Peer Review #2 of "A new phylogenetic hypothesis of Tanystropheidae (Diapsida, Archosauromorpha) and other “protorosaurs”, and its implications for the early evolution of stem archosaurs (v0.1)"

Abstract

The historical clade "Protorosauria" represents an important group of archosauromorph reptiles that had a wide geographic distribution between the late Permian and Late Triassic. "Protorosaurs" are characterized by their long necks, which are epitomized in the genera Tanystropheus and Dinocephalosaurus. Recent phylogenetic analyses have indicated that "Protorosauria" is a polyphyletic clade, but the exact relationships of the various "protorosaur" taxa within the archosauromorph lineage remains unclear. Several taxa, although represented by relatively complete material, have previously not been assessed phylogenetically. We provide a historical overview of all taxa formerly considered as "protorosaurs" and present a new phylogenetic hypothesis that comprises a wide range of nonarchosauriform archosauromorphs with the most exhaustive sample of "protorosaurs" to date, including several recently described taxa from the eastern Tethys margin in modern China. The polyphyly of "Protorosauria" is confirmed. Tanystropheidae is recovered as a monophyletic group and the Chinese taxa Dinocephalosaurus orientalis and Pectodens zhenyuensis form a new non-archosauriform archosauromorph clade, Dinocephalosauridae. The well-known former "protorosaur" Prolacerta broomi