Project 727: C. A. Sidor,B. S. Rubidge. 2006. Herpetoskylax hopsoni, a New Biarmosuchian (Therapsida: Biarmosuchia) from the Beaufort Group of South Africa. Amniote Paleobiology: Perspectives on the Evolution of Mammals, Birds, and Reptiles. (ISBN: 9780226094779):76-113.
Specimen: Herpetoskylax hopsoni (CGP/1:67)

Abstract

A new genus and species of biarmosuchian therapsid, Herpetoskylax hopsoni, is described on the basis of a well preserved skull and lower jaws from the rocks of the Cistecephalus Assemblage Zone (Upper Permian) of the Beaufort West District of South Africa. Autapomorphies of Herpetoskylax include the lack of a distinct fossa on the posterior surface of the squamosal, the degree to which the zygomatic arch appears elevated in lateral view, and the large size of the quadratojugal foramen and post-temporal fenestrae.
We review recent work on biarmosuchian systematics and taxonomy. Rubidgina angusticeps is found to be based on an undiagnostic holotype and declared a nomen dubium. A specimen previously referred to Rubidgina is instead referable to Herpetoskylax. We re-evaluate previously proposed biarmosuchian synapomorphies and provide a revised cladistic analysis of the group. Our analysis includes 13 ingroup taxa (four dinocephalians, two anomodonts, seven biarmosuchians) and 56 characters of the skull, lower jaw, and dentition. A strict consensus of nine minimum length trees suggests that Dinocephalia, Anomodontia, and Biarmosuchia (minus Biarmosuchus) are monophyletic taxa. Relationships among these clades are incompletely resolved, but in most trees biarmosuchians form a clade that is the sister taxon to Anomodontia, with Dinocephalia positioned as the most primitive therapsid clade. Within Biarmosuchia, Hipposaurus and (variably) Biarmosuchus represent the two most primitive forms. Herpetoskylax, along with Lycaenodon and Ictidorhinus, is positioned between these two taxa and the derived biarmosuchian subclade, Burnetiamorpha.


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Project DOI: 10.7934/P727, http://dx.doi.org/10.7934/P727
This project containsMatrices
  • 4 Media
  • 1 Matrix
  • 2 Documents
  • 16 Taxa
  • 1 Specimen
  • 56 Characters
Total size of project's media files: 6 MB

Download Project SDD File
Total scored cells: 726
Total media associated with cells: 0
Total labels associated with cell media: 0
Characters
Total characters: 56
Total characters with associated media: 0
Total characters with media with labels: 0
Total character states: 122
Total character states with associated media: 0
Total character states with media with labels:0
Total unordered/ordered characters:56/0
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MorphoBank Project 727


    Members

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    MorphoBank Curator
    Project Administrator
    Last logged in 05/01/12
    16125600726
    (726, 0, 0)
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    Maureen Admin
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    Christian Sidor
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    Last logged in 05/01/12
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    Taxonomic Overview for Matrix 'M1643' (15 Taxa)

    taxon unscored
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    "-" cellscell images labels on
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    [1] Haptodus
    Last Modified in 12/05/13
    3535300003
    [2] Dimetrodon
    Last Modified in 12/05/13
    1555500003
    [3] Patranomodon
    Last Modified in 12/05/13
    6505000003
    [4] Suminia
    Last Modified in 12/05/13
    4525200003
    [5] Syodon
    Last Modified in 12/05/13
    1555500003
    [6] Titanophoneus
    Last Modified in 12/05/13
    1555500003
    [7] Titanosuchidae
    Last Modified in 12/05/13
    2545400003
    [8] Estemmenosuchus
    Last Modified in 12/05/13
    10464600003
    [9] Biarmosuchus
    Last Modified in 12/05/13
    8484800003
    [10] Hipposaurus (cgp)
    Last Modified in 12/05/13
    6515000003
    [11] Lycaenodon (both)
    Last Modified in 12/05/13
    22343400003
    [12] Herpetoskylax (cgp)
    Last Modified in 12/05/13
    3555300003
    [13] Ictidorhinus
    Last Modified in 12/05/13
    31252500003
    [14] Lobalopex
    Last Modified in 12/05/13
    8484800003
    [15] Lemurosaurus (nm)
    Last Modified in 12/05/13
    11454500003


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    Total project views20275
    Project overview2833
    Media views5877Media search (3263 views); M107722 (968 views); M107720 (619 views); M107724 (441 views); M107723 (586 views);
    Matrix views1597Matrix landing page (1415 views); Herpetoskylax Matrix (182 views);
    Specimen list1998
    Taxon list5887
    Bibliography763
    Documents list1320




    Project downloads

    type number of downloads Individual items downloaded (where applicable)
    Total downloads from project228
    Media downloads25M107722 (13 downloads); M107724 (4 downloads); M107720 (5 downloads); M107723 (3 downloads);
    Project downloads187
    Matrix downloads10Herpetoskylax Matrix (10 downloads);
    Document downloads6Character List (4 downloads); Copyright information for exemplar media (2 downloads);