Daptocephalus Assemblage Zone

Last updated
Daptocephalus Assemblage Zone
Stratigraphic range: Changhsingian
~254.5–251  Ma
Ꞓ
O
S
D
C
P
T
J
K
Pg
N
↓
Daptocephalus leoniceps.jpg
Daptocephalus leoniceps
Type Biozone
Unit of Beaufort Group within Adelaide Supgroup
Sub-unitsUpper Teekloof Formation west of 24°E
Balfour Formation east of 24°E
Underlies Lystrosaurus Assemblage Zone
Overlies Cistecephalus Assemblage Zone
Thicknessup to 1,640.42 ft (500.00 m)
Location
Location Karoo Basin
Region Northern & Eastern Cape, Free State
CountryFlag of South Africa.svg  South Africa
Type section
Named for Daptocephalus
Named by James Kitching, Bruce Rubidge, Pia Viglietti

The Daptocephalus Assemblage Zone is a tetrapod assemblage zone or biozone found in the Adelaide Subgroup of the Beaufort Group, a majorly fossiliferous and geologically important Group of the Karoo Supergroup in South Africa. [1] [2] [3] [4] This biozone has outcrops located in the upper Teekloof Formation west of 24°E, the majority of the Balfour Formation east of 24°E, and the Normandien Formation in the north. It has numerous localities which are spread out from Colesberg in the Northern Cape, Graaff-Reniet to Mthatha in the Eastern Cape, and from Bloemfontein to Harrismith in the Free State. [3] The Daptocephalus Assemblage Zone is one of eight biozones found in the Beaufort Group and is considered Late Permian (Lopingian) in age. Its contact with the overlying Lystrosaurus Assemblage Zone marks the Permian-Triassic boundary. [5]

Contents

Previously known as the Dicynodon Assemblage Zone, the name of the biozone refers to Daptocephalus , a medium-sized dicynodont therapsid. It is characterized by the presence of this species in co-occurrence with Theriognathus microps , and Dicynodon lacerticeps. [6]

History

The first fossils to be found in the Beaufort Group rocks that encompass the current eight biozones were discovered by Andrew Geddes Bain in 1856. [7] However, it was not until 1892 that it was observed that the geological strata of the Beaufort Group could be differentiated based on their fossil taxa. The initial undertaking was done by Harry Govier Seeley who subdivided the Beaufort Group into three biozones, [8] which he named (from oldest to youngest):

These proposed biozones Seeley named were subdivided further by Robert Broom between 1906 and 1909. [9] Broom proposed the following biozones (from oldest to youngest):

These biozone divisions were approved by paleontologists of the time and were left largely unchanged for several decades. [10] The Daptocephalus Assemblage Zone was first named after the dicynodont Daptocephlaus leoniceps by James Kitching due to the high prevalence, and localized appearance, of this species. [11] [12] However, the name of the biozone was changed to the Dicynodon Assemblage Zone as it was argued that Daptocephalus was in fact a juvenile of Dicynodon . [13] [14] [15] In addition it was thought that Dicynodon was a more suitable taxon for global biostratigraphic correlation of other Karoo-aged basins, namely to those in Zambia, Tanzania, China, and Russia. In recent years, with new paleontological finds and updated logging of geological formations and biostratigraphy of the Karoo Basin, it was found that there has been some taxonomic confusion with Dicynodon fossils. [16] In addition, recent taxonomic studies have shown that Daptocephalus is indeed its own species, and is only found within the confines of the biozone. [3] Subsequently it was renamed the Daptocephalus Assemblage Zone.

Lithology

The Daptocephalus Assemblage Zone is located only in the upper Balfour formation and lower Normandien formation east of 24°E. These formations all fall within the Adelaide Subgroup of the Beaufort Group, sediments of which were formed in a large retroarc foreland basin in south-western Gondwana. [5] The biozone is subdivided into the lower Daptocephalus-Theriognathus subzone and the upper Lystrosaurus-Moschorhinus subzone. This satisfies the appearance of Lystrosaurus maccaigi below the Lystrosaurus Assemblage Zone boundary, [2] and the disappearance of the lower subzone taxa Theriognathus , Dicynodon , and Procynosuchus delaharpeae .

