New stem lepidosaurs from Vellberg, Germany: implications for palaeoecology in the early diversification of Lepidosauromorpha

Lepidosauromorphs account for roughly a third of the living diversity of land vertebrates and yet their origin and early evolutionary history remain highly contentious. The fossil record of early lepidosauromorphs has historically been very poor, but this has changed in recent years with new taxa having been reported from Europe and North and South America, such as the contributions from Vellberg, south-western Germany. Here, we describe four new early lepidosauromorph taxa from the same locality (Airistagiz seegisi, Hohlachia multidens, Klainjosaura staroskalja, gen. et sp. nov. and an unnamed taxon), raising the number of known lepidosauromorphs from three to seven. The new taxa add to the anatomical diversity of early lepidosauromorphs, in both cranial and postcranial regions, with suspensorium and tooth implantation features indicating the presence of an ecological mechanism that could explain their sympatric existence without direct competition. Variations in temporal morphology may represent different ranges of mobility, indicating that key modifications necessary for streptostyly possibly appeared before the origin of crown lepidosaurs – and certainly before crown squamates. The importance of the Central European Basin for the origin of several reptile groups like archosauromorphs and turtles had already been demonstrated with iconic fossils like Protorosaurus and Pappochelys, but these new findings now include lepidosauromorphs, the second-most diverse group of amniotes, and highlight the importance of the systematic exploration of small taxa in Lagerstätten. https://zoobank.org/urn:lsid:zoobank.org:pub:95E38B1F-ADAD-4A8F-B45B-955FA7F3A196