Pterodactyloidea

Pterodactyloids Temporal range: Late Jurassic - Late Cretaceous, 162.7–66 Ma PreЄ Є O S D C P T J K Pg N
Cast of a Pterodactylus antiquus specimen, Carnegie Museum of Natural History
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Order:	†Pterosauria
Clade:	†Caelidracones
Suborder:	†Pterodactyloidea Plieninger, 1901
Subgroups
†Kryptodrakon †Lophocratia Unwin, 2003 †Archaeopterodactyloidea †Eupterodactyloidea
Synonyms
Dracochira Haeckel, 1895

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.

"Pterodactyl" is also a common term for pterodactyloid pterosaurs, though it can also be used to refer to Pterodactylus specifically or (incorrectly) to pterosaurs in general. Well-known examples of pterodactyloids include Pterodactylus, Dsungaripterus, Pteranodon, and Quetzalcoatlus.

In 2014, fossils from the Shishugou Formation of China were classified as the most basal pterodactyloid yet found, Kryptodrakon. It is about 5 million years older than the oldest previously known confirmed specimens.^[1] Previously, a fossil jaw recovered from the Middle Jurassic Stonesfield Slate formation in the United Kingdom, was considered the oldest known. This specimen supposedly represented a member of the family Ctenochasmatidae,^[2] though further examination suggested it actually belonged to a teleosaurid stem-crocodilian instead of a pterosaur.^[1]

Classification

Pterodactyloidea is traditionally considered to be the group of short-tailed pterosaurs with long wrists (metacarpus), compared with the relatively long tails and short wrist bones of basal pterosaurs ("rhamphorhynchoids"). In 2004, Kevin Padian formally defined Pterodactyloidea as an apomorphy-based clade containing those species possessing a metacarpal at least 80% of the length of the humerus, homologous with that of Pterodactylus.

There are competing theories of pterodactyloid phylogeny. Below is a cladogram showing the results of a phylogenetic analysis presented by Andres, Clark & Xu, 2014.^[1] For alternate cladograms, see List of pterosaur classifications.

References