At the time of sedimentary deposition, the Karoo retroarc foreland system was in an overfilled phase, and purely terrestrial sediments occupied the Karoo Basin at this time. Two fining-upward sequences are observed in the sedimentary stratigraphy of Daptocephalus biozone, bounded by a second-order subaerial unconformity. These sedimentary rocks comprise greenish-grey mudrock with siltstone lenses in the lower to middle sections of the biozone, [1] [5] [3] which are indicative of a low-energy fluvial environments with meandering rivers. It is in these rocks that fossils are most commonly found. As the biozone reaches its termination, its contact with the overlying Katberg Formation marks a sharp change in the lithology. The sedimentary rocks change to being sandstone-rich with these sandstone bodies commonly appearing within outcrops of brownish-red shale and reddish mudstone. [17] The appearance and proliferation of these sandstone deposits marks the change to braided river systems where sands were only deposited [17] with the finer sediments being washed further downstream. [5]

Fossil abundance and preservation quality does not change across the boundary, however, species abundance does due to the extinction event, and also the preservational style of the fossils. More isolated skulls are found in the Permian, whereas in the earliest Triassic, curled up complete skeletons are more common as are bonebeds. [18] [2] These lithological and taphonomic changes are used as evidence for the sudden drying of the climate associated with the Permian-Triassic extinction event. [5] [19] [20] [18]

Paleontology

The lower to middle zones of the Daptocephlaus Assemblage Zone display a great diversity of vertebrate fauna. These include its current type species Daptocephalus and other dicynodonts such as the ubiquitous Diictodon , Dinanomodon , and Pristerodon . [1] [6] [21] Various species of burnetiamorph Biarmosuchians and Rubidgenae Gorgonopsians are also found. [1] [22] [23] [24] Therocephalian species such as Moschorhinus kitchingi and the earliest cynodont Charassognathus gracilis also appear. Parareptile species, namely captorhinids, [25] [26] the Younginiforme Youngina , [27] and a variety of temnospondyl amphibians, [13] fishes, and plant fossils such as Glossopteris are likewise found. [28] The upper zones as the Permian-Triassic boundary approaches, there is a marked drop in species diversity as the Permian-Triassic extinction event began to take its course. [29] [30] [31]

Age and correlations

The Daptocephalus Assemblage Zone dates to approximately 254.5 to 251 Ma, and correlates with the Kutuluksaya and Kulchomovskaya Formations of Russia, [32] and with the lower Buena Vista Formation of the Paraná Basin, South America. [33]

See also

Related Research Articles

<i>Robertia</i> Extinct genus of dicynodonts

Robertia is an extinct genus of small herbivorous dicynodonts from the Middle to Late Permian of South Africa, between 260 and 265 million years ago. It is a monospecific genus, consisting of the type-species R. broomiana, which was classified by Lieuwe Dirk Boonstra in 1948 and named in honor of Robert Broom for his study of South African mammal-like reptiles.

<i>Diictodon</i> Extinct genus of dicynodonts

Diictodon is an extinct genus of pylaecephalid dicynodont that lived during the Late Permian period, approximately 255 million years ago. Fossils have been found in the Cistecephalus Assemblage Zone of the Madumabisa Mudstone of the Luangwa Basin in Zambia and the Tropidostoma Assemblage Zone of the Teekloof Formation, Tapinocephalus Assemblage Zone of the Abrahamskraal Formation, Dicynodon Assemblage Zone of the Balfour Formation, Cistecephalus Assemblage Zone of the Middleton or Balfour Formation of South Africa and the Guodikeng Formation of China. Roughly half of all Permian vertebrate specimens found in South Africa are those of Diictodon. This small herbivorous animal was one of the most successful synapsids in the Permian period.

