Erythrosuchid

Classification

Erythrosuchids were formerly classified as thecodonts of the suborder Proterosuchia. This classification is no longer used by paleontologists, who now employ a cladistic approach. In this, erythrosuchids constitute an Archosauriformesclade that is an outgroup to the Archosauria proper. The presence of certain archosaurian features, such as the triradiate pelvic girdle, the fourth trochanter, and the third metatarsal longer than the fourth, indicate that erythrosuchids are closer to the true archosaurs than the Proterosuchidae, which lack these features. Thus the Erythrosuchidae occupy a transitional evolutionary position between the most primitive archisauriformes and more advanced Triassic archosaurs. The family was defined by Martin Ezcurra and colleagues in 2010 during the description of Koilamasuchus as "all taxa more closely related to Erythrosuchus africanus than to Proterosuchus fergusi or Passer domesticus (the house sparrow).