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Temporal range: Late Triassic - Late Cretaceous
Protosuchus richardsoni AMNH 3024 cast.jpg
A skeleton of Protosuchus richardsoni in the American Museum of Natural History
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Crocodyliformes
Informal group: Protosuchia
Mook, 1934

See text.

Protosuchia is a group of extinct Mesozoic crocodyliforms. They were small in size (~1 meter in length) and terrestrial. In phylogenetic terms, Protosuchia is considered an informal group because it is a grade of basal crocodyliforms, not a true clade.


Recent phylogenetic analyses have not supported Protosuchia as a natural group. However, two studies found a clade of Late Triassic-Early Jurassic animals:[1][2]

Both of these studies also found a clade more closely related to Hsisosuchus and Mesoeucrocodylia consisting of Late Jurassic-Late Cretaceous genera:[1][2]

However, other possible protosuchians from the Late Cretaceous of China-Mongolia, the Gobiosuchidae (Gobiosuchus and Zaraasuchus), have been found to either intermediate between these two clades,[1] or members of the Sichuanosuchus clade.[2] There is also another family of Late Jurassic-Late Cretaceous genera, the Shartegosuchidae (e.g. Kyasuchus, Shartegosuchus and Nominosuchus).

Below is a cladogram from Fiorelli and Calvo (2007).[2] Protosuchians are marked by the green bracket.












 "Kayenta Form" 
















  1. ^ a b c Pol D, Ji S-a, Clark JM, Chiappe LM. 2004. Basal crocodyliforms from the Lower Cretaceous Tugulu Group (Xinjiang, China), and the phylogenetic position of Edentosuchus. Cretaceous Research 25: 603-622.
  2. ^ a b c d Fiorelli LE, Calvo JO. 2007. The first "protosuchian" (Archosauria: Crocodyliformes) from the Cretaceous (Santonian) of Gondwana. Arquivos do Museu Nacional, Rio de Janeiro 65 (4): 417-459.