<span class="mw-page-title-main">Beaufort Group</span> Third of the main subdivisions of the Karoo Supergroup in South Africa

The Beaufort Group is the third of the main subdivisions of the Karoo Supergroup in South Africa. It is composed of a lower Adelaide Subgroup and an upper Tarkastad Subgroup. It follows conformably after the Ecca Group and unconformably underlies the Stormberg Group. Based on stratigraphic position, lithostratigraphic and biostratigraphic correlations, palynological analyses, and other means of geological dating, the Beaufort Group rocks are considered to range between Middle Permian (Wordian) to Early Triassic (Anisian) in age.

<i>Tapinocephalus</i> Assemblage Zone

The Tapinocephalus Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the middle Abrahamskraal Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. The thickest outcrops, reaching approximately 2,000 metres (6,600 ft), occur from Merweville and Leeu-Gamka in its southernmost exposures, from Sutherland through to Beaufort West where outcrops start to only be found in the south-east, north of Oudshoorn and Willowmore, reaching up to areas south of Graaff-Reinet. Its northernmost exposures occur around the towns Fraserburg and Victoria West. The Tapinocephalus Assemblage Zone is the second biozone of the Beaufort Group.

<i>Cistecephalus</i> Assemblage Zone

The Cistecephalus Assemblage Zone is a tetrapod assemblage zone or biozone found in the Adelaide Subgroup of the Beaufort Group, a majorly fossiliferous and geologically important geological group of the Karoo Supergroup in South Africa. This biozone has outcrops located in the Teekloof Formation north-west of Beaufort West in the Western Cape, in the upper Middleton and lower Balfour Formations respectively from Colesberg of the Northern Cape to east of Graaff-Reinet in the Eastern Cape. The Cistecephalus Assemblage Zone is one of eight biozones found in the Beaufort Group, and is considered to be Late Permian in age.

<i>Lystrosaurus</i> Assemblage Zone

The Lystrosaurus Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the upper Adelaide and lower Tarkastad Subgroups of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. This biozone has outcrops in the south central Eastern Cape and in the southern and northeastern Free State. The Lystrosaurus Assemblage Zone is one of eight biozones found in the Beaufort Group, and is considered to be Early Triassic in age.

<i>Cynognathus</i> Assemblage Zone Biozone which correlates to the Burgersdorp Formation of the Beaufort Group

The Cynognathus Assemblage Zone is a tetrapod biozone utilized in the Karoo Basin of South Africa. It is equivalent to the Burgersdorp Formation, the youngest lithostratigraphic formation in the Beaufort Group, which is part of the fossiliferous and geologically important Karoo Supergroup. The Cynognathus Assemblage Zone is the youngest of the eight biozones found in the Beaufort Group, and is considered to be late Early Triassic (Olenekian) to early Middle Triassic (Anisian) in age. The name of the biozone refers to Cynognathus crateronotus, a large and carnivorous cynodont therapsid which occurs throughout the entire biozone.

<i>Pristerognathus</i> Assemblage Zone

The Pristerognathus Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the upper Abrahamskraal Formation and lowermost Teekloof Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. The thickest outcrops, reaching not more than 300 metres (980 ft), occur just east of Sutherland through to Beaufort West in the south and Victoria West in the north. Exposures are also found west of Colesberg and south of Graaff-Reinet. The Pristerognathus Assemblage Zone is the third biozone of the Beaufort Group.

<i>Tropidostoma</i> Assemblage Zone

The Tropidostoma Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the lower Teekloof Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. The thickest outcrops, reaching approximately 240 metres (790 ft), occur from east of Sutherland through to Beaufort West and Victoria West, to areas south of Graaff-Reinet. Its northernmost exposures occur west/north-west of Colesberg. The Tropidostoma Assemblage Zone is the fourth biozone of the Beaufort Group.

<i>Eodicynodon</i> Assemblage Zone

The Eodicynodon Assemblage Zone is a tetrapod assemblage zone or biozone which correlates to the Abrahamskraal Formation, Adelaide Subgroup of the Beaufort Group, a fossiliferous and geologically important geological Group of the Karoo Supergroup in South Africa. The thickest outcrops, reaching approximately 620 metres (2,030 ft), occur south-east of Sutherland, north of Prince Albert, and south-east of Beaufort West. The Eodicynodon Assemblage Zone is the lowermost biozone of the Beaufort Group.

