The Rhamphorhynchoidea forms one of the two suborders of pterosaurs and regroup the primitive members of this group of flying reptiles. This suborder is paraphyletic in relation to the Pterodactyloidea, which arose from within the Ramphorhynchoidea, not from a more distant common ancestor. Ramphorhynchoids were the first pterosaurs to have appeared, in the late Triassic Period. Unlike their descendants the pterodactyloids, most rhamphorhynchoids had teeth and long tails, and most species lacked a bony crest, though several are known to have crests formed from soft tissue like keratin. They were generally small, and their fingers were still adapted to climbing . They disappeared at the end of the Jurassic period.