Pterodactyloidea Pterodactyloidea 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) rhamphorhynchoids by their short tails and long wing metacarpals (hand bones). The most advanced forms also lack teeth, and by the late Cretaceous, all known pterodactyloids were toothless. Many species had well developed crests on the skull, a form of
Cretaceous A 140 Ma age for the Jurassic-Cretaceous boundary instead of the usually accepted 145 Ma was proposed in 2014 based on a stratigraphic study of Vaca Muerta Formation in Neuquén Basin, Argentina. Víctor Ramos, one of the authors of the study proposing the 140 Ma boundary age sees the study as a "first step" toward formally changing the age in the International Union of Geological Sciences. From youngest to oldest, the subdivisions of the Cretaceous period are: Late Cretaceous Maastrichtian – (66-72.1 MYA) Campanian – (72.1-83.6 MYA) Santonian – (83.6-86.3 MYA) Coniacian – (86.3-89.8 MYA) Turonian – (89.8-93.9 MYA) Cenomanian