Romeriida

Romeriida is a clade of reptiles that consists of diapsids and the extinct protorothyridid genus Paleothyris, if not the entire family Protorothyrididae. It is phylogenetically defined by Laurin & Reisz (1995) as the last common ancestor of Paleothyris and diapsids, and all its descendants.[1] It is named after Alfred Romer, a prominent vertebrate paleontologist of the twentieth century.[2]

Romeriidans Temporal range: Pennsylvanian–Present, 312–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Central bearded dragon (Pogona vitticeps)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Eureptilia
Clade:	Romeriida Gauthier et al., 1988
Subgroups
†Hylonomus †Paleothyris †Protorothyrididae Diapsida †Araeoscelidia Neodiapsida various extinct clades Sauria

Protorothyridids were once placed in the family Romeriidae along with the captorhinid Romeria.[1] Because Romeria is now considered to be a captorhinid, and Captorhinidae is placed outside Romeriida, the genus is excluded from the clade. Protorothyridids were once the collective term for several romeriid genera of uncertain classification. However, more recent studies have proposed that Protorothyrididae is a paraphyletic taxon.[3] Therefore, it is possible that many protorothyridids do not lie within the clade Romeriida.

Several synapomorphies characterize the romeriids. These include the separation of the tabular bone from the opisthotic bone, ventrally keeled anterior pleurocentra, long and slender carpi and tarsi, and overlapping metapodials.[1]

Below is a cladogram showing the placement of Romeriida within Amniota, modified from Hill, 2005:[4]

Amniota	Mesosauridae       Synapsida    Reptilia    Parareptilia    Eureptilia    Captorhinidae    Romeriida   Paleothyris acadiana     Diapsida

Cladogram after Müller & Reisz, 2006:[3]

Amniota	Synapsida   Reptilia   Parareptilia (including Mesosauridae)    Eureptilia    Coelostegus         Thuringothyris     Captorhinidae         Brouffia    Romeriida   Paleothyris       Hylonomus      Protorothyrididae   Anthracodromeus     Cephalerpeton     Protorothyris       Diapsida

   Polyphyletic Protorothyrididae

References

1. Laurin, M.; Reisz, R. (1995). "A reevaluation of early amniote phylogeny". Zoological Journal of the Linnean Society. 113 (2): 165–223. doi:10.1111/j.1096-3642.1995.tb00932.x.
2. Gauthier, J. A.; Kluge, A. G.; Rowe, T. (1988). "The early evolution of the Amniota". In M. J. Benton (ed.). The Phylogeny and Classification of the Tetrapods, Volume 1: Amphibians, Reptiles, Birds. Systematics Association Special Volume. 35A. Clarendon Press. pp. 103–155.
3. Müller, J.; Reisz, R. R. (2006). "The phylogeny of early eureptiles: comparing parsimony and Bayesian approaches in the investigation of a basal fossil clade". Systematic Biology. 55 (3): 503–511. doi:10.1080/10635150600755396. PMID 16861212.
4. Hill, R. V. (2005). "Integration of morphological data sets for phylogenetic analysis of Amniota: the importance of integumentary characters and increased taxonomic sampling". Systematic Biology. 54 (4): 530–547. doi:10.1080/10635150590950326. PMID 16085573.

External links

• Romeriida in the Paleobiology Database