Wirtembergia

Wirtembergia is an extinct genus of rhynchocephalian reptile known from the Middle Triassic (Ladinian) of Germany. It is the earliest known rhynchocephalian.

History of discovery
The first remains of the genus were reported in 2013 as cf. Diphydontosaurus based on two lower jaws found in the Middle Triassic (Ladinian) Erfurt Formation, located in the state of Baden-Württemberg near the settlement of Vellberg. In 2023, the genus and species Wirtembergia hauboldae was described based on this material, as well as a partial skeleton (SMNS 91313) found at the same locality, including parts of the skull (the premaxilla, maxilla, jugal, frontal, pterygoid, and a possible partial palatine) as well as limb bones and ribs.

Description
The skull when complete is estimated to have been around 2-2.5 cm long, with an estimated total body length of around 20-25 cm. The jaws have a combination of slightly backward curving (recurved) column-like pleurodont front teeth attached to the inner side of the jaw along with larger posterior triangular acrodont teeth attached to the apex of the jaw bone, similar to other primitive rhynchocephalians like Diphydontosaurus. These teeth underwent replacement. The frontal bones of the skull were not fused to each other, unlike other known rhynchocephalians, though this may have been present in more ontogenically mature individuals.

Phylogeny
Wirtembergia has been placed as the most basal rhynchocephalian: