Abrahamskraal Formation Explained

Abrahamskraal Formation
Type:	Geological formation
Age:	Wordian-Capitanian ~
Period:	Capitanian
Prilithology:	Mudstone, sandstone
Otherlithology:	Siltstone
Namedfor:	Abrahams Kraal 29 (farm), 18 km south of Leeu-Gamka
Namedby:	A.W. Keyser, P.J. Rossouw & Lieuwe Dirk Boonstra
Region:	Northern, Western & Eastern Cape
Coordinates:	-31.4°N 29°W
Unitof:	Beaufort Group
Underlies:	Teekloof Formation
Overlies:	Ecca Group
Thickness:	up to 2565m (8,415feet)
Map:	Geology of Karoo Supergroup.png
Paleocoordinates:	-59.9°N -38.9°W

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]}

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.^{[8] [9] [10] [11] [12] [13] [14]}

Paleontological significance

The Abrahamskraal Formation is highly fossiliferous and well known for its biozone assemblages of therapsid fossils.^{[15] [16] [17] [18]} The Eodicynodon and Tapinocephalus Assemblage Zones to which this geological formation incorporates preserve the first appearance of the earliest dicynodonts, dinocephalians, biarmosuchians, therocephalians, gorgonopsians,^[19] and pareiasaurian parareptiles.^{[20] [21] [22] [23] [24] [25] [26] [27] [28] [29] [30] [31]} The upper sections of this formation document the rise of and diversification of the dinocephalians.^{[32] [33] [34] [35] [36]} The dinocephalians subsequently went extinct at the contact of the Abrahamskraal Formation with the overlying Teekloof Formation.^{[37] [38] [39]} The basal pelycosaur synapsid species, Elliotsmithia longiceps, has also been found in the deposits of this formation.^{[40] [41] [42]} 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 include the dicynodont Diictodon feliceps which first appears in the upper sections of this formation, remaining ubiquitous until the Permian-Triassic boundary.^{[43] [44] [45]} 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.^{[46] [47]}

Among the species found in the Abrahamskraal Formation is Moschops Capensis ^[48]

Paleobiota

Amphibians

Amphibians of the Abrahamskraal Formation
Taxa	Species	Locality	Assemblage Zone	Material	Notes	Images
Rhinesuchus^[49]	R. tenuceps	Farm Stinkfontein, Prince Albert District	Tapinocephalus A-Z.	A skull associated with a partial left mandibular ramus.	A temnospondyl amphibian.
	R. whaitsi	Leeu-Gamka, Prince Albert District		A basicranium, seven fragments of the middle portion of the left hemi-mandible, and multiple skull fragments.

Fish

Actinopterygian

Actinopterygians of the Abrahamskraal Formation
Taxa	Species	Locality	Assemblage Zone	Material	Notes	Images
Bethesdaichthys	B. kitchingi	Blourug farm, Victoria West.	Tapinocephalus A-Z	A preserved skull.	An actinopterygian fish.
Blourugia^[50]	B. seeleyi	Blourug farm, Victoria West.	Tapinocephalus A-Z	A partial skeleton.	An actinopterygian fish.
Westlepis	W. kempeni	Blourug farm, Victoria West	Tapinocephalus A-Z		An actinopterygian fish.

Reptiles

Sauropsida

Sauropsids of the Abrahamskraal Formation
Taxa	Species	Locality	Assemblage Zone	Material	Notes	Images
Australothyris	A. smithi	Beukesplaas farm	Upper part of Tapinocephalus A-Z	A skull and portions of the rest of the skeleton	A parareptile.
Bradysaurus	B. baini	Prince Albert, Leeu Gamka, Hottentotsrivier Farm, Leeurivier, Mynhardtskraal, Groot Kruidfortein, Zwarts Siding, Sutherland, and Knoffelfortein.	Tapinocephalus A-Z	A complete skull and separate lower jaw with a complete postcranial skeleton consisting of a complete shoulder girdle and pelvis, a complete vertebral column with few missing at the end of the caudal vertebrae. The right fore and hind limbs are complete. The left humerus, radius, ulna, femur, tibia, and fibula are partially preserved.	A pareiasaur.
	B. seeleyi			A partial skeleton consists of a complete skull, lower jaw, partial vertebral column, some ribs, osteoderms, and parts of girdles.
Embrithosaurus	E. schwarzi	Hoogeveld farm.	Tapinocephalus A-Z	Distorted skull with the occluded lower jaw, vertebrae 1 to 27 with articulated osteoderms, two small articulated caudal vertebrae, partial left scapulocoracoid, cleithrum, left and right clavicle, and interclavicle, complete right humerus, partial left humerus, complete right radius, partial left radius, both ulnae complete, both femora complete, both tibia complete, right fibula, partial left fibula, complete pelvis, two digits of the forelimb and two digits of the hindlimb	A pareiasaur.
Eunotosaurus	E. africanus	De bad farm, Prince Albert, Boesmanrivier and Rietfortien	Upper Tapinocephalus A-Z and parts of Pristerognathus A-Z.	Fossilized ribbones.	An early relative of reptile.

Synapsids

Therapsids

= Chainosauria

=

Chainosaurs of the Abrahamskraal Formation
Taxa	Species	Locality	Assemblage Zone	Material	Notes	Images
Galechirus	G. scholtzl	Victoria West	Tapinocephalus A-Z.	A partial skeleton	An insectivorous anomodont.
Patranomodon	P. nyaphulii	Prince Albert	Eodicynodon A-Z	A fossilized skull	A rare genus of anomodont.

= Dicynodontia

=

Dicynodonts of the Abrahamskraal Formation
Taxa	Species	Locality	Assemblage Zone	Material	Notes	Images
Brachyprosopus	B. broomi	Beukesplaas	Tapinocephalus A-Z	A skull.	A dicynodont.
Colobodectes ^[51]	C. cluveri	Keerom farm, Kruidfontein farm, Bastardsfontein farm, and Altringham farm.	Eodicynodon and Tapinocephalus A-Z	A skull lacking zygomatic arches and postorbital bars	A dicynodont.
Diictodon	D. feliceps	Prince Albert.	Tapinocephalus A-Z	Several skeletal specimens.	A pylaecephalid dicynodont.
Emydops	E. arctatus	Beaufort West and Prince Albert.	Either Tapinocephalus A-Z or Pristerognathus A-Z.	A partial skull	A dicynodont.
Eodicynodon	E. oosthuizeni	Tuinkraal and Zwartskraal farm, Prince Albert district	Tapinocephalus A-Z	Postcranial skeleton.	A dicynodont.
Eosimops	E. newtoni	Victoria West.	Tapinocephalus A-Z.	several skull specimens and one complete skeleton.	A pylaecephalid dicynodont.
	Nyaphulia^[52]	N. oelofseni	Botterkraal farm	Eodicynodon A-Z.	Partial skull, jaws, and teeth.	A dicynodont, formally named E. oelofseni.
Robertia	R. broomiana	Klein Koedoeskop, Beaufort West.	Lower part of the Tapinocephalus A-Z.	Partial skull and postcranial skeleton.	A small herbivorous dicynodont.

Biarmosuchia

Biarmosuchians of the Abrahamskraal Formation
Taxa	Species	Locality	Assemblage Zone	Material	Notes	Images
Hipposaurus	H. boonstrai	Beaufort west and Riet Fontein	Tapinocephalus A-Z	A single skull.	A hipposaurid therapsid.
	H. brinki			A preserved skull.
Nierkoppia	N. brucei	Farm Stellenboschvlei	Tapinocephalus A-Z.	A relatively well-preserved fragment of skull roof, preserving the interorbital and inter-temporal regions and dorso-medial portion of the occiput.	A proburnetiine burnetiamorph.

= Anteosauridae

=

Anteosaurs of the Abrahamskraal Formation
Taxa	Species	Locality	Assemblage Zone	Material	Notes	Images
Anteosaurus	A. magnificus	Beaufort West, Prince Albert, and Laingsburg	Tapinocephalus A-Z.	Several complete skulls, dentition, and partial postcranial skeleton.	A large carnivorous dinocephalian.
Australosyodon	A. nyaphuli	Prince Albert and Tuinkraal	Eodicynodon A-Z.	A skull and mandible with a preserved left side.	A dinocephalian.

