Youngina and Youngoides are key fossil taxa in the ancestry of the Archosauriformes according to the large reptile tree. Derived from Prolacerta and the real Prolacertiformes (not including Tanystropheus, Macrocnemus, etc.), this clade of small unspecialized reptiles is known from several specimens, some found grouped together en masse.
To my knowledge, not since Gow 1975 has there been a comprehensive look at the Youngina clade, and that one could have been more detailed. If so, that means we haven’t seen a phylogenetic analysis of this clade and their place in the reptile panoply. The Youngina clade includes a variety of morphologies, which some have attributed to crushing. This is worth testing because the differences may have some phylogenetic value.
As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.
Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.
Broom R 1914. A new thecodont reptile. Proceedings of the Zoological Society of London, 1914:1072-1077.
Gardner NM, Holliday CM and O’Keefe FR 2010. The braincase of Youngina capensis(Reptilia, Diapsida): New insights from high-resolution CT scanning of the holotype. Paleonotologica Electronica 13(3):online PDF
Gow CE 1975. The morphology and relationships of Youngina capensis Broom and Prolacerta broomi Parrington. Palaeontologia Africana, 18:89-131.
Olsen EC 1936. Notes on the skull of Youngina capensis Broom. Journal of Geology, 44 (4): 523-533.
Reisz RR, Modesto SP and Scot DMT 2011. A new Early Permian reptile and its significance in early diapsid evolution. Proceedings of the Royal Society, London B