Archosauromorpha
Archosauromorpha (Greek for "ruling lizard forms") is a clade of diapsid reptiles containing all reptiles more closely related to archosaurs (such as crocodilians and dinosaurs, including birds) rather than lepidosaurs (such as tuataras, lizards, and snakes). Archosauromorphs first appeared during the late Middle Permian or Late Permian, though they became much more common and diverse during the Triassic period.
| Archosauromorphs Temporal range: Possible Middle Permian records | |
|---|---|
| Row 1: Sharovipteryx mirabilis and Crocodylus porosus Row 2: Pardalotus punctatus and Hyperodapedon fischeri Row 3: Tanystropheus longobardicus | |
| Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Archelosauria |
| Clade: | Archosauromorpha von Huene, 1946 |
| Subgroups | |
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Although Archosauromorpha was first named in 1946, its membership did not become well-established until the 1980s. Currently Archosauromorpha encompasses four main groups of reptiles: the stocky, herbivorous allokotosaurs and rhynchosaurs, the hugely diverse Archosauriformes, and a polyphyletic grouping of various long-necked reptiles including Protorosaurus, tanystropheids, and Prolacerta. Other groups including pantestudines (turtles and their extinct relatives) and the semiaquatic choristoderes have also been placed in Archosauromorpha by some authors.
Archosauromorpha is one of the most diverse groups of reptiles, but its members can be united by several shared skeletal characteristics. These include laminae on the vertebrae, a posterodorsal process of the premaxilla, a lack of notochordal canals, and the loss of the entepicondylar foramen of the humerus.