Vjushkovia triplicostata (von Huene 1960) Early Triassic ~240 mya, is a key taxon that is often overlooked. It was derived from a sister to Euparkeria at the base of the Rauisuchidae. Vjushkovia was also close to the base of a clade that included Qianosuchus, Yarasuchus, Ticinosuchus and the aetosaurs, Stagonolepis and Aetosaurus. Vjushkovia also nested at the base of the protoarchosaurs, including Decuriasuchus. Clearly this is a very important taxon that has been largely ignored in prior studies.
Compared to Euparkeria, the skull of Vjushkovia the naris was elongated and dorsal in position. The antorbital fenestra was triangular with the apex posterior. The orbit was smaller. The postorbital was more gracile but the squamosal was deeper and more robust. The retroarticular process was less distinct.
The cervicals are more robust and taller. There is an S-curve produced in the series. The dorsal neural spines are taller.
The pectoral girdle is more robust.
The pelvis is little changed. The metatarsals were shorter than the pedal digits. Despite the drawing, metatarsal 5 was probably hook-shaped, based on phylogenetic bracketing.
Vjushkovia nests at a phylogenetic crossroads. One lineage leads to a variety of taxa including the armored aetosaurs and the long-necked yarasuchids,
The other lineage leads to protoarchosaurs later divided later into crocodylomorphs and dinosaurs (aka archosaurs). The Ticinosuchidae is a new clade defined as Arizonasaurus, Ticinosuchus, their last common ancestor and all of its desecendents. Among those decendents are the long-necked yarasuchids and the armored aetosaurs. They are the proximal outgroups to the protoarchosauria, contra all prior published studies.