Araeoscelidia

Araeoscelidans Temporal range:Carboniferous–Permian
Life restoration (top) and skull reconstruction (bottom) ofPetrolacosaurus kansensis
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Diapsida
Order:	†Araeoscelidia Williston,1913
Genera
†Spinoaequalis †Petrolacosaurus †Zarcasaurus †Araeoscelis †Aphelosaurus †Kadaliosaurus †Halgaitosaurus

AraeoscelidiaorAraeoscelidais acladeof extinctamniotes(traditionally classified asdiapsidreptiles) superficially resemblinglizards,extending from the LateCarboniferousto the EarlyPermian. The group contains thegeneraAraeoscelis,Petrolacosaurus,the possibly aquaticSpinoaequalis,and less well-known genera such asKadaliosaurusandZarcasaurus.This clade is usually considered to be thesister groupto all (currently known) later diapsids.

Description

Araeoscelidians were small animals (less than one meter in length) looking somewhat like lizards, though they are only distantly related to true lizards. They differ from other, earliersauropsidsby their slender limbs, their elongated tail, and of course by the presence of twotemporal openings,the feature defining thediapsidcondition. InAraeoscelis,only the upper temporal opening remains, thus resulting in a derivedeuryapsidcondition.

Genera

Araeoscelidia includes well-known genera such asAraeoscelisWilliston 1910,PetrolacosaurusLane 1945andSpinoaequalis,known from virtually complete skeletons.Zarcasaurus,AphelosaurusandKadaliosaurusbelong to this clade but are known only from post-cranial remains and a mandible fragment forZarcasaurus.

The genusDictyboloshas been included in Araeoscelidia by Olson (1970)but this inclusion has been criticized e.g., by Evans (1988),especially since Olson also included distantly related groups such asprotorosaursandmesosaurs.

New specimens have been discovered in the United States state ofOklahoma,but lack a scientific description as of 2023.

Phylogeny

The majority of phylogenetic studies recover araeoscelidians as the mostbasalgroup of diapsids; however, Simõeset al.(2022) recover them asstem-amniotesinstead, as the sister group to the clade includingCaptorhinidaeandProtorothyrisarcheri.

Stratigraphic and geographic distribution

Araeoscelidia are known from the Late Carboniferous in the United States (Petrolacosaurus,Spinoaequalis) to the Early Permian in France (Aphelosaurus), Germany (Kadaliosaurus) and the United States (Dictybolos,Zarcasaurus,Araeoscelis, Halgaitosaurus). Apart from araeoscelidans, only one other diapsid is known before theLate Permian:Orovenatorfrom the Early Permian of Oklahoma.

Further reading

• Carroll, Robert L. (1988).Vertebrate Paleontology and Evolution.New York: W.H. Freeman and Co.ISBN0-7167-1822-7.
• Benton, Michael J.(2000).Vertebrate Paleontology(2nd ed.). Oxford: Blackwell Science.ISBN0-632-05614-2.
• deBraga, M. & Reisz, R. R. (1995). "A new diapsid reptile from the uppermost Carboniferous (Stephanian) of Kansas".Palaeontology.38:199–212.
• deBraga, M. & Rieppel, O. (1997)."Reptile phylogeny and the interrelationships of turtles".Zoological Journal of the Linnean Society.120(3): 281–354.doi:10.1111/j.1096-3642.1997.tb01280.x.
• Brinkman, D. B.; Berman, D. S. & Eberth, D. Z. (1984)."A new araeoscelid reptile,Zarcasaurus tandyderus,from the Culter Formation, (Lower Permian) of north-central New Mexico "(PDF).New Mexico Geology.6(2): 34–39.
• Credner, H. (1889). "Die Stegocephalen und Saurier aus dem Rothliegenden des Plauen'schen Grundes bei Dresden. 8 –Kadaliosaurus priscusCred ".Zeitschrift der Deutschen Geologischen Gesellschaft.41:319–342.
• Evans, S. E. (1988). "The early history and relationships of the Diapsida". In Benton, M. J. (ed.).The phylogeny and classification of the tetrapods.Vol. 1: Amphibians, Reptiles, Birds.Systematics Association Special Volume35 A. Oxford: Clarendon Press. pp. 221–260.ISBN0-19-857705-2.
• Falconnet, J. & Steyer, J.-S. (2007). "Revision, osteology and locomotion ofAphelosaurus,an enigmatic reptile from the Lower Permian of France ".Journal of Morphology(abstract of the 8th International Congress of Vertebrate Morphology, Paris, July 2007): 38.
• Gervais, P.(1859).Zoologie et paléontologie française(2nd ed.). Paris: Bertrand.
• Laurin, M.(1991). "The osteology of a Lower Permian eosuchian from Texas and a review of a diapsid phylogeny".Zoological Journal of the Linnean Society.101:59–95.doi:10.1111/j.1096-3642.1991.tb00886.x.
• May, W. J. & Hall, J. D. (2002). "Geology and vertebrate fauna of a new site in the Wellington Formation (Lower Permian) of Northern Oklahoma".Oklahoma Geology Notes.62(2): 63–66.
• Olson, E. C. (1970). "New and little known genera and species of vertebrates from the Lower Permian of Oklahoma".Fieldiana: Geology.18:359–434.
• Peabody, F. E. (1952). "Petrolacosaurus kansensisLane, a Pennsylvanian reptile from Kansas ".University of Kansas Paleontological Contributions.10:1–41.hdl:1808/3785.
• Reisz, R. R. (1981)."A diapsid reptile from the Pennsylvanian of Kansas".Special Publication of the Museum of Natural History, University of Kansas.7:1–74.
• Reisz, R. R.; Berman, D. S. & Scott, D. (1984). "The anatomy and relationships of the Lower Permian reptileAraeoscelis".Journal of Vertebrate Paleontology.4(1): 57–67.doi:10.1080/02724634.1984.10011986.
• Reisz, Robert R.; Modesto, Sean P.; Scott, Diane M. (2011)."A new Early Permian reptile and its significance in early diapsid evolution".Proceedings of the Royal Society B.278(1725): 3731–3737.doi:10.1098/rspb.2011.0439.PMC3203498.PMID21525061.
• Swanson, B. A. & Carlson, K. J. (2002)."Walk, Wade, or Swim? Vertebrate Traces on an Early Permian Lakeshore"(PDF).PALAIOS.17(2): 123–133.Bibcode:2002Palai..17..123S.doi:10.1669/0883-1351(2002)017<0123:WWOSVT>2.0.CO;2.S2CID130593903.
• Thévenin, A. (1910). "Les plus anciens quadrupèdes de France".Annales de Paléontologie.5:1–65.
• Vaughn, P. P. (1955). "The Permian reptileAraeoscelisrestudied ".Bulletin of the Harvard Museum of Comparative Zoology.113:305–467.