The oldest known rhynchocephalian reptile from the Middle Triassic (Ladinian) of Germany and its phylogenetic position among Lepidosauromorpha

Abstract

Skeletal remains of a small lepidosaurian reptile from the Middle Triassic (Ladinian: Longobardian) Erfurt Formation, exposed in a commercial limestone quarry near Vellberg (Germany), represent the oldest rhynchocephalian known to date. The new taxon, Wirtembergia hauboldae, is diagnosed by the following combination of features: Premaxilla with four teeth, first being largest and decreasing in size from first to fourth. Jugal with tiny, spur‐like posterior process. Lateral surface of dentary strongly convex dorsoventrally for much of length of bone, bearing distinct longitudinal ridge and sculpturing in large specimens. Coronoid eminence of dentary low, subrectangular, and with dorsoventrally concave lateral surface in larger specimens. Dentition with pleurodont anterior and acrodont posterior teeth. Posterior (=additional) teeth with (in side view) triangular, at mid‐crown level labiolingually somewhat flattened crowns, and with oval bases. Phylogenetic analysis recovered the new rhynchocephalian as the earliest‐diverging member of its clade known to date.

A new sphenodontian (Diapsida: Lepidosauria) from the Upper Triassic (Norian) of Germany and its implications for the mode of sphenodontian evolution

“…2 A, S 3 -S 6 ). Like in [ 19 ], Gephyrosaurus bridensis was recovered as a basal rhynchocephalian in our analysis, although it was found outside Rhynchocephalia in some topologies published by [ 23 ]. Despite their overall resemblance, Parvosaurus harudensis and Diphydontosaurus avonis do not cluster together as sister taxa in any tree topology recovered in this study (Supplementary Fig.…”

“…Their disparity also manifested in their body size variation, which ranged over one order of magnitude [ 7 ]. Most of this disparity is contained within Sphenodontia (= ”Sphenodontida” sensu [ 18 ] and as applied in [ 19 ], all rhynchocephalians more closely related to Sphenodon punctatus than Gephyrosaurus bridensis ). Although they were a dominant component of the Mesozoic fauna, Laurasian sphenodontian diversity and abundance rapidly decreased during the Early Cretaceous [ 10 , 20 ], possibly due to the changing climate during the fragmentation of Pangea in this period [ 16 ].…”

“…While some studies yielded a steady decrease in change rates throughout Sphenodontia [ 23 ], or decreasing, but more heterogeneous rates within the clade and higher rates on terminal than internal branches [ 24 ], an approach focusing on body size evolutionary rates [ 21 ] revealed increasing rates within Mesozoic Sphenodontia throughout time. Many sphenodontians have been discovered in the Triassic and Jurassic formations of Germany, including Polysphenodon muelleri [ 25 , 26 ], Oenosaurus muehlheimensis [ 16 ], Vadasaurus herzogi [ 27 ], and Palaeopleurosaurus posidoniae [ 26 ], as well as the basal rhynchocephalian Wirtembergia hauboldae [ 19 ]. The steady increase in information on early sphenodontians is a valuable resource for understanding the evolutionary dynamics of the clade and might offer new insights into the evolutionary rates within it.…”

The dawn of an Era: New contributions on comparative and functional anatomy of Triassic tetrapods

“…As Dr. Hans‐Dieter Sues aptly emphasized in his introductory comment to this special edition Sues (2024, this issue), the significance of all these contributions shows that we are indeed experiencing a “golden age” of Triassic vertebrate research. Perhaps never before has this crucial temporal interval attracted such widespread interest from researchers of many generations and parts of the world.…”

“…In a world where all continents were united, in a land dominated by hot climates and expansive deserts at its core—while boasting diverse environments along its peripheries—life resiliently endured and even flourished amid several events of climatic changes. Many vertebrate lineages populating current ecosystems, such as birds, testudines, lizards, crocodiles, and mammals, can trace their origins or early diversification events back to the Triassic period (e.g., Dal Corso et al, 2020; Simões et al, 2018; Sues, 2024), and significant events of adaptive radiation were able to forge an unprecedented diversity of body plans and lifestyles during this period (Araújo et al, 2022; Benton & Wu, 2022). Besides (or even explained by) its macroevolutionary significance, the Triassic period is a fertile field of scientific research, and growing attention has been devoted to Triassic tetrapods, whether from an anatomical, ecological, or evolutionary perspective.…”