= Tapinocephalidae

=

Tapinocephalians of the Abrahamskraal Formation
Taxa	Species	Locality	Assemblage Zone	Material	Notes	Images
Criocephalosaurus	C. vanderbyli	Prince Albert	Lower and Middle Tapinocephalus A-Z.	A skull cap consists of the frontals, parietals, postfrontals, and one pre-frontal.	A tapinocephalian therapsid.
Keratocephalus	K. moloch	Prince Albert, Leeu Gamka, and Buffelsvlei.	Tapinocephalus A-Z.	Variable skulls and postcrania.	A tapinocephalian therapsid.
Mormosaurus	M. seeleyi	Gouph tract	Tapinocephalus A-Z.	A partial skull.	A Tapinocephalian.
Moschops	M. capensis	De Cypher Farm and Hottentotsrivier.	Tapinocephalus A-Z.	Several skeletal specimens consist of skulls and postcranial skeletons.	A subaquatic tapinocephalian.
	M. koupensis
	M. romeri
Phocosaurus	P. megischion	Boesmansrivier and Vers Fontein/Jan Willem Fontein.	Tapinocephalus A-Z.	A partial skull.	A Tapinocephalian.
Tapinocaninus	T. pamelae	Modderdrift farm	Eodicynodon A-Z.	Paratypes consist of several skulls with few post-cranial skeletons.	A Tapinocephalian.
Tapinocephalus	T. atherstonei	Boesmanshoek and Prince Albert	Lower, Middle, and Upper part of the Tapinocephalus A-Z.	A skull and postcranial elements.	A giant herbivorous Tapinocephalian.
Struthiocephalus	S. whaitsi	Prince Albert	Lower to Middle Tapinocephalus A-Z.	A partial skull.	A Tapinocephalian.

= Styracocephalidae

=

= Titanosuchidae

=

Titanosuchids of the Abrahamskraal Formation
Taxa	Species	Locality	Assemblage Zone	Material	Notes	Images
Jonkeria	J. boonstai	Farm Uitkyk, Leeu-Gamka, Groot kruidfontein, Prince Albert, and Vers Fontein.	Tapinocephalus A-Z.	A skull and humerus.	An omnivorous titanosuchid dinocephalian.
	J. ingens			A complete skull.
	J. haughtoni			A crushed skull.
	J. koupensis			A complete pelvis bone.
	J. parva			A femur, radius, small humerus, and tarsal.
	J. rossouwi			The holotype consists of postcranial skeletons.
	J. truculenta			A skull and partial skeleton.
	J. vanderbyli			A complete skull.
Titanosuchus^[53]	T. ferox	Beaufort West, Prince Albert, Mynhardskraal, Veldmansrivier, and Lammerskraal.	Tapinocephalus A-Z	Fragmentary jaws and post-crania that include two left humeri, femur, and two phalanges.	A carnivorous titanosuchid dinocephalian.

Gorgonopsia

Gorgonopsians of the Abrahamskraal Formation
Taxa	Species	Locality	Assemblage Zone	Material	Notes	Images
Aelurosaurus	A. felinus	Beaufort west.	Tapinocephalus A-Z.	A holotype preserved skull.	A gorgonopsian.
	A. whaitsi			A holotype preserved skull.
Cerdodon	C. tenuidens	Beaufort west.	Tapinocephalus A-Z.	A holotype consists of a crushed skull.	A gorgonopsid.
Eriphostoma	E. microdon	Prince Albert, Hottentotsrivier farm, and Mynhardtskraal.	Tapinocephalus A-Z.	Partial skull remains.	A gorgonopsid formally named Galesuchus gracilis.
Phorcys	P. dubei	Delportsrivier	Eodicynodon and Tapinocephalus A-Z.	A partial skull from the occiput (the back face of the skull) up to the orbits, including the basicranium (the floor of the skull beneath the braincase), an eroded upper surface preserving the intact pre parietal and portions of the surrounding frontals and parietal bones, with a broken left zygomatic arch and a left palatine displaced into the left orbit,	A gorgonopsid.

