Earth:Abrahamskraal Formation

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Short description: Geological formation of the Beaufort Group in South Africa
Abrahamskraal Formation
Stratigraphic range: Wordian-Capitanian
~268–259 Ma
Hill at Karoo National Park.png
Hill with outcropping Teekloof and Abrahamskraal Formations
TypeGeological formation
Unit ofBeaufort Group
Sub-unitsTapinocephalus Assemblage Zone, Eodicynodon Assemblage Zone
UnderliesTeekloof Formation
OverliesEcca Group
Thicknessup to 2,565 m (8,415 ft)
Lithology
PrimaryMudstone, sandstone
OtherSiltstone
Location
Coordinates [ ⚑ ] : 31°24′S 23°06′E / 31.4°S 23.1°E / -31.4; 23.1
RegionNorthern, Western & Eastern Cape
Country South Africa
Type section
Named forAbrahams Kraal 29 (farm), 18 km south of Leeu-Gamka
Named byA.W. Keyser, P.J. Rossouw & Lieuwe Dirk Boonstra
Geology of Karoo Supergroup.png
A simplified geological map of the outcrops of Karoo Supergroup rocks in Southern Africa. The Beaufort Group is represented by the yellow key on the map.

The Abrahamskraal Formation is a geological formation and is found in numerous localities in the Northern Cape, Western Cape, and the Eastern Cape of South Africa . It is the lowermost formation of the Adelaide Subgroup of the Beaufort Group, a major geological group that forms part of the greater Karoo Supergroup. It represents the first fully terrestrial geological deposits of the Karoo Basin. Outcrops of the Abrahamskraal Formation are found from the small town Middelpos in its westernmost localities, then around Sutherland, the Moordenaarskaroo north of Laingsburg, Williston, Fraserburg, Leeu-Gamka, Loxton, and Victoria West in the Western Cape and Northern Cape. In the Eastern Cape outcrops are known from Rietbron, north of Klipplaat and Grahamstown, and also southwest of East London.[1][2]

Geology

The Abrahamskraal Formation comprises the majority of the Middle Permian Beaufort sequence, and are thought to range between 268 - 259 million years in age. The lowermost deposits of the Abrahamskraal Formation found in the Eastern Cape until recently were named the Koonap Formation, but these outcrops have been amalgamated into the Abrahamskraal Formation due to recent stratigraphic and biostratigraphic research.[3] The Abrahamskraal Formation incorporates the entire Tapinocephalus Assemblage Zone in its upper sections and the entire Eodicynodon Assemblage Zone its lowermost southern deposits. In the west and northerly deposits the Abrahamskraal Formation overlies the Waterford Formation and the Middleton Formation in the south, both formations containing the uppermost deposits of the Ecca Group.

The rocks of the Abrahamskraal Formation comprise mainly greenish-grey to blueish-grey mudstone coupled with rarer instances of greyish-red, reddish-brown or purple mudstones. These include subordinate greenish-grey, fine-grained sandstones which are normally observed in fining upward cycles. The sandstones vary in thickness from several metres to several tens of metres in some localities. Siltstones are also found interbedded with the mudstone beds. The presence of these rocks reveal much about the past environment that they were deposited in. They were formed by sedimentary material being deposited in the Karoo Basin - a retro-arc foreland basin - by vast, low-energy alluvial plains flowing northwards from the south. The lowermost deposits are considered to be deltaic and grade laterally into the underlying Ecca Group deposits in its southern localities. Deposits grade steadily younger in the northeast where the sedimentary facies turn fully terrestrial. The greenish-grey mudstones are usually associated with the deltaic sedimentary facies while the redder mudstones with the terrestrial.[4][5][6][7][8]

