Parareptilia

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Parareptiles
Temporal range: Asselian - Rhaetian, 298.9–201.3 Ma
Bradysaurus im NHM Wien.JPG
Skeleton of a parareptile (Bradysaurus baini)
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Parareptilia
Olson, 1947
Orders

Parareptilia ("at the side of reptiles") is a subclass or clade of reptiles which is variously defined as an extinct group of primitive anapsids, or a more cladistically correct alternative to Anapsida. Whether the term is valid depends on the phylogenetic position of turtles, whose relationships to other reptilian groups are still uncertain.

History of classification[edit]

The name Parareptilia was coined by Olson in 1947 to refer to an extinct group of Paleozoic reptiles, as opposed to the rest of the reptiles or Eureptilia ("true reptiles").

Life restoration of Nyctiphruretus acudens

The name fell into disuse until it was revived by cladistic studies, to refer to those anapsids that were thought to be unrelated to turtles. Gauthier et al. 1988 provided the first phylogenetic definitions for the names of many amniote taxa and argued that captorhinids and turtles were sister groups, constituting the clade Anapsida (in a much more limited context than the definition given by Romer in 1967). A name had to be found for various Permian and Triassic reptiles no longer included in the anapsids, and "parareptiles" was chosen. However, they did not feel confident enough to erect Parareptilia as a formal taxon. Their cladogram was as follows:

Amniota 

SynapsidaRuskea rotta.png


 Sauropsida 
 "Parareptiles" 

MesosauridaeMesosaurus BW flipped.jpg




ProcolophonidaeRhipaeosaurusDB12 flipped.jpg




MillerettidaeMilleretta BW flipped.jpg




PareiasauriaScutosaurus BW flipped.jpg






 Reptilia 
 Anapsida 

CaptorhinidaeLabidosaurus flipped.jpg



TestudinesPsammobates geometricus 1872 white background.jpg



 Romeriida 

ProtorothyrididaeProtorothyris.jpg



DiapsidaZoology of Egypt (1898) (Varanus griseus).png






Laurin and Reisz 1995 found a different cladogram, in which Reptilia were divided into Parareptilia (now a formal taxon they defined as ‘‘Testudines and all amniotes more closely related to them than to diapsids.’’) and Eureptilia. Captorhinidae was transferred to Eureptilia, and Parareptilia included both early anapsid reptiles and turtles. The mesosaurs were placed outside both groups, as the sister group to the reptiles (but still sauropsids). The traditional group Anapsida was rejected as paraphyletic. This gave the following result:

Amniota 

SynapsidaRuskea rotta.png


 Sauropsida 

MesosauridaeMesosaurus BW flipped.jpg


 Reptilia 
 Parareptilia 

MillerettidaeMilleretta BW flipped.jpg


 Procolophonia 

PareiasauriaScutosaurus BW flipped.jpg


 Testudinomorpha 

ProcolophonidaeRhipaeosaurusDB12 flipped.jpg




TestudinesPsammobates geometricus 1872 white background.jpg






 Eureptilia 

CaptorhinidaeLabidosaurus flipped.jpg


Romeriida

ProtorothyrididaeProtorothyris.jpg



DiapsidaZoology of Egypt (1898) (Varanus griseus).png







In contrast, Rieppel, 1994, 1995; Rieppel & deBraga, 1996; and deBraga & Rieppel, 1997 argued that turtles are actually related to the sauropterygians, and are diapsids. The diapsid affinities of turtles have been supported by molecular phylogenies (e.g. Zardoya and Meyer 1998; Iwabe et al., 2004; Roos et al., 2007; Katsu et al., 2010). The first genome-wide phylogenetic analysis was completed by Wang et al. (2013). Using the draft genomes of Chelonia mydas and Pelodiscus sinensis, the team used the largest turtle data set to date in their analysis and concluded that turtles are likely a sister group of crocodilians and birds (Archosauria).[1] This placement within the diapsids suggests that the turtle lineage lost diapsid skull characteristics as it now possesses an anapsid skull. This would make Parareptilia a totally extinct group with skull features that coincidentally resemble those of turtles.

The cladogram below follows an analysis by M.S. Lee, in 2013.[2]

Amniota 

SynapsidaRuskea rotta.png


 Sauropsida 
 Parareptilia 

MillerettidaeMilleretta BW flipped.jpg




Eunotosaurus


 Hallucicrania 

LanthanosuchoideaLanthanosuchus NT flipped.jpg


Procolophonia

ProcolophonoideaRhipaeosaurusDB12 flipped.jpg



PareiasauromorphaScutosaurus BW flipped.jpg






 Eureptilia 

CaptorhinidaeLabidosaurus flipped.jpg


 Romeriida 

Paleothyris


 Diapsida 

AraeoscelidiaAraeoscelis.jpg


 Neodiapsida 

ClaudiosaurusClaudiosaurus white background.jpg




YounginiformesHovasaurus BW flipped.jpg




LepidosauromorphaZoology of Egypt (1898) (Varanus griseus).png


 Archosauromorpha 


ChoristoderaChampsosaurus BW flipped.jpg





TrilophosaurusTrilophosaurus buettneri (flipped).jpg



RhynchosauriaHyperodapedon BW2 white background.jpg




ArchosauriformesDescription des reptiles nouveaux, ou, Imparfaitement connus de la collection du Muséum d'histoire naturelle et remarques sur la classification et les caractères des reptiles (1852) (Crocodylus moreletii).jpg




 Sauropterygia 

EosauropterygiaDolichorhynchops BW flipped.jpg




PlacodontiaPsephoderma BW flipped.jpg




Sinosaurosphargis




Odontochelys




Proganochelys



TestudinesPsammobates geometricus 1872 white background.jpg
















References[edit]

  1. ^ Wang, Zhuo; Pascual-Anaya, J; Zadissa, A; Li, W; Niimura, Y; Huang, Z; Li, C; White, S; Xiong, Z; Fang, D; Wang, B; Ming, Y; Chen, Y; Zheng, Y; Kuraku, S; Pignatelli, M; Herrero, J; Beal, K; Nozawa, M; Li, Q; Wang, J; Zhang, H; Yu, L; Shigenobu, S; Wang, J; Liu, J; Flicek, P; Searle, S; Wang, J; et al. (27 March 2013). "The draft genomes of soft-shell turtle and green sea turtle yield insights into the development and evolution of the turtle-specific body plan". Nature Genetics. 45 (701–706): 701–6. PMC 4000948Freely accessible. PMID 23624526. doi:10.1038/ng.2615. Retrieved 15 November 2013. 
  2. ^ Lee, M. S. Y. (2013). "Turtle origins: Insights from phylogenetic retrofitting and molecular scaffolds". Journal of Evolutionary Biology. 26 (12): 2729–2738. PMID 24256520. doi:10.1111/jeb.12268. 
  • Katsu, Y.; Braun, E. L.; Guillette, L. J. Jr.; Iguchi, T.; Guillette (2010-03-17). "From reptilian phylogenomics to reptilian genomes: analyses of c-Jun and DJ-1 proto-oncogenes". Cytogenetic and Genome Research. 127 (2–4): 79–93. PMID 20234127. doi:10.1159/000297715. 

External links[edit]