Therocephalia

Therocephalians of the Abrahamskraal Formation
Taxa	Species	Locality	Assemblage Zone	Material	Notes	Images
Alopecodon	A. priscus	Zeekoegat, Prince Albert.	Tapinocephalus A-Z	A crushed partial skull and lower jaws.	A therocephalian.
Alopecognathus	A. megalops	Beaufort West and Prince Albert.	Tapinocephalus A-Z.	Skull specimens.	A therocephalian.
Eutheriodon	E. vandenheeveri	Modderdrift, Prince Albert.	Eodicynodon A-Z.	A partial snout and lower jaws.	A scylacosaurid therocephalian.
Glanosuchus	G. macrops	Gioflok’s Fontein, near Van der Byl’s Iird in the Gouph	Eodicynodon A-Z.	A holotype consists of a partial skull.	A scylacosaurid therocephalian.
Hyaenasuchus	H. whaitsi	Rietfontein	Tapinocephalus A-Z.	A weathered skull.	A therocephalian.
Ictidosaurus	I. angusticeps	Beaufort West	Eodicynodon and Tapinocephalus A-Z.	A holotype preserved skull.	A scylacosaurid therocephalian.
Pardosuchus	P. whaitsi	Prince Albert	Tapinocephalus A-Z.	Holotypes consist of preserved skulls.	A pristerognathinae therocephalian formally named Lycedops scholtzi.
Pristerognathus	P. minor	Beaufort West and Prince Albert.	Pristerognathus A-Z.	Multiple skull specimens.	A therocephalian.
	P. parvus
	P. vanderbyli
	P. vanwyki
Scymnosaurus	S. ferox	Prince Albert and Vers Fontein/Jan Willem Fortein	Tapinocephalus A-Z.	Partial skull consists of snout tip, dentition, and palate.	A therocephalian therapsids.
Tamboeria	T. maraisi	Prince Albert and Tamboers Fontein.	Tapinocephalus A-Z.		A middle-sized carnivorous therocephalian
Trochosuchus	T. acutus	Rietfontein and Prince Albert.	Tapinocephalus A-Z.	A fossilized skull.	A Lycosuchid therocephalian.
	T. intermedius
	T. major

Varanopidae

Varanopids of the Abrahamskraal Formation
Taxa	Species	Locality	Assemblage Zone	Material	Notes	Images
Anningia ^[54]	A. megalops	Prince Albert	The Middle of the Tapinocephalus A-Z.	A partial skull.	A varanopid synapsid.
Elliotsmithia	E. longiceps	Prince Albert	Tapinocephalus A-Z.	A holotype consists of a skull.	A small varanopid synapsid.
Heleosaurus	H. scholtzi	Victoria West.	Tapinocephalus A-Z.	A preserved skeleton.	A varanopid synapsid.
Microvaranops	M. parentis	Beukesplaas farm	Tapinocephalus A-Z.	A skeletal aggregation containing one grown and four immature individuals.	A varanopid synapsid.

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,^{[55] [56]} the Madumabisa Mudstone Formation of Zambia,^[57] the Ocher and Isheevo faunas of Russia,^[58] 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.

