Romeriida

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Romeriidans
Temporal range: Pennsylvanian to Recent, 311.3–0Ma
Paleothyris BACKGROUND.JPG
Paleothyris acadiana, an early romeriidan
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Eureptilia
Clade: Romeriida
Gauthier et al., 1988
Subgroups

Paleothyris
Diapsida

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]

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 of 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[edit]

  1. ^ a b c Laurin, M.; and 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.; and 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. ^ a b Müller, J.; and 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[edit]