Bullacephalus: Difference between revisions

Introductory/Overview and Etymology-

Bullacephalus is a genus of theraspida that lived during the Late Permian period, approximately 250 million years ago. The name Bullacephalus comes from the Latin words "bullatus," meaning "bossed" or "knobbed," and "cephalus," meaning "head." This name refers to the distinctive bony knob on the top of the theraspid's skull, which contributes to the history of this genus. This stem based taxon includes Ictidorhinus or Hippasaurs. Bullacephalus can even be characterized as having a, “skull moderately to greatly pachyostotic; swollen boss present above the postorbital bar formed by the postfrontal and postorbital; deep linear sculpturing of the snout; exclusion of the jugal from the lateral temporal fenestra” (Day et al., 2016). These Therapsids have spongy bone skull roof, palatal process of premaxilla are long, diverticulum of naris adding them to the Burnetiamorph.

Geological/Paleoenvironmental Information and Historical Information and Discovery-

This species is known from a complete skull and lower jaw that was discovered during the fieldwork of the Lower Beaufort group in the southern Karoo of South Africa. The Beaufort Group rocks in South Africa are well-known for their abundant Permo-Triassic therapsid fossils, which have allowed for biostratigraphic subdivision of the group into eight assemblage zones. In 1993, during fieldwork for biostratigraphic research in the lower Beaufort Tapinocephalus Assemblage Zone, a well-preserved skull of a medium-sized therapsid was discovered. The skull shares similarities with representatives of the Burnetiidae, a clade of basal therapsids that has only two known genera, Burnetia and Proburnetia, each represented by only one specimen. The newly discovered skull provides important new information about this enigmatic group of therapsids and their phylogenetic position within the Therapsida.(BRUCE S. RUBIDGE and JAMES W. KITCHING)

Taxobox- Despite the limited amount of fossil material available, Bullacephalus has generated considerable interest among paleontologists due to its unique morphology and uncertain taxonomic classification. It is apart of the Burnetiamorpha suborder. Currently, the Burnetiamorpha comprise nine genera: Bullacephalus, Burnetia, Lemurosaurus, Lobalopex, Lophorhinus, Paraburnetia, and Pachydectes from South Africa. (Kruger et al., 2015). Some researchers have suggested that Bullacephalus are a type of Theraspida: Biarmoschia, related to the successful tetrapod Anomadontiahelping researchers understand the basic morphology. This specific theraspid could be distinguished by the short snout, septomaxilla, and has a short facial exposure between nasal and maxilla, along with many other skull characteristics.

• Kingdom: Animalia
• Phylum: Chordata
• Clade: Theraspida
• Suborder: Biarmosuchia
• Family: Burnetiidae
• Genus: Bullacephalus
• Species: Bullacephalus wildi

Description and Paleobiology-

The specimen of Bullacephalus is a moderately complete skull and lower jaw, with some missing anterior portions of the snout and lower jaw and badly weathered left side and skull roof posterior to the pineal foramen. The temporal opening is situated posteroventral to the orbit, and three pachyostosis bony bosses are present on the skull, similar to Burnetia and Proburnetia, but with a different appearance. The premaxilla is not preserved, but the remaining portion of the maxilla forms most of the side of the snout, exhibiting a rugose surface anteriorly and reaching the dorsal limit below the dorsomedially positioned nasal boss. The paired nasals do not have a large exposure on the skull roof, and the anterior portion is not preserved. The prefrontal is a large bone forming the anterodorsal and dorsal margins of the orbit, and above the orbit, it forms a prominent supraorbital boss, thinning anteriorly and extending to the lateral side of the skull as far as the nasal boss. The lacrimal has a large exposure anterior to the orbit, with a prominent rectangular fossa on its anterodorsal side bordering the prefrontal dorsally and the maxilla anteriorly. The zygomatic arch is thick and poorly defined, with unclear sutural contacts between the elements. The postorbital is narrow when viewed from the side, and its sutural borders are unclear.(BRUCE S. RUBIDGE and JAMES W. KITCHING)