Notes and 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. Journal of African Earth Sciences. en. 100. 227–242. 10.1016/j.jafrearsci.2014.07.001. 2014JAfES.100..227D . 1464-343X.
2. Merrill van der Walt . Michael Day . Bruce Rubidge . Antony K. Cooper . Inge Netterberg. A new GIS-based biozone map of the Beaufort Group (Karoo Supergroup), South Africa. Palaeontologia Africana . 45 . 1–6 . 2010 . en. 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. 10.2113/gssajg.119.2.415. 2016SAJG..119..415C . 1012-0750.
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. Journal of African Earth Sciences (and the Middle East). en. 16. 1–2. 143–169. 10.1016/0899-5362(93)90164-L. 1993JAfES..16..143S . 0899-5362.
5. 2001-01-01. Sequence stratigraphy of the Koonap and Middleton fluvial formations in the Karoo foredeep South Africa. Journal of African Earth Sciences. en. 33. 3–4. 579–595. 10.1016/S0899-5362(01)00095-1. 1464-343X. Catuneanu. Octavian. Bowker. Duncan. 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. South African Journal of Geology. en. 119. 2. 415–424. 10.2113/gssajg.119.2.415. 2016SAJG..119..415C . 1012-0750.
8. 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).
9. 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.
10. 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. 10.1016/j.jafrearsci.2014.06.014. 2014JAfES.100..121J. 1464-343X.
11. 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. Basin Research. en. 10. 4. 417. 10.1046/j.1365-2117.1998.00078.x. 1998BasR...10..417C. 56420970 . 1365-2117.
12. 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. Journal of African Earth Sciences. en. 35. 4. 489–502. 10.1016/S0899-5362(02)00154-9. 2002JAfES..35..489C . 1464-343X.
13. Catuneanu. Octavian. 2004. Basement control on flexural profiles and the distribution of foreland facies: The Dwyka Group of the Karoo Basin, South Africa. Geology. en. 32. 6. 517. 10.1130/G20526.1. 2004Geo....32..517C. 0091-7613.
14. 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. Sedimentology. en. 51. 4. 809–835. 10.1111/j.1365-3091.2004.00652.x. 2004Sedim..51..809C. 128782169 . 0037-0746. free.
15. 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 . 10.1098/rstb.1892.0008 . free .
16. Broom . R . 1906 . V.—On the Permian and Triassic Faunas of South Africa . Geological Magazine . 3 . 1. 29–30 . 10.1017/s001675680012271x . 1906GeoM....3...29B . 129265956 .
17. 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 . 10.1017/s001675680019675x . 1914GeoM....1..203W . 130747924 .
18. 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. Royal Society Open Science. en. 2. 7. 150090. 10.1098/rsos.150090. 26587266. 2054-5703. 4632579. 2015RSOS....250090C.
19. 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. Papers in Palaeontology. en. 1. 2. 201–221. 10.1002/spp2.1012. 2015PPal....1..201K . 128762256 . 2056-2802.
20. 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 . 10.1144/gsl.jgs.1845.001.01.72 . 128602890 .
21. 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.
22. Cluver. Michael A.. 1983. reassessment of the relationships of Permian Dicynodontia (Reptilia, Therapsida) and a new classification of dicynodonts. AGRIS: International Information System for the Agricultural Science and Technology. 9780868130439. en.
23. 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 .
24. Broom . R . 1935 . On some new genera and species of Karroo fossil reptiles . Annals of the Transvaal Museum . 18 . 55–72 .
25. 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.
26. 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 . 10.1017/s0080456800004865 . 131663553 .
27. 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 .
28. The postcranial skeleton of the earliest dicynodont synapsid Eodicynodon from the Upper Permian of South Africa . Rubidge, B.S. . King, G.M. . Hancox, P.J. . Palaeontology . 37 . 2 . 397–408. en. 2018-11-27.
29. 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. Journal of Systematic Palaeontology. en. 6. 4. 453–462. 10.1017/s147720190800254x. 2008JSPal...6..453C . 73723455. 1477-2019.
30. 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. Journal of Vertebrate Paleontology. en. 36. 2. e1078342. 10.1080/02724634.2016.1078342. 2016JVPal..36E8342A . 130520407. 0272-4634.
31. 2013-06-17. Evolutionary Origin of the Turtle Shell. Current Biology. en. 23. 12. 1113–1119. 10.1016/j.cub.2013.05.003. 23727095. 0960-9822. Lyson. Tyler R.. Bever. Gabe S.. Scheyer. Torsten M.. Hsiang. Allison Y.. Gauthier. Jacques A.. free. 2013CBio...23.1113L .
32. Web site: A NEW GENUS OF PRIMITIVE DINOCEPHALIAN─THE THIRD REPORT ON LATE PERMIAN DASHANKOU LOWER TETRAPOD FAUNA--《VERTEBRATA PALASIATICA》1997年01期. en.cnki.com.cn. 2018-11-27.
33. 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. Journal of Vertebrate Paleontology. en. 30. 5. 1396–1409. 10.1080/02724634.2010.501447. 2010JVPal..30.1396A . 129846697. 0272-4634.
