A new late Permian archosauromorph reptile from Germany enhances our understanding of the early diversity of the clade

The archosauromorphs (birds, crocodylians, and reptiles closer to them than to lepidosauromorphs) are major components of the extant tetrapod biodiversity, and their major diversification started during the Triassic. The oldest archosauromorphs are late Permian in age, but their record from this time interval is currently limited to five nominal species and a few other possible occurrences. Brief reports of probable archosauromorph skeletal remains from an upper Permian fissure filling just south of Korbach in Hesse (Germany) can potentially increase the scarce Palaeozoic record of the clade. Here we describe and compare an isolated anterior postaxial cervical vertebra from the Korbach locality (SMNK-PAL 76022). The vertebra has a parallelogram-shaped elongated centrum, which is 2.5 times longer than tall, and a low neural spine, resembling the morphology of other early archosauromorphs. In addition, a lunate fossa that separates the anterior rim of the centrum from the base of the prezygapophysis and the absence of posteriorly well-defined prezygapophyseal facets appear to be unique among Permo-Triassic diapsids and allow SMNK-PAL 76022 to be designated as the holotype of the new genus and species <i>Manistropheus kulicki</i>. A comprehensive phylogenetic analysis recovered <i>Manistropheus kulicki</i> at the base of Archosauromorpha. Morphological disparity analyses based on anterior-middle postaxial cervical characters show that Permian archosauromorphs taken together were already diverse before the end-Permian mass extinction (EPME). The cervical morphological disparity is low during the immediate aftermath of the EPME, but it increases during the late Induan and subsequently reaches a plateau of high values. This represents a faster diversification of this part of the skeleton after the EPME than has been found for other skeletal regions in previous studies. <i>Manistropheus kulicki</i> uncovers a small portion of the purported cryptic Permian archosauromorph diversity and highlights the importance of the Korbach locality to shed light on the continental tetrapod assemblages before the EPME. https://zoobank.org/urn:lsid:zoobank.org:pub:9CC99EAD-5214-4707-A79D-B3332E91E128