Avicephala (bird heads) is a possibly polyphyletic and therefore disused group of diapsid reptiles from the Late Permian and Triassic periods. Most of them have odd specialized grasping limbs and prehensile tails. The group includes Longisquama, Weigeltisaurus, Coelurosauravus, Vallesaurus, Hypuronector, Drepanosaurus, Dolabrosaurus, Langobardisaurus, Macrocnemus, Megalancosaurus, Rautiania and possibly Protoavis if it is a chimera.
Drepanosaurus
Description
Longisquama
Rautiania
The name Avicephala means "bird heads", in reference to the distinctive triangular skulls of these reptiles that mimic the shape of bird skulls. A few avicephalans, such as Hypuronector, even appear to have had pointed, toothless, bird-like beaks. This cranial similarity to birds has led a few scientists to theorize that birds descended from avicephalans like Longisquama, though a majority see the similarity simply as convergence. This similarity may also have led to the possible misidentification of the would-be "first bird", Protoavis.
