This early group did well from the Upper Triassic to the Lower Cretaceous. When we first see them in the fossil record they have developed three families, so biologists know their early evolution is not yet revealed. These three families are represented by the three genera "Rhamphorhynchus", "Dimorphodon" and "Eudimorphodon". At least one more family appears at the start of the Jurassic, the Anurognathidae.