Protorosaurus speneri (Seeley 1888) Late Permian ~260 mya, 2 m in length, was originally considered ancestral to lizards, but it is not related according to the present tree. Protorosaurus was derived from a sister to Prolacerta and was a sister to Boreopricea and Pamelaria.

Distinct from Prolacerta, the skull of Protorosaurus had larger nares and a shallower premaxilla. The jugal was more gracile. The nasals were longer and the frontals were shorter giving Protorosaurus a longer rostrum.

The cervicals were massive and slightly longer overall. The dorsal neural spines were taller. That tail had taller neural spines and shorter chevrons.

The scapula was concave anteriorly, losing the plate-like anterior rim found in Prolacerta. The forelimb was more robust with larger unguals.

The pelvis was shorter. The hind limbs was more robust and digit V was not so hook-like.

Czatkowiella harae (Borsuk−Biaynicka & Evans 2009) Early Triassic ~250 mya, was recently described as a long-necked sister to Protorosaurus, but if the scale bars are correct, Czatkowiellla had a more gracile neck that was not longer than that of other protorosaurs.

Distinct from Protorosaurus, the skull of Czatkowiella was longer, lower, flatter and wider. The maxilla ascended in a process just aft of the round naris. The jugal lacked a quadratojugal process. The desending process of the squamosal was gracile. The upper temporal fenestra was smaller. The lateral processes of the parietal were more posteriorly oriented.

The cervicals and dorsals were shallower with lower neural spines.

Evans SE and King MS 1993. A new specimen of Protorosaurus (Reptilia: Diapsida) from the Marl Slate (Late Permian) of Britain. Proceedings of the Yorkshire Geological Society 49, 229–234.

Gottmann−Quesada A and Sander PM 2009. A redescription of the early archosauromorph Protorosaurus speneri Meyer, 1832 and its phylogenetic relationships. Palaeontographica A 287, 123–220.

Borsuk−Biaynicka M and Evans S E 2009. A long−necked archosauromorph from the Early Triassic of Poland. Paleontologica Polonica 65: 203–234.

Seeley K 1888. Research on the structure, organisation and classification of the fossil Reptilia 1. On the Protorosaurus speneri (von Meyer). Philosophical Transactions of the Royal Society, London B 178, 187–213.

wiki/Protorosaurus

wiki/Czatkowiella