<i>Daptocephalus</i> Extinct genus of dicynodonts

Daptocephalus is an extinct genus of dicynodont synapsid, which was found in Late Permian strata, in a biozone known precisely for the presence of fossils of this dicynodont, the Daptocephalus Assemblage Zone, in the Karoo Basin in South Africa. An additional species, D. huenei, is known from the Usili Formation in Tanzania and was formerly assigned to the genus Dicynodon before a study in 2019 recognised that the type specimen belonged to Daptocephalus.

Platycraniellus is an extinct genus of carnivorous cynodonts from the Early Triassic. It is known from the Lystrosaurus Assemblage Zone of the Normandien Formation in South Africa. P. elegans is the only species in this genus based on the holotype specimen from the Ditsong National Museum of Natural History in Pretoria, South Africa. Due to limited fossil records for study, Platycraniellus has only been briefly described a handful of times.

<i>Pelanomodon</i> Extinct genus of dicynodonts

Pelanomodon is an extinct genus of dicynodont therapsids that lived in the Late Permian period. Fossil evidence of this genus is principally found in the Karoo Basin of South Africa, in the Dicynodon Assemblage Zone. Lack of fossil record after the Late Permian epoch suggests that Pelanomodon fell victim to the Permian-Triassic extinction event.

<i>Tropidostoma</i> Extinct genus of dicynodonts

Tropidostoma is a medium-sized herbivorous oudenodontid dicynodont therapsid that lived during the Late Permian (Lopingian) period in South Africa. The first Tropidostoma fossil was described by Harry Govier Seeley in 1889. Later two subspecies were identified. Tropidostoma fossils are an index fossil in a biozone of the Karoo Basin known as the Tropidostoma Assemblage Zone. This biozone is characterized by the presence of this species in association with another dicynodont species, Endothiodon uniseries.

<i>Langbergia</i> Extinct genus of cynodonts

Langbergia is an extinct genus of trirachodontid cynodont from the Early Triassic of South Africa. The type and only species L. modisei was named in 2006 after the farm where the holotype was found, Langberg 566. Langbergia was found in the Burgersdorp Formation in the Beaufort Group, a part of the Cynognathus Assemblage Zone. The closely related trirachodontids Trirachodon and Cricodon were found in the same area.

<span class="mw-page-title-main">Abrahamskraal Formation</span> Geological formation of the Beaufort Group in South Africa

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.

<span class="mw-page-title-main">Balfour Formation</span> Geological formation in the Beaufort Group of South Africa

The Balfour Formation is a geological formation that is found in the Beaufort Group, a major geological group that forms part of the greater Karoo Supergroup in South Africa. The Balfour Formation is the uppermost formation of the Adelaide Subgroup which contains all the Late Permian - Early Triassic aged biozones of the Beaufort Group. Outcrops and exposures of the Balfour Formation are found from east of 24 degrees in the highest mountainous escarpments between Beaufort West and Fraserburg, but most notably in the Winterberg and Sneeuberg mountain ranges near Cradock, the Baviaanskloof river valley, Graaff-Reniet and Nieu Bethesda in the Eastern Cape, and in the southern Free State province.

<span class="mw-page-title-main">Katberg Formation</span> Geological formation in the Beaufort Group of the Karoo Supergroup in South Africa

The Katberg Formation is a geological formation that is found in the Beaufort Group, a major geological group that forms part of the greater Karoo Supergroup in South Africa. The Katberg Formation is the lowermost geological formation of the Tarkastad Subgroup which contains the Lower to Middle Triassic-aged rocks of the Beaufort Group. Outcrops and exposures of the Katberg Formation are found east of 24 degrees on wards and north of Graaff-Reniet, Nieu Bethesda, Cradock, Fort Beaufort, Queensdown, and East London in the south, and ranges as far north as Harrismith in deposits that form a ring around the Drakensberg mountain ranges.

