Pterodactyloidea (derived from the
Greek words πτερόν (
pterón, for usual
ptéryx) "wing", and
δάκτυλος (
dáctylos) "finger" meaning "winged finger", "wing-finger" or "finger-wing") is one of the two traditional suborders of
pterosaurs ("wing lizards"), and contains the most derived members of this group of flying reptiles. They appeared during the middle
Jurassic Period, and differ from the basal (though
paraphyletic)
rhamphorhynchoidea by their short tails and long wing
metacarpals (hand bones). The most advanced forms also lack teeth. Many species had well developed crests on the skull, a form of display taken to extremes in giant-crested forms like
Nyctosaurus and
Tupandactylus. Pterodactyloids (specifically the family
Azhdarchidae) were the last surviving pterosaurs when the order became extinct at the end of the
Cretaceous Period, together with the non-avian
dinosaurs and most marine reptiles.