All sedimentary rocks of the Karoo Basin were transported downhill from the south in the shadow of the rising Gondwanide mountain range. The Gondwanides were the result of tectonic uplift that had previously begun to take course due to subduction of the Palaeo-pacific plate beneath the Gondwanan Plate. Orogenic pulses from the growing Gondwanides mountain chain and associated subduction created accommodation space for sedimentation in the Karoo Basin where the deposits of the Abrahamskraal Formation and all succeeding deposits of the Karoo Basin were deposited over millions of years.[9][10][11][12][13][14][15][16]

Paleontological significance

The Abrahamskraal Formation is highly fossiliferous and well known for its biozone assemblages of therapsid fossils.[17][18][19][20] The Eodicynodon and Tapinocephalus Assemblage Zones to which this geological formation incorporates preserve the first appearance of the earliest dicynodonts, dinocephalians, biarmosuchians, therocephalians, gorgonopsians,[21][22] and pareiasaurian parareptiles.[23][24][25][26][27][28][29][30][31][32][33][34] The upper sections of this formation document the rise of and diversification of the dinocephalians.[35][36][37][38][39] The dinocephalians subsequently went extinct at the contact of the Abrahamskraal Formation with the overlying Teekloof Formation.[40][41][42] The basal pelycosaur synapsid species, Elliotsmithia longiceps, has also been found in the deposits of this formation.[43][44][45] The presence of this basal synapsid is indicative of this geological formations significance. For decades, paleontologists have puzzled over what has been termed Olsen’s Gap, which is used to describe the evolutionary gap in the tetrapod fossil record between the appearance of the more derived therapsids and their ancestors, the pelycosaurs. The rocks of the Abrahamskraal Formation and its geological correlates abroad hold the promise of that fossil gap being bridged through future research endeavors in the years to come. More notable fossil species includes the dicynodont Diictodon feliceps which first appears in the upper sections of this formation, remaining ubiquitous until the Permian-Triassic boundary.[46][47][48] Finally, fossils of temnospondyl amphibians such as of Rhinesuchus, the fish Namaichthys, invertebrate fossils of molluscs, invertebrate trackways and burrows, vertebrate footprints of therapsids, and a variety of plant fossils such as Dadoxylon, Equisetum modderdriftensis, Schizoneura africana, and several different species of Glossopteris have been recovered.[49][50]

Among the species found in the Abrahamskraal Formation is Moschops Capensis [51]

Correlation

The Abrahamskraal Formation corresponds with numerous localities abroad. Currently it is considered to correlate chronostratigraphically with the Rio do Rasto Formation from the Paraná Basin in Brazil ,[52][53] the Madumabisa Mudstone Formation of Zambia,[54] the Ocher and Isheevo faunas of Russia ,[55] and to the Dashankou fauna from the Xidagou Formation of China . However, correlative dating between the Xidagou Formation and the Abrahamskraal Formation remains inconsistent and needs further study.

