Observations on the structure of the Early Permian reptile Stereosternum tumidum Cope

Simple item page
dc.contributor.authorModesto, Sean Patrick
dc.date.accessioned2015-01-12T07:53:12Z
dc.date.available2015-01-12T07:53:12Z
dc.date.issued1999
dc.description.abstractNew information on the mesosaur Stereosternum tumidum is derived from a nearly complete skeleton and other material. Two autapomorphies are identified for Stereosternum: (1) presence of an ‘odontoid’ axial process, formed probably by co-ossification of the atlantal pleurocentrum to that of the axis, and (2) the presence of a posterior supraneural process on the neural arch of dorsal vertebrae. Temporal fenestration appears to be absent in Stereosternum, marginal teeth are determined to be subcircular rather than oval in cross section and in this respect resemble those of Mesosaurus, and there is no sign of fracture planes in the caudal vertebrae that could be indicative of caudal autotomy. A phylogenetic analysis, based on a slightly modified data matrix from the literature, identifies Mesosauridae as the sister group of Parareptilia within the reptilian clade Anapsida (sensu lato). As a consequence of this rearrangement of amniote tree topology, the stem-based taxon Sauropsida is regarded to be in abeyance, because it now includes exactly the same taxa as Reptilia. Mesosaurs, at more than 275 million years of age, can be recognised as the oldest known anapsid reptiles.en_ZA
dc.description.sponsorshipThe Council's Research Committe, University of the Witwatersrand; National Science Foundationen_ZA
dc.identifier.issn0078-8554
dc.identifier.urihttp://hdl.handle.net/10539/16442
dc.language.isoenen_ZA
dc.publisherBernard Price Institute for Palaeontological Researchen_ZA
dc.subjectstereosternumen_ZA
dc.subjectmesosaursen_ZA
dc.subjectAnapsidaen_ZA
dc.subjectphylogenyen_ZA
dc.subjectpermianen_ZA
dc.titleObservations on the structure of the Early Permian reptile Stereosternum tumidum Copeen_ZA
dc.typeArticleen_ZA
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
1999.V35.MODESTO.STRUCTURE OF STEREOSTERNUM TUMIDUM.pdf
Size:
1.84 MB
Format:
Adobe Portable Document Format
Download
License bundle
Now showing 1 - 1 of 1
No Thumbnail Available
Name:
license.txt
Size:
1.71 KB
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Volume 35 1999