Ixalerpeton polesinensis

A Late Triassic lagerpetid from southern Brazil, Ixalerpeton was among the early-diverging bird-line archosaurs (avemetatarsalian) clustered near the shared origin of dinosaurs and pterosaurs. Ixalerpeton was small and lightly built, and unusually for a lagerpetid it preserves skull and forelimb material, not just hindlimbs. As a lagerpetid, Ixalerpeton is considered indicative of what the ancestors of the flying pterosaurs would have looked like, although it lived a bit too late in time to literally be a direct ancestor.