References

  1. ↑ Day, M. O.; Rubidge, B. S. (2014-12-01). "A brief lithostratigraphic review of the Abrahamskraal and Koonap formations of the Beaufort Group, South Africa: Towards a basin-wide stratigraphic scheme for the Middle Permian Karoo" (in en). Journal of African Earth Sciences 100: 227–242. doi:10.1016/j.jafrearsci.2014.07.001. ISSN 1464-343X. Bibcode: 2014JAfES.100..227D. 
  2. ↑ Merrill van der Walt; Michael Day; Bruce Rubidge; Antony K. Cooper; Inge Netterberg4 (2010) (in en). A new GIS-based biozone map of the Beaufort Group (Karoo Supergroup), South Africa. 45. pp. 1–6. https://www.researchgate.net/publication/239521002. Retrieved 2018-11-27. 
  3. ↑ Cole, D.I.; Johnson, M.R.; Day, M.O. (2016-06-01). "Lithostratigraphy of the Abrahamskraal Formation (Karoo Supergroup), South Africa". South African Journal of Geology 119 (2): 415–424. doi:10.2113/gssajg.119.2.415. ISSN 1012-0750. Bibcode: 2016SAJG..119..415C. 
  4. ↑ Smith, R. M. H.; Eriksson, P. G.; Botha, W. J. (1993-01-01). "A review of the stratigraphy and sedimentary environments of the Karoo-aged basins of Southern Africa" (in en). Journal of African Earth Sciences (and the Middle East) 16 (1–2): 143–169. doi:10.1016/0899-5362(93)90164-L. ISSN 0899-5362. Bibcode: 1993JAfES..16..143S. 
  5. ↑ Catuneanu, Octavian; Bowker, Duncan (2001-01-01). "Sequence stratigraphy of the Koonap and Middleton fluvial formations in the Karoo foredeep South Africa" (in en). Journal of African Earth Sciences 33 (3–4): 579–595. doi:10.1016/S0899-5362(01)00095-1. ISSN 1464-343X. Bibcode: 2001JAfES..33..579C. 
  6. ↑ Rubidge, B. S. (ed.) 1995b. Biostratigraphy of the Beaufort Group (Karoo Supergroup). South African Committee of Stratigraphy. Biostratigraphic Series 1. Pretoria, Council for Geoscience.
  7. ↑ Cole, D.I.; Johnson, M.R.; Day, M.O. (2016-06-01). "Lithostratigraphy of the Abrahamskraal Formation (Karoo Supergroup), South Africa" (in en). South African Journal of Geology 119 (2): 415–424. doi:10.2113/gssajg.119.2.415. ISSN 1012-0750. Bibcode: 2016SAJG..119..415C. 
  8. ↑ J., Hancox, P.; S., Rubidge, B. (1997). "The role of fossils in interpreting the development of the Karoo Basin" (in en). Palaeontologia Africana. ISSN 0078-8554. http://146.141.12.21/handle/10539/16396. 
  9. ↑ Kitching, J. W. (1970). A short review of the Beaufort zoning in South Africa. In Second Gondwana Symposium Proceedings and Papers (Vol. 1, pp. 309-312).
  10. ↑ Keyser, A.W. and Smith, R.M.H., 1978. Vertebrate biozonation of the Beaufort Group with special reference to the western Karoo Basin. Geological Survey, Department of Mineral And Energy Affairs, Republic of South Africa.
  11. ↑ J., Hancox, P.; S., Rubidge, B. (1997). "The role of fossils in interpreting the development of the Karoo Basin" (in en). Palaeontologia Africana. ISSN 0078-8554. http://146.141.12.21/handle/10539/16396. 
  12. ↑ Jirah, Sifelani; Rubidge, Bruce S. (2014-12-01). "Refined stratigraphy of the Middle Permian Abrahamskraal Formation (Beaufort Group) in the southern Karoo Basin". Journal of African Earth Sciences 100: 121–135. doi:10.1016/j.jafrearsci.2014.06.014. ISSN 1464-343X. Bibcode: 2014JAfES.100..121J. 
