It was defined as the least inclusive clade containing Aetosaurus ferratus, Rauisuchus tiradentes, Prestosuchus chiniquensis, and Crocodylus niloticus (the living Nile crocodile) by Nesbitt (2011).

Moreover, the fibular condyle is hemicylindrical (half-cylinder shaped) in contrast to the more spherical structure of ornithosuchids, avemetatarsalians, and archosaur relatives such as Euparkeria and proterochampsians.

[1] Some suchians have a shallow longitudinal groove on the rear edge of the radius (inner forearm bone), although the distribution of this characteristic is poorly understood.

These traits are the presence of large, well-rimmed pits on either side of the dorsal (back) vertebrae, a humerus (upper arm bone) which has a symmetrical proximal portion when seen from the front, and a preacetabular process (front blade) of the ilium (upper hip bone) which has a moderate length, longer than it is high, but not longer than the pubic peduncle.

[6] Despite the broad distribution of this characteristic, its absence in some suchians makes it ambiguous whether it qualifies as a synapomorphy of Suchia, or alternatively evolved in several independent lineages within the group.

Under this new definition, Suchia included Gracilisuchus stipanicicorum, Aetosauria, "Rauisuchia", Poposauridae, Crocodylomorpha, and all descendants of their common ancestor.

[4] Nesbitt (2011) altered Sereno's definition slightly, as he defined Suchia as the least inclusive clade containing Aetosaurus ferratus, Rauisuchus tiradentes, Prestosuchus chiniquensis, and Crocodylus niloticus (the living Nile crocodile).

Such groups include Gracilisuchidae, Revueltosaurus, Aetosauria, Ticinosuchus, Poposauroidea, Loricata,[1][9] and possibly Erpetosuchidae,[2] Koilamasuchus,[3] Nundasuchus,[5] and/or Euscolosuchus.

[10] Below is a phylogenetic cladogram by Butler et al. in 2011 showing the cladistics of Archosauriformes, focusing mostly on Pseudosuchia:[9] Clade names follow Nesbitt 2011.

[1] Parasuchus Smilosuchus Pseudopalatus Riojasuchus Ornithosuchus Gracilisuchus Turfanosuchus Revueltosaurus Aetosaurus Stagonolepis Longosuchus Ticinosuchus Qianosuchus Ctenosauriscidae Poposaurus Lotosaurus Shuvosauridae Prestosuchus Saurosuchus Batrachotomus Fasolasuchus Rauisuchidae Crocodylomorpha Avemetatarsalia