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.
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 contains | Matrices |
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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
MorphoBank Project 727
- Creation Date:
30 April 2012 - Publication Date:
01 May 2012 - Project views: 36802
- Media downloads: 43
- Matrix downloads: 11
Authors' Institutions
- University of the Witwatersrand
- University of Washington
Members
member name | taxa ![]() |
specimens ![]() |
media ![]() | chars ![]() | character
| cell scorings (scored, NPA, "-") | cell
| rules ![]() | ||||||
MorphoBank Curator Project Administrator | 16 | 1 | 2 | 56 | 0 | 0 | 726 (726, 0, 0) | 0 | 0 | 0 | ||||
Maureen Admin Full membership ![]() | 0 | 0 | 0 | 0 | 0 | 0 | 0 (0, 0, 0) | 0 | 0 | 0 | ||||
Christian Sidor Full membership ![]() | 0 | 0 | 2 | 0 | 0 | 0 | 0 (0, 0, 0) | 0 | 0 | 0 |
Taxonomic Overview for Matrix 'M1643' (15 Taxa)
taxon | unscored cells |
scored cells ![]() |
no cell support ![]() |
NPA cells |
"-" cells | cell images | labels on cell images |
member access |
[1] Haptodus Last Modified in 12/05/13 | 3 | 53 | 53 | 0 | 0 | 0 | 0 | 3 ![]() |
[2] Dimetrodon Last Modified in 12/05/13 | 1 | 55 | 55 | 0 | 0 | 0 | 0 | 3 ![]() |
[3] Patranomodon Last Modified in 12/05/13 | 6 | 50 | 50 | 0 | 0 | 0 | 0 | 3 ![]() |
[4] Suminia Last Modified in 12/05/13 | 4 | 52 | 52 | 0 | 0 | 0 | 0 | 3 ![]() |
[5] Syodon Last Modified in 12/05/13 | 1 | 55 | 55 | 0 | 0 | 0 | 0 | 3 ![]() |
[6] Titanophoneus Last Modified in 12/05/13 | 1 | 55 | 55 | 0 | 0 | 0 | 0 | 3 ![]() |
[7] Titanosuchidae Last Modified in 12/05/13 | 2 | 54 | 54 | 0 | 0 | 0 | 0 | 3 ![]() |
[8] Estemmenosuchus Last Modified in 12/05/13 | 10 | 46 | 46 | 0 | 0 | 0 | 0 | 3 ![]() |
[9] Biarmosuchus Last Modified in 12/05/13 | 8 | 48 | 48 | 0 | 0 | 0 | 0 | 3 ![]() |
[10] Hipposaurus (cgp) Last Modified in 12/05/13 | 6 | 51 | 50 | 0 | 0 | 0 | 0 | 3 ![]() |
[11] Lycaenodon (both) Last Modified in 12/05/13 | 22 | 34 | 34 | 0 | 0 | 0 | 0 | 3 ![]() |
[12] Herpetoskylax (cgp) Last Modified in 12/05/13 | 3 | 55 | 53 | 0 | 0 | 0 | 0 | 3 ![]() |
[13] Ictidorhinus Last Modified in 12/05/13 | 31 | 25 | 25 | 0 | 0 | 0 | 0 | 3 ![]() |
[14] Lobalopex Last Modified in 12/05/13 | 8 | 48 | 48 | 0 | 0 | 0 | 0 | 3 ![]() |
[15] Lemurosaurus (nm) Last Modified in 12/05/13 | 11 | 45 | 45 | 0 | 0 | 0 | 0 | 3 ![]() |
Project views 
type | number of views | Individual items viewed (where applicable) |
Total project views | 36802 | |
Project overview | 4855 | |
Media views | 9831 | Media search (5497 views); M107722 (1468 views); M107720 (1035 views); M107724 (833 views); M107723 (998 views); |
Matrix views | 2605 | Matrix landing page (2273 views); Herpetoskylax Matrix (332 views); |
Specimen list | 3430 | |
Taxon list | 12795 | |
Bibliography | 1324 | |
Documents list | 1962 |
Project downloads 
type | number of downloads | Individual items downloaded (where applicable) |
Total downloads from project | 469 | |
Media downloads | 43 | M107722 (21 downloads); M107724 (8 downloads); M107720 (8 downloads); M107723 (6 downloads); |
Project downloads | 409 | |
Matrix downloads | 11 | Herpetoskylax Matrix (11 downloads); |
Document downloads | 6 | Character List (4 downloads); Copyright information for exemplar media (2 downloads); |