<span class="mw-page-title-main">Teekloof Formation</span> Late Permian geological formation that forms part of the Beaufort Group of South Africa

The Teekloof Formation is a geological formation that forms part of the Beaufort Group, one of the five geological groups that comprises the Karoo Supergroup in South Africa. The Teekloof Formation is the uppermost formation of Adelaide Subgroup deposits West of 24ºE and contains Middle to Late Permian-aged deposits and four biozones of the Beaufort Group. It overlies the Abrahamskraal Formation. The Teekloof Formation does not underlie other units other than the younger Karoo dolerites and sills that relate to the emplacement of the Early Jurassic Drakensberg Group to the east. Outcrops and exposures of the Teekloof Formation range from Sutherland through the mountain escarpments between Fraserburg and Beaufort West. The northernmost localities of the Teekloof Formation are found by Loxton, Victoria West and Richmond.

<i>Thliptosaurus</i> Extinct genus of dicynodonts

Thliptosaurus is an extinct genus of small kingoriid dicynodont from the latest Permian period of the Karoo Basin in KwaZulu-Natal, South Africa. It contains the type and only known species T. imperforatus. Thliptosaurus is from the upper Daptocephalus Assemblage Zone, making it one of the youngest Permian dicynodonts known, living just prior to the Permian mass extinction. It also represents one of the few small bodied dicynodonts to exist at this time, when most other dicynodonts had large body sizes and many small dicynodonts had gone extinct. The unexpected discovery of Thliptosaurus in a region of the Karoo outside of the historically sampled localities suggests that it may have been part of an endemic local fauna not found in these historic sites. Such under-sampled localities may contain 'hidden diversities' of Permian faunas that are unknown from traditional samples. Thliptosaurus is also unusual for dicynodonts as it lacks a pineal foramen, suggesting that it played a much less important role in thermoregulation than it did for other dicynodonts.