34. 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. Journal of South American Earth Sciences. en. 63. 375–384. 10.1016/j.jsames.2015.09.003. 2015JSAES..63..375B . 0895-9811.
35. Boonstra, L.D., 1969. The fauna of the Tapinocephalus Zone (Beaufort beds of the Karoo)
36. 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
37. 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
38. 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. Proc. R. Soc. B. en. 282. 1811. 20150834. 10.1098/rspb.2015.0834. 0962-8452. 26156768. 4528552.
39. Bond, D.P.G. . Wignall, P.B. . Wang, W. . Izon, G. . Jiang, H.-S. . Lai, X.-L. . Sun, Y.-D. . Newton, R.J. . Shao, L.-Y. . Védrine, S. . Cope, H. . 2010-06-01. The mid-Capitanian (Middle Permian) mass extinction and carbon isotope record of South China. Palaeogeography, Palaeoclimatology, Palaeoecology. en. 292. 1–2. 282–294. 10.1016/j.palaeo.2010.03.056. 2010PPP...292..282B . 0031-0182.
40. 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. Journal of Vertebrate Paleontology. en. 18. 3. 602–611. 10.1080/02724634.1998.10011087. 1998JVPal..18..602R . 0272-4634.
41. 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. Lethaia. en. 34. 4. 249–259. 10.1111/j.1502-3931.2001.tb00053.x. 0024-1164.
42. 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?. Proceedings of the Royal Society of London B: Biological Sciences. en. 274. 1627. 2829–2834. 10.1098/rspb.2007.0803. 0962-8452. 17848370. 2288685.
43. 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.
44. Ray. Sanghamitra. Chinsamy. Anusuya. 2004-03-25. Diictodon feliceps(Therapsida, Dicynodontia): bone histology, growth, and biomechanics. Journal of Vertebrate Paleontology. en. 24. 1. 180–194. 10.1671/1914-14. 2004JVPal..24..180R . 86189707. 0272-4634.
45. Angielczyk. Kenneth D.. Sullivan. Corwin. 2008-09-12. Diictodon feliceps(Owen, 1876), a dicynodont (Therapsida, Anomodontia) species with a Pangaean distribution. Journal of Vertebrate Paleontology. en. 28. 3. 788–802. 10.1671/0272-4634(2008)28[788:dfoadt]2.0.co;2. 85770120 . 0272-4634.
46. Benton. M. J.. 2012-03-02. No gap in the Middle Permian record of terrestrial vertebrates. Geology. en. 40. 4. 339–342. 10.1130/G32669.1. 2012Geo....40..339B. 0091-7613.
47. Damiani, R. J.. 2004-01-01. Temnospondyls from the Beaufort Group (Karoo Basin) of South Africa and Their Biostratigraphy. Gondwana Research. en. 7. 1. 165–173. 10.1016/S1342-937X(05)70315-4. 2004GondR...7..165D. 1342-937X.
48. Web site: Biostratigraphy of the Tapinocephalus Assemblage Zone (Beaufort Group, Karoo Supergroup), South Africa . Geoscienceworld. 11 September 2022.
49. Marsicano, Claudia & Latimer, Elizabeth & Rubidge, Bruce & Smith, Roger. (2017). The Rhinesuchidae and early history of the Stereospondyli (Amphibia: Temnospondyli) at the end of the Palaeozoic. Zoological Journal of the Linnean Society. 181. 10.1093/zoolinnean/zlw032.
50. Bender, P.A. (2005). A new deep-bodied Late Permian actinopterygian fish from the Beaufort Group, South Africa.
51. Bruce S. Rubidge, Michael O. Day, Julien Benoit, First record of the rare dicynodont Colobodectes from the southern Karoo Basin of South Africa has implications for middle Permian continental biostratigraphy, Journal of African Earth Sciences, Volume 208, 2023, 105097, ISSN 1464-343X, https://doi.org/10.1016/j.jafrearsci.2023.105097.
52. Duhamel . A. . Benoit . J. . Wynd . B. . Wright . A. M. . Rubidge . B. . 2024 . Redescription of three basal anomodonts: a phylogenetic reassessment of the holotype of Eodicynodon oelofseni (NMQR 2913) . Frontiers in Earth Science . 11 . 1220341 . 10.3389/feart.2023.1220341 . free. 2024FrEaS..1120341D .
53. Boonstra, L. D., 1969, The fauna of the Tapinocephalus zone (Beaufort beds of the Karoo): Annals of the South African Museum, v. 56, part 1, p. 1-73.
54. Reisz, Robert & Dilkes, David. (1992). The taxonomic position of Anningia megalops, a small amniote from the Permian of South Africa. Canadian Journal of Earth Sciences. 29. 1605-1608. 10.1139/e92-126. Anningia megalops Broom, 1927 is based upon a poorly preserved, incomplete skull and was interpreted originally as an intermediate form between therapsids and primitive nontherapsid synapsids (pelycosaurs). Restudy of the type specimen indicates that A. megalops is a nondiagnosable primitive synapsid and is, therefore, declared to be a nomen vanum.
55. 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. Science. en. 331. 6024. 1603–1605. 10.1126/science.1200305. 21436452. 2011Sci...331.1603C. 8178585. 0036-8075.
56. 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. Proceedings of the National Academy of Sciences. en. 109. 5. 1584–1588. 10.1073/pnas.1115975109. 0027-8424. 22307615. 3277192. 2012PNAS..109.1584C. free.
57. 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. Journal of Vertebrate Paleontology. en. 34. 4. 980–986. 10.1080/02724634.2013.826669. 2014JVPal..34..980S . 128431441. 0272-4634.
58. Book: The Nonmarine Permian: Bulletin 30. Lucas. Spencer G.. Zeigler. Kate E.. 2005. New Mexico Museum of Natural History and Science. en.