Aphanosauria ("hidden lizards") is group of quadrupedal carnivorous avemetatarsalians. It includes a handful of mostly Triassic animals and is phylogenetically the oldest known avemetatarsalian clade.

This group was first recognized during the description of Teleocrater. Aphanosaurs were long-necked carnivores poorly adapted for running due to their short metatarsals, a biology more similar to basal archosaurs than advanced avemetatarsalians such as pterosaurs, lagerpetids, and early dinosaurs. In addition, they seemingly possess 'crocodile-normal' ankles (with a crurotarsal joint), showing that 'advanced mesotarsal' ankles (the form acquired by many dinosaurs, pterosaurs, lagerpetids, and advanced silesaurids) were not basal to the whole clade of avemetatarsalia. Nevertheless, they do have certain features which are present in certain avemetatarsalians but not pseudosuchians. These include having a supratemporal fossa on the frontal and hyposphene-hypantrum articulations. Although only known by a few genera, Aphanosaurs had a widespread distribution across Pangaea in the middle Triassic.

Aphanosaurs can be differentiated from other archosaurs due to possessing the following features:

Aphanosauria is formally defined as the most inclusive clade containing Teleocrater rhadinus and Yarasuchus deccanensis but not Passer domesticus (House sparrow) or Crocodylus niloticus (Nile crocodile).

This page was last edited on 18 February 2018, at 18:48.
Reference: https://en.wikipedia.org/wiki/Aphanosauria under CC BY-SA license.

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