References

  1. 1 2 3 4 Rubidge, B. S. (1995). Biostratigraphy of the Beaufort Group (Karoo Supergroup). Biostratigraphic series.
  2. 1 2 3 Botha, Jennifer; Smith, Roger M. H. (2007). "Lystrosaurus species composition across the Permo-Triassic boundary in the Karoo Basin of South Africa". Lethaia. 40 (2): 125–137. doi:10.1111/j.1502-3931.2007.00011.x. ISSN   0024-1164.
  3. 1 2 3 4 Viglietti, Pia A.; Smith, Roger M. H.; Angielczyk, Kenneth D.; Kammerer, Christian F.; Fröbisch, Jörg; Rubidge, Bruce S. (2016). "The Daptocephalus Assemblage Zone (Lopingian), South Africa: A proposed biostratigraphy based on a new compilation of stratigraphic ranges". Journal of African Earth Sciences. 113: 153–164. Bibcode:2016JAfES.113..153V. doi:10.1016/j.jafrearsci.2015.10.011. ISSN   1464-343X.
  4. ↑ Lucas, S. G. (2009). "Timing and magnitude of tetrapod extinctions across the Permo-Triassic boundary". Journal of Asian Earth Sciences. 36 (6): 491–502. Bibcode:2009JAESc..36..491L. doi:10.1016/j.jseaes.2008.11.016. ISSN   1367-9120.
  5. 1 2 3 4 5 Smith, Roger M. H. (1995). "Changing fluvial environments across the Permian-Triassic boundary in the Karoo Basin, South Africa and possible causes of tetrapod extinctions". Palaeogeography, Palaeoclimatology, Palaeoecology. 117 (1–2): 81–104. Bibcode:1995PPP...117...81S. doi:10.1016/0031-0182(94)00119-S. ISSN   0031-0182.
  6. 1 2 van der Walt, Merrill; Day, Michael; Rubidge, Bruce; Cooper, Antony K.; Netterberg, Inge (2010). "A new GIS-based biozone map of the Beaufort Group (Karoo Supergroup), South Africa". Palaeontologia Africana. ISSN   0078-8554.
  7. ↑ Bain, Andrew Geddes (1845-02-01). "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. hdl:2027/uc1.c034667778. ISSN   0370-291X. S2CID   128602890.
  8. ↑ Seeley, H. G. (1895). "Researches on the Structure, Organization, and Classification of the Fossil Reptilia. Part IX., Section 4. On the Gomphodontia". Philosophical Transactions of the Royal Society of London B. 186: 1–57. Bibcode:1895RSPTB.186....1S. doi: 10.1098/rstb.1895.0001 . JSTOR   91793.
  9. ↑ Broom, R. (January 1906). "V.—On the Permian and Triassic Faunas of South Africa". Geological Magazine. 3 (1): 29–30. Bibcode:1906GeoM....3...29B. doi:10.1017/S001675680012271X. ISSN   1469-5081. S2CID   129265956.
  10. ↑ 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. Bibcode:1914GeoM....1..203W. doi:10.1017/S001675680019675X. ISSN   1469-5081. S2CID   130747924.
  11. ↑ 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).
  12. ↑ Kitching, J. W. (1977). The distribution of the Karroo vertebrate fauna: with special reference to certain genera and the bearing of this distribution on the zoning of the Beaufort Beds, Bernard Price Institute for Palaeontological Research, University of the Witwatersrand.
  13. 1 2 Damiani, Ross J. (2004). "Temnospondyls from the Beaufort Group (Karoo Basin) of South Africa and Their Biostratigraphy". Gondwana Research. 7 (1): 165–173. Bibcode:2004GondR...7..165D. doi:10.1016/s1342-937x(05)70315-4. ISSN   1342-937X.
  14. ↑ 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.
  15. ↑ Hancox, P. J.; Rubidge, B. S. (2001). "Breakthroughs in the biodiversity, biogeography, biostratigraphy, and basin analysis of the Beaufort group". Journal of African Earth Sciences. 33 (3–4): 563–577. Bibcode:2001JAfES..33..563H. doi:10.1016/S0899-5362(01)00081-1. ISSN   1464-343X.
  16. ↑ Kammerer, Christian F.; Angielczyk, Kenneth D.; Fröbisch, Jörg (2011). "A comprehensive taxonomic revision of Dicynodon (Therapsida, Anomodontia) and its implications for dicynodont phylogeny, biogeography, and biostratigraphy". Journal of Vertebrate Paleontology. 31 (sup1): 1–158. doi:10.1080/02724634.2011.627074. ISSN   0272-4634. S2CID   84987497.
  17. 1 2 Hiller, Norton; Stavrakis, Nicholas (1984-02-01). "Permo-Triassic fluvial systems in the southeastern Karoo Basin, South Africa". Palaeogeography, Palaeoclimatology, Palaeoecology. 45 (1): 1–21. Bibcode:1984PPP....45....1H. doi:10.1016/0031-0182(84)90106-8. ISSN   0031-0182.