Bullacephalus Temporal range: Late Permian
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Synapsida
Clade:	Therapsida
Suborder:	†Biarmosuchia
Family:	†Burnetiidae
Genus:	†Bullacephalus Rubidge and Kitching, 2003
Species:	†B. jacksoni
Binomial name
†Bullacephalus jacksoni Rubidge and Kitching, 2003

Bullacephalus is an extinct genus of biarmosuchian therapsids belonging to the family Burnetiidae. The type species B. jacksoni was named in 2003. It is known from a relatively complete skull and lower jaw, discovered in the Late Permian Tapinocephalus Assemblage Zone of the Beaufort Group of South Africa.^[1]

1. 1. 1. Day, M. O., Smith, R. M., Benoit, J., Fernandez, V., & Rubidge, B. S. (2018). A new species of burnetiid (Therapsida, Burnetiamorpha) from the early wuchiapingian of South Africa and implications for the evolutionary ecology of the family Burnetiidae. Papers in Palaeontology, 4(3), 453–475. https://doi.org/10.1002/spp2.1114
      2. Day, M., Rubidge, B., & Abdala, F. (2016). A new mid-permian burnetiamorph therapsid from the main Karoo Basin of South Africa and a phylogenetic review of Burnetiamorpha. Acta Palaeontologica Polonica, 61. https://doi.org/10.4202/app.00296.2016
      3. Kruger, A., Rubidge, B. S., Abdala, F., Chindebvu, E. G., & Jacobs, L. L. (2015). lende chiweta, a new therapsid from Malawi, and its influence on Burnetiamorph phylogeny and biogeography. Journal of Vertebrate Paleontology, 35(6). https://doi.org/10.1080/02724634.2015.1008698
      4. Sidor, C. A., & Welman, J. (2003). A second specimen oflemurosaurus pricei(therapsida: Burnetiamorpha). Journal of Vertebrate Paleontology, 23(3), 631–642. https://doi.org/10.1671/0272-4634(2003)023[0631:assolp]2.0.co;2
      5. Sidor, C. A., Hopson, J. A., & Keyser, A. W. (2004). A new burnetiamorph therapsid from the Teekloof Formation, Permian, of South Africa. Journal of Vertebrate Paleontology, 24(4), 938–950. https://doi.org/10.1671/0272-4634(2004)024[0938:anbtft]2.0.co;2
      6. Kammerer, C., & Sidor, C. (2020). A new burnetiid from the mid-permian of zambia and a reanalysis of Burnetiamorph Relationships (project). MorphoBank Datasets. https://doi.org/10.7934/p3785
      7. Rubidge, B. S., & Kitching, J. W. (2003). A new burnetiamorph (Therapsida: Biarmosuchia) from the Lower Beaufort Group of South Africa. Palaeontology, 46(1), 199–210. https://doi.org/10.1111/1475-4983.00294
      8. Liu, J., Rubidge, B., & Li, J. (2009). A new specimen of biseridens qilianicus indicates its phylogenetic position as the most basal anomodont. Proceedings of the Royal Society B: Biological Sciences, 277(1679), 285–292. https://doi.org/10.1098/rspb.2009.0883
      9. SIDOR, Christian. (2003). The Naris and palate of Lycaenodon longiceps (Therapsida: BIARMOSUCHIA), with comments on their early evolution in the Therapsida. Journal of Paleontology, 77(5), 977–984. https://doi.org/10.1666/0022-3360(2003)077<0977:tnapol>2.0.co;2
      10. Smith, R. M., Rubidge, B. S., & Sidor, C. A. (2006). A new burnetiid (Therapsida: Biarmosuchia) from the Upper Permian of South Africa and its biogeographic implications. Journal of Vertebrate Paleontology, 26(2), 331–343. https://doi.org/10.1671/0272-4634(2006)26[331:anbtbf]2.0.co;2

This therapsid-related article is a stub. You can help Wikipedia by expanding it.

• v
• t
• e