  13. ↑ Catuneanu, O.; Hancox, P.J.; Rubidge, B.S. (1998-12-01). "Reciprocal flexural behaviour and contrasting stratigraphies: a new basin development model for the Karoo retroarc foreland system, South Africa" (in en). Basin Research 10 (4): 417. doi:10.1046/j.1365-2117.1998.00078.x. ISSN 1365-2117. Bibcode: 1998BasR...10..417C. http://www.earthdoc.org/publication/publicationdetails/?publication=62697. 
  14. ↑ Catuneanua, O.; Hancox, P. J.; Cairncross, B.; Rubidge, B. S. (2002-11-01). "Foredeep submarine fans and forebulge deltas: orogenic off-loading in the underfilled Karoo Basin" (in en). Journal of African Earth Sciences 35 (4): 489–502. doi:10.1016/S0899-5362(02)00154-9. ISSN 1464-343X. Bibcode: 2002JAfES..35..489C. 
  15. ↑ Catuneanu, Octavian (2004). "Basement control on flexural profiles and the distribution of foreland facies: The Dwyka Group of the Karoo Basin, South Africa" (in en). Geology 32 (6): 517. doi:10.1130/G20526.1. ISSN 0091-7613. Bibcode: 2004Geo....32..517C. 
  16. ↑ Clevis, Quintijn; De Boer, Poppe L.; Nijman, Wouter (2004-06-30). "Differentiating the effect of episodic tectonism and eustatic sea-level fluctuations in foreland basins filled by alluvial fans and axial deltaic systems: insights from a three-dimensional stratigraphic forward model" (in en). Sedimentology 51 (4): 809–835. doi:10.1111/j.1365-3091.2004.00652.x. ISSN 0037-0746. Bibcode: 2004Sedim..51..809C. 
  17. ↑ Seeley, H.G. (1892). "Researches on the structure, organization, and classification of the fossil Reptilia. VII. Further observations on Pareiasaurus". Philosophical Transactions of the Royal Society of London B 183: 311–370. doi:10.1098/rstb.1892.0008. 
  18. ↑ Broom, R (1906). "V.—On the Permian and Triassic Faunas of South Africa". Geological Magazine 3 (1): 29–30. doi:10.1017/s001675680012271x. Bibcode: 1906GeoM....3...29B. https://zenodo.org/record/1687495. 
  19. ↑ Watson, D.M.S. (1914). "II.—The Zones of the Beaufort Beds of the Karroo System in South Africa". Geological Magazine 1 (5): 203–208. doi:10.1017/s001675680019675x. Bibcode: 1914GeoM....1..203W. https://zenodo.org/record/1506035. 
  20. ↑ Cisneros, Juan Carlos; Abdala, Fernando; Jashashvili, Tea; Bueno, Ana de Oliveira; Dentzien-Dias, Paula (2015-07-01). "Tiarajudens eccentricus and Anomocephalus africanus, two bizarre anomodonts (Synapsida, Therapsida) with dental occlusion from the Permian of Gondwana" (in en). Royal Society Open Science 2 (7): 150090. doi:10.1098/rsos.150090. ISSN 2054-5703. PMID 26587266. Bibcode: 2015RSOS....250090C. 
  21. ↑ Kammerer, Christian F. (2013-09-21), "A Redescription of Eriphostoma microdon Broom, 1911 (Therapsida, Gorgonopsia) from the Tapinocephalus Assemblage Zone of South Africa and a Review of Middle Permian Gorgonopsians" (in en), Early Evolutionary History of the Synapsida, Vertebrate Paleobiology and Paleoanthropology, Springer Netherlands, pp. 171–184, doi:10.1007/978-94-007-6841-3_11, ISBN 9789400768406 
  22. ↑ Kammerer, Christian F.; Smith, Roger M. H.; Day, Michael O.; Rubidge, Bruce S. (2015-02-16). "New information on the morphology and stratigraphic range of the mid-Permian gorgonopsianEriphostoma microdonBroom, 1911" (in en). Papers in Palaeontology 1 (2): 201–221. doi:10.1002/spp2.1012. ISSN 2056-2802. 
