Major Subgroups

Pterosaur cladogram

After Unwin 2003

 

The classification of pterosaurs used here is based on the cladogram developed by Unwin (2003), which is shown above. While the phylogeny of pterosaurs is fairly well understood, other cladograms have been published that differ slightly in their structure; see Keller (2003) for one such alternative. For an overview of the methods and terminology used in creating a cladogram, visit the University of California's phylogenetic systematics page.

Basal Pterosaurs * Rhamphorhynchids * Ornithocheiroids * Ctenochasmatoids * Dsungaripteroids * Azhdarchoids


Eudimorphodon

From The Pterosaur Database; used with permission

 Basal Pterosaurs

Until recently, basal pterosaurs were grouped together as "Rhamphorhynchoids," a taxon that is no longer considered valid. The Triassic genus Preondactylus appears to be the most primitive known pterosaur. The Dimorphodontidae comprises two, probably insectivorous, genera: Dimorphodon and Peteinosaurus. Anurognathids have the most extensive temporal range of any basal pterosaurs, with a fossil record beginning in the Middle Jurassic and lasting until the Mid-Cretaceous. The Campylognathoididae includes the earliest known pterosaur, Eudimorphodon.

 Scaphognathus

From The Pterosaur Database; used with permission

 Rhamphorhynchids

Two subgroups make up the Rhamphorhynchidae, united by having less than 11 pairs of teeth and a "tongue-shaped" deltopectoral crest. Of the two subgroups, rhamphorhynchines are much more diverse, represented most famously by the Jurassic Rhamphorhynchus, which may have fed by skimming fish out of the water. The second group, the scaphognathines, is composed of two genera: Scaphognathus and Sordes. Both groups lived exclusively in the Jurassic.

 

Nyctosaurus & the early bird Ichthyornis

By Douglas Henderson; used with permission

 Ornithocheiroids

The Ornithocheiroidea comprises four groups (Istiodactylus, ornithocheirids, Nyctosaurus, and pteranodontids) united by several anatomical features. The most apparent of these are a notarium (fused dorsal vertebrae) and a unique ("ornithocheiroid") hand. All known members of this group lived in the Cretaceous. The Ornithocheiridae in particular were very diverse, with many specimens (including the marvelously named Arthurdactylus conandoylei) known from the Santana Formation in Brazil. Pteranodontids were among the largest pterosaurs, and sported some of the largest head crests. Their fossils, along with those of Nyctosaurus, are well-represented in Cretaceous deposits from the Central United States.

Pterodactylus

From The Pterosaur Database; used with permission

 Ctenochasmatoids

Ctenochasmatoids are defined by a number of synapomorphies in the skull. Perhaps the best known ctenochasmoid is Pterodactylus of the European Jurassic, which was in fact the first pterosaur described. The Late Jurassic-Early Cretaceous ctenochasmatids were unique among pterosaurs in being filter feeders, their jaws lined with large numbers of small teeth. The other taxa in this group are the basal Cycnorhamphus and the more derived Lonchodectes.

 Dsungaripterus

From The Pterosaur Database; used with permission

 Dsungaripteroids

The most distinctive feature of dsungaripteroids (Germanodactylus and the Dsungaripteridae) are their jaws, which were toothless towards the tip, with a small row of teeth further back. In Dsungaripterus itself, the jaw was also strongly curved upwards. It has been suggested that this odd skull morphology was useful for probing for and crushing the shells of intertidal invertebrates. Dsungaripteroids lived in the Late Jurassic and Early Cretaceous.

 

Quetzalcoatlus - Huge even compared to some of the biggest dinosaurs

Carnegie Museum, Pittsburgh, USA

 Azhdarchoids

Three main taxa comprise the Azhdarchoidea: Tapejara, Tupuxuara, and the azhdarchids. The former two are known from the Santana Formation of Brazil and supported ornate crests. The azhdarchids were named for a mythical Uzbek dragon and were in fact giants among pterosaurs. The largest pterosaur known from fairly complete material is Quetzalcoatlus of the North American Cretaceous, which had a wing span of 12 metres (though recent research has suggested that larger species may have existed). All azhdarchoids lived in the Middle and Late Cretaceous.



Author: John D. Orcutt

Last Updated: 11/2005

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