vertebrae, a closed hip socket, a crurotarsal ankle, and a non-vestigial fifth toe of the foot.