A fourth Protorothyris specimen described as a µCT scan

Jenkins, Behlke and Sues 2025 applied
“µCT imaging to a previously undescribed specimen of Protorothyris archeri. Our segmentations revealed previously unknown anatomical details of this species, including enlarged dentary teeth, denticles on the parabasisphenoid, and the morphology of the internal surfaces of the dermatocranial elements. We included this specimen within a phylogenetic matrix of 177 operational taxonomic units and 628 morphological characters designed to examine the relationships of early-diverging amniotes, particularly stem reptiles. Bayesian and parsimony analyses reveal that there is still topological discordance among some clades (e.g. caseasaurs, varanopids), although these analyses confirm that ‘protorothyridids’ do not form a clade, consistent with other recent phylogenetic analyses.”

This new dorsoventrally crushed skull specimen,
UNSM PAL382180, was added to the large reptile tree (LRT, 2340 taxa) as the fourth Protorothyris tested. There is no topological discordance among clades in the LRT.

IMHO each of the four specimens
should be considered a separate species based on bone suture patterns and skull proportions. Only one, CM 8617, has been assigned to its own species, P. morani.

Please click on the above links to see images. My OS is now incompatible with WP and I am unable to upgrade probably due to that. I am also unable to upload images at present. Apologies.

The authors reported,
“We conducted phylogenetic analyses in both parsimony and Bayesian frameworks, and Seymouria baylorensis was chosen as the outgroup in both instances. We coded character, clock, and tree models after Sim~oes et al. (2022), which hypothesize a root age for the origin of amniotes to be 315–330 Ma (=mya) which is consistent with the known fossil record (Carroll & Baird 1972; Tuinen & Hadley 2004) and estimates from genomic datasets.”

The LRT narrows the origin of amniotes
= reptiles to Silvanerpeton as a last common ancestor in the Viséan 330–346 mya. A long list of basal reptiles, including Silvanerpeton, do not appear in the cladogram of Jenkins, Behlke and Sues (their figure 8). That list can be found in the LRT. Rather an invalidated arrangement is presented that nests dissimilar caseasaurs with synapsids, mesosaurs with millerettids and rib-gliders, like Weigeltisaurus, with aquatic taxa ike Claudiosaurus and Tangasaurus. These mistakes arise from borrowed cladograms borrowing from borrowed cladograms. More taxa are needed. See the LRT for a list.

To their credit,
the authors added 27 new taxa to their borrowed cladogram, but those were unable to provide the first dichotomy within the Reptilia, the one splitting Lepidosauromorpha from Archosauromorpha (link below), nor were they able to recover two separate origins for the diapsid skull morphology (link below).

https://pterosaurheresies.wordpress.com/2016/06/14/when-synapsids-and-diapsids-split/

https://pterosaurheresies.wordpress.com/2011/07/31/the-big-kahuna-the-reptilia-is-diphyletic/

References
Clark J and Carroll RL 1973. Romeriid Reptiles from the Lower Permian. Bulletin of the Museum of Comparative Zoology 144 (5): 353-408.
Jenkins KM, Behlke ADB and Sues H-D 2025. New anatomical details concerning the cranial structure of the early Permian stem reptile Protorothyris archeri revealed by µCT, with implications for the evolution of olfaction in reptiles. Palaeontology 68(6): e70038.
Price LI 1937. Two new Cotylosaurs from the Permian of Texas: Proceedings of the New England Zoological Club, v. 16, p. 97-102.

wiki/Protorothyris