studies found Dinocephalosaurus to have been closely related to but outside the Tanystropheidae. Martín Ezcurra and Richard J. Butler published a phylogenetic analysis based on a different dataset in 2018, which included all archosauromorphs from the middle Permian to the early Late Triassic known at the time. They also found that Dinocephalosaurus in a polytomy with Tanystropheidae and Trachelosaurus. Jesairosaurus was found to be the most closely-related genus to this polytomy. In 2020, Tiane De-Oliveira and colleagues added Dinocephalosaurus, Jesairosaurus, and Elessaurus to another dataset published by Adam Pritchard and colleagues in 2018, while also introducing modifications based on Ezcurra and Butler's dataset. Although their phylogenetic analysis recovered a poorly-resolved tree with a large polytomy, they found that Dinocephalosaurus and Jesairosaurus formed a group that was basal to Tanystropheidae and other archosauromorphs. In 2021, Stephan Spiekman and colleagues introduced yet another dataset specifically to test the phylogenetic relationships of protorosaurs. Different analyses were performed using datasets that incorporated different species and anatomical characteristics. They found that Dinocephalosaurus and Pectodens consistently formed a group, which they named as the Dinocephalosauridae. Some analyses (specifically, those excluding characters based on ratios or with orderings) also found that either Sclerostropheus and "Tanystropheus" antiquus fell inside this group. Either Fuyuansaurus or Jesairosaurus were found to be the closest relative of the dinocephalosaurids in some analyses. With the exception of Jesairosaurus, these genera of uncertain placement were found to be deeply nested within the Tanystropheidae by other analyses. Providing formal support for the original hypothesis of Rieppel and colleagues, Spiekman and colleagues found that placing Dinocephalosaurus as the sister group of Tanystropheus required a tree that was six steps longer, and therefore less likely. The following phylogenetic tree shows the results of their analysis that included ratio and ordered characters, but excluded "T." antiquus due to its instability: Paleobiology Neck and feeding The long neck of Dinocephalosaurus probably served a functional role. In particular, the length of the neck places a long distance between the head and the remainder of the body. This would have allowed Dinocephalosaurus to approach potential prey without the majority of its bulk being detected, which would have been effective in the murky waters of its habitat. In 2004, Li and colleagues suggested that Dinocephalosaurus may also have used its neck to capture its prey via suction feeding. After flexing its neck to the side (which would have been facilitated by the