  23. ↑ Bain, A.G. (1845). "On the discovery of the fossil remains of bidental and other reptiles in South Africa". Quarterly Journal of the Geological Society 1 (1): 317–318. doi:10.1144/gsl.jgs.1845.001.01.72. https://zenodo.org/record/1673362. 
  24. ↑ Cluver, M.A., 1975. A New Didynodont Reptile from the Tapinocephalus Zone [Karoo System, Beaufort Series] of South Africa, with Evidence of the Jaw Adductor Musculature.
  25. ↑ A., Cluver, Michael (1983). "reassessment of the relationships of Permian Dicynodontia (Reptilia, Therapsida) and a new classifications of dicynodonts" (in en). AGRIS: International Information System for the Agricultural Science and Technology. ISBN 9780868130439. http://agris.fao.org/agris-search/search.do?recordID=US201300360256. 
  26. ↑ Boonstra, L. D. (1934). "A contribution to the morphology of the mammal-like reptiles of the sub-order Therocephalia". Annals of the South African Museum 31: 215–267. 
  27. ↑ Broom, R (1935). "On some new genera and species of Karroo fossil reptiles". Annals of the Transvaal Museum 18: 55–72. 
  28. ↑ Boonstra, L. D. 1948. Anomodont reptiles from the Tapinocephalus zone of the Karroo System. In: Du Toit, A. L. (ed.) Special Publications of the Royal Society of South Africa. Robert Broom Commemorative Volume., 57-64. Cape Town: The Royal Society.
  29. ↑ Broom, R (1948). "A contribution to our knowledge of the vertebrates of the Karroo Beds of South Africa". Transactions of the Royal Society of Edinburgh 61 (2): 577–629. doi:10.1017/s0080456800004865. 
  30. ↑ Cluver, M. A. (1975). "A new dicynodont reptile from the Tapinocephalus Zone (Karoo System, Beaufort series) of South Africa, with evidence of the jaw adductor musculature". Annals of the South African Museum 67: 7–23. 
  31. ↑ Rubidge, B.S.; King, G.M.; Hancox, P.J. (in en). The postcranial skeleton of the earliest dicynodont synapsid Eodicynodon from the Upper Permian of South Africa. 37. pp. 397–408. https://www.researchgate.net/publication/239523242. Retrieved 2018-11-27. 
  32. ↑ Cisneros, Juan Carlos; Rubidge, Bruce S.; Mason, Richard; Dube, Charlton (2008-01-01). "Analysis of millerettid parareptile relationships in the light of new material ofBroomia perplexaWatson, 1914, from the Permian of South Africa" (in en). Journal of Systematic Palaeontology 6 (4): 453–462. doi:10.1017/s147720190800254x. ISSN 1477-2019. 
  33. ↑ Angielczyk, Kenneth D.; Rubidge, Bruce S.; Day, Michael O.; Lin, Florence (2016-02-06). "A reevaluation ofBrachyprosopus broomiandChelydontops altidentalis, dicynodonts (Therapsida, Anomodontia) from the middle PermianTapinocephalusAssemblage Zone of the Karoo Basin, South Africa" (in en). Journal of Vertebrate Paleontology 36 (2): e1078342. doi:10.1080/02724634.2016.1078342. ISSN 0272-4634. Bibcode: 2016JVPal..36E8342A. 
  34. ↑ Lyson, Tyler R.; Bever, Gabe S.; Scheyer, Torsten M.; Hsiang, Allison Y.; Gauthier, Jacques A. (2013-06-17). "Evolutionary Origin of the Turtle Shell" (in en). Current Biology 23 (12): 1113–1119. doi:10.1016/j.cub.2013.05.003. ISSN 0960-9822. PMID 23727095. 