  18. 1 2 Smith, R. M. H.; Botha-Brink, J. (2014). "Anatomy of a mass extinction: Sedimentological and taphonomic evidence for drought-induced die-offs at the Permo-Triassic boundary in the main Karoo Basin, South Africa". Palaeogeography, Palaeoclimatology, Palaeoecology. 396: 99–118. doi:10.1016/j.palaeo.2014.01.002. ISSN   0031-0182.
  19. ↑ MacLeod, Kenneth G.; Smith, Roger M. H.; Koch, Paul L.; Ward, Peter D. (2000). "Timing of mammal-like reptile extinctions across the Permian-Triassic boundary in South Africa". Geology. 28 (3): 227. Bibcode:2000Geo....28..227M. doi:10.1130/0091-7613(2000)28<227:TOMREA>2.0.CO;2. ISSN   0091-7613.
  20. ↑ Benton, Michael J.; Twitchett, Richard J. (2003-07-01). "How to kill (almost) all life: the end-Permian extinction event". Trends in Ecology & Evolution. 18 (7): 358–365. doi:10.1016/S0169-5347(03)00093-4. ISSN   0169-5347.
  21. ↑ Kammerer, Christian F.; Angielczyk, Kenneth D.; Fröbisch, Jörg (2011-12-14). "A comprehensive taxonomic revision of Dicynodon (Therapsida, Anomodontia) and its implications for dicynodont phylogeny, biogeography, and biostratigraphy". Journal of Vertebrate Paleontology. 31 (sup1): 1–158. doi:10.1080/02724634.2011.627074. ISSN   0272-4634. S2CID   84987497.
  22. ↑ Kammerer, Christian F. (2016-01-26). "Systematics of the Rubidgeinae (Therapsida: Gorgonopsia)". PeerJ. 4: e1608. doi: 10.7717/peerj.1608 . ISSN   2167-8359. PMC   4730894 . PMID   26823998.
  23. ↑ 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. 1 (2): 201–221. doi:10.1002/spp2.1012. ISSN   2056-2802. S2CID   128762256.
  24. ↑ Lucas, Spencer G.; Zeigler, Kate E. (2005-01-01). The Nonmarine Permian: Bulletin 30. New Mexico Museum of Natural History and Science.
  25. ↑ Ray, Sanghamitra (1999-07-01). "Permian reptilian fauna from the Kundaram Formation, Pranhita-Godavari Valley, India". Journal of African Earth Sciences. 29 (1): 211–218. Bibcode:1999JAfES..29..211R. doi:10.1016/S0899-5362(99)00090-1. ISSN   1464-343X.
  26. ↑ Reisz, Robert R.; Laurin, Michel (1991). "Owenetta and the origin of turtles". Nature. 349 (6307): 324–326. Bibcode:1991Natur.349..324R. doi:10.1038/349324a0. ISSN   0028-0836. S2CID   350380.
  27. ↑ Gardner, Nicholas M.; Holliday, Casey M.; O'Keefe, F. Robin (2010). "The Braincase of Youngina capensis (Reptilia, Diapsida): New Insights from High-Resolution CT Scanning of the Holotype". Marshall Digital Scholar.
  28. ↑ Prevec, Rose; Gastaldo, Robert A.; Neveling, Johann; Reid, Samuel B.; Looy, Cindy V. (2010-06-15). "An autochthonous glossopterid flora with latest Permian palynomorphs and its depositional setting in the Dicynodon Assemblage Zone of the southern Karoo Basin, South Africa". Palaeogeography, Palaeoclimatology, Palaeoecology. 292 (3–4): 391–408. Bibcode:2010PPP...292..391P. doi:10.1016/j.palaeo.2010.03.052. ISSN   0031-0182.
  29. ↑ Smith, Roger M.H.; Ward, Peter D. (2001). "Pattern of vertebrate extinctions across an event bed at the Permian-Triassic boundary in the Karoo Basin of South Africa". Geology. 29 (12): 1147. Bibcode:2001Geo....29.1147S. doi:10.1130/0091-7613(2001)029<1147:POVEAA>2.0.CO;2. ISSN   0091-7613.
  30. ↑ Botha, J.; Smith, R. M. H. (2006). "Rapid vertebrate recuperation in the Karoo Basin of South Africa following the End-Permian extinction". Journal of African Earth Sciences. 45 (4–5): 502–514. Bibcode:2006JAfES..45..502B. doi:10.1016/j.jafrearsci.2006.04.006. ISSN   1464-343X.
  31. ↑ Twitchett, Richard J. (2007-08-20). "The Lilliput effect in the aftermath of the end-Permian extinction event". Palaeogeography, Palaeoclimatology, Palaeoecology. 252 (1–2): 132–144. Bibcode:2007PPP...252..132T. doi:10.1016/j.palaeo.2006.11.038. ISSN   0031-0182.
  32. ↑ "Magnetostratigraphy - Background to stratigraphy across the PTB in Russia". Archived from the original on 2019-02-16. Retrieved 2019-03-15.
  33. ↑ Ezcurra, 2016, p.8

Bibliography

This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.