Temporal range: Pennsylvanian–Recent, Possible Bashkirian records.
Edaphosaurus pogonias skeleton mounted at the Field Museum.
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Synapsida
Clade: Eupelycosauria
Kemp, 1982

Eupelycosauria is a large clade of animals characterized by the unique shape of their skull, encompassing all mammals and their closest extinct relatives. They first appeared 308 million years ago during the Early Pennsylvanian epoch, with the fossils of Echinerpeton and perhaps an even earlier genus, Protoclepsydrops, representing just one of the many stages in the evolution of mammals,[3] in contrast to their earlier amniote ancestors.

Eupelycosaurs are synapsids, animals whose skull has a single opening behind the eye. They are distinguished from the Caseasaurian synapsids by having a long, narrow supratemporal bone (instead of one that is as wide as it is long) and a frontal bone with a wider connection to the upper margin of the orbit.[4] The only living descendants of basal eupelycosaurs are the mammals.

The group was originally considered a suborder of pelycosaurs or "mammal like reptiles",[5] but it was redefined in 1997, and the term pelycosaur itself has fallen into disfavor. We now know that the eupelycosaurs were not in fact reptiles nor of reptile lineage - the modern term stem mammal is used instead. Some recent studies suggested that one of its subgroups, Varanopidae, are really nested within sauropsids,[6][7][8] leaving the other defined subgroup of it, Metopophora, as its synonym.

  1. ^ a b Spindler, F., R. Wernburg, J. W. Schneider, L. Luthardt, V. Annacker, and R. Roßler. 2018. First arboreal ‘pelycosaurs’(Synapsida:Varanopidae) from the early Permian Chemnitz Fossil Lagerstatte, SE-Germany, with a review of varanopid phylogeny. Palaontologische Zeitschrift. doi: 10.1007/s12542-018-0405-9.
  2. ^ Neil Brocklehurst & Jörg Fröbisch (2018) A reexamination of Milosaurus mccordi, and the evolution of large body size in Carboniferous synapsids, Journal of Vertebrate Paleontology, 38:5, DOI: 10.1080/02724634.2018.1508026
  3. ^ Kemp. T.S., 1982, Mammal-like Reptiles and the Origin of Mammals. Academic Press, New York
  4. ^ Laurin, M. and Reisz, R. R., 1997, Autapomorphies of the main clades of synapsids - Tree of Life Web Project
  5. ^ Reisz, R. R., 1986, Handbuch der Paläoherpetologie – Encyclopedia of Paleoherpetology, Part 17A Pelycosauria Verlag Dr. Friedrich Pfeil, ISBN 3-89937-032-5
  6. ^ Ford, David P.; Benson, Roger B. J. (2018). "A redescription of Orovenator mayorum (Sauropsida, Diapsida) using high‐resolution μCT, and the consequences for early amniote phylogeny". Papers in Palaeontology. 5 (2): 197–239. doi:10.1002/spp2.1236.
  7. ^ Modesto, Sean P. (January 2020). "Rooting about reptile relationships". Nature Ecology & Evolution. 4 (1): 10–11. doi:10.1038/s41559-019-1074-0. ISSN 2397-334X. PMID 31900449. S2CID 209672518.
  8. ^ MacDougall, Mark J.; Modesto, Sean P.; Brocklehurst, Neil; Verrière, Antoine; Reisz, Robert R.; Fröbisch, Jörg (2018). "Commentary: A Reassessment of the Taxonomic Position of Mesosaurs, and a Surprising Phylogeny of Early Amniotes". Frontiers in Earth Science. 6. doi:10.3389/feart.2018.00099. ISSN 2296-6463.

Powered by 654 easy search