  35. ↑ "A NEW GENUS OF PRIMITIVE DINOCEPHALIAN─THE THIRD REPORT ON LATE PERMIAN DASHANKOU LOWER TETRAPOD FAUNA--《VERTEBRATA PALASIATICA》1997年01期". http://en.cnki.com.cn/Article_en/CJFDTOTAL-GJZD199701005.htm. 
  36. ↑ ANGIELCZYK, KENNETH D.; RUBIDGE, BRUCE S. (2010-09-01). "A new pylaecephalid dicynodont (Therapsida, Anomodontia) from theTapinocephalusAssemblage Zone, Karoo Basin, Middle Permian of South Africa" (in en). Journal of Vertebrate Paleontology 30 (5): 1396–1409. doi:10.1080/02724634.2010.501447. ISSN 0272-4634. Bibcode: 2010JVPal..30.1396A. 
  37. ↑ Boos, A. D. S.; Kammerer, C. F.; Schultz, C. L.; Paes Neto, V. D. (2015-11-01). "A tapinocephalid dinocephalian (Synapsida, Therapsida) from the Rio do Rasto Formation (Paraná Basin, Brazil): Taxonomic, ontogenetic and biostratigraphic considerations" (in en). Journal of South American Earth Sciences 63: 375–384. doi:10.1016/j.jsames.2015.09.003. ISSN 0895-9811. Bibcode: 2015JSAES..63..375B. 
  38. ↑ Boonstra, L.D., 1969. The fauna of the Tapinocephalus Zone (Beaufort beds of the Karoo)
  39. ↑ Atayman, S., Rubidge, B.S. and Abdala, F., 2009. Taxonomic re-evaluation of tapinocephalid dinocephalians. Palaeontologia africana, 44, p.88Á90. Link: https://core.ac.uk/download/pdf/39675877.pdf#page=88
  40. ↑ Lucas, S.G., 2001. A global hiatus in the Middle Permian tetrapod fossil record. Permophiles, 38, pp.24-27. Link: http://www.nigpas.ac.cn/qt/tethys_en/edit/UploadFile/200568142141602.pdf#page=26
  41. ↑ Day, Michael O.; Ramezani, Jahandar; Bowring, Samuel A.; Sadler, Peter M.; Erwin, Douglas H.; Abdala, Fernando; Rubidge, Bruce S. (2015-07-22). "When and how did the terrestrial mid-Permian mass extinction occur? Evidence from the tetrapod record of the Karoo Basin, South Africa" (in en). Proc. R. Soc. B 282 (1811): 20150834. doi:10.1098/rspb.2015.0834. ISSN 0962-8452. PMID 26156768. 
  42. ↑ Bond, D.P.G.; Wignall, P.B.; Wang, W.; Izon, G.; Jiang, H.-S.; Lai, X.-L.; Sun, Y.-D.; Newton, R.J. et al. (2010-06-01). "The mid-Capitanian (Middle Permian) mass extinction and carbon isotope record of South China" (in en). Palaeogeography, Palaeoclimatology, Palaeoecology 292 (1–2): 282–294. doi:10.1016/j.palaeo.2010.03.056. ISSN 0031-0182. Bibcode: 2010PPP...292..282B. 
  43. ↑ Reisz, Robert R.; Dilkes, David W.; Berman, David S. (1998-09-15). "Anatomy and relationships ofElliotsmithia longicepsBroom, a small synapsid (Eupelycosauria: Varanopseidae) from the late Permian of South Africa" (in en). Journal of Vertebrate Paleontology 18 (3): 602–611. doi:10.1080/02724634.1998.10011087. ISSN 0272-4634. Bibcode: 1998JVPal..18..602R. 
  44. ↑ MODESTO, SEAN; SIDOR, CHRISTIAN A.; RUBIDGE, BRUCE S.; WELMAN, JOHANN (2007-01-02). "A second varanopseid skull from the Upper Permian of South Africa: implications for Late Permian 'pelycosaur' evolution" (in en). Lethaia 34 (4): 249–259. doi:10.1111/j.1502-3931.2001.tb00053.x. ISSN 0024-1164. 
  45. ↑ Botha-Brink, Jennifer; Modesto, Sean P. (2007-11-22). "A mixed-age classed 'pelycosaur' aggregation from South Africa: earliest evidence of parental care in amniotes?" (in en). Proceedings of the Royal Society of London B: Biological Sciences 274 (1627): 2829–2834. doi:10.1098/rspb.2007.0803. ISSN 0962-8452. PMID 17848370. 
  46. ↑ Cluver, M.A. and Hotton, N., 1981. The genera Dicynodon and Diictodon and their bearing on the classification of the Dicynodontia (Reptilia, Therapsida). South African Museum.
  47. ↑ Ray, Sanghamitra; Chinsamy, Anusuya (2004-03-25). "Diictodon feliceps(Therapsida, Dicynodontia): bone histology, growth, and biomechanics" (in en). Journal of Vertebrate Paleontology 24 (1): 180–194. doi:10.1671/1914-14. ISSN 0272-4634. Bibcode: 2004JVPal..24..180R. 
  48. ↑ Angielczyk, Kenneth D.; Sullivan, Corwin (2008-09-12). "Diictodon feliceps(Owen, 1876), a dicynodont (Therapsida, Anomodontia) species with a Pangaean distribution" (in en). Journal of Vertebrate Paleontology 28 (3): 788–802. doi:10.1671/0272-4634(2008)28[788:dfoadt2.0.co;2]. ISSN 0272-4634. 
  49. ↑ Benton, M. J. (2012-03-02). "No gap in the Middle Permian record of terrestrial vertebrates" (in en). Geology 40 (4): 339–342. doi:10.1130/G32669.1. ISSN 0091-7613. Bibcode: 2012Geo....40..339B. 
  50. ↑ Damiani, R. J. (2004-01-01). "Temnospondyls from the Beaufort Group (Karoo Basin) of South Africa and Their Biostratigraphy" (in en). Gondwana Research 7 (1): 165–173. doi:10.1016/S1342-937X(05)70315-4. ISSN 1342-937X. Bibcode: 2004GondR...7..165D. 
  51. ↑ "Biostratigraphy of the Tapinocephalus Assemblage Zone (Beaufort Group, Karoo Supergroup), South Africa". Geoscienceworld. https://pubs.geoscienceworld.org/gssa/sajg/article-abstract/123/2/149/587463/Biostratigraphy-of-the-Tapinocephalus-Assemblage. 
  52. ↑ Cisneros, Juan Carlos; Abdala, Fernando; Rubidge, Bruce S.; Dentzien-Dias, Paula Camboim; Bueno, Ana de Oliveira (2011-03-25). "Dental Occlusion in a 260-Million-Year-Old Therapsid with Saber Canines from the Permian of Brazil" (in en). Science 331 (6024): 1603–1605. doi:10.1126/science.1200305. ISSN 0036-8075. PMID 21436452. Bibcode: 2011Sci...331.1603C. 
  53. ↑ Cisneros, Juan Carlos; Abdala, Fernando; Atayman-Güven, Saniye; Rubidge, Bruce S.; Şengör, A. M. Celâl; Schultz, Cesar L. (2012-01-31). "Carnivorous dinocephalian from the Middle Permian of Brazil and tetrapod dispersal in Pangaea" (in en). Proceedings of the National Academy of Sciences 109 (5): 1584–1588. doi:10.1073/pnas.1115975109. ISSN 0027-8424. PMID 22307615. Bibcode: 2012PNAS..109.1584C. 
  54. ↑ Sidor, Christian A.; Angielczyk, Kenneth D.; Smith, Roger M. H.; Goulding, Adam K.; Nesbitt, Sterling J.; Peecook, Brandon R.; Steyer, J. Sébastien; Tolan, Stephen (2014-06-07). "Tapinocephalids (Therapsida, Dinocephalia) from the Permian Madumabisa Mudstone Formation (Lower Karoo, Mid-Zambezi Basin) of southern Zambia" (in en). Journal of Vertebrate Paleontology 34 (4): 980–986. doi:10.1080/02724634.2013.826669. ISSN 0272-4634. Bibcode: 2014JVPal..34..980S. 
  55. ↑ Lucas, Spencer G.; Zeigler, Kate E. (2005) (in en). The Nonmarine Permian: Bulletin 30. New Mexico Museum of Natural History and Science. https://books.google.com/books?id=7r75CQAAQBAJ&q=Lucas,+S.+G.+2005a.+Dicynodon+(Reptilia:Therapsida)+from+the+Upper+Permian+of+Russia:+Biochronologic+significance.+New+Mexico+Museum+of+Natural+History+and+Science+Bulletin,+30,+192%E2%80%93196.&pg=PA192. 



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