The Capitanian mass extinction event, also known as the end-Guadalupian extinction event, [2] the Guadalupian-Lopingian boundary mass extinction, [3] the pre-Lopingian crisis, [4] or the Middle Permian extinction, was an extinction event that predated the end-Permian extinction event. The mass extinction occurred during a period of decreased species richness and increased extinction rates near the end of the Middle Permian, also known as the Guadalupian epoch. It is often called the end-Guadalupian extinction event because of its initial recognition between the Guadalupian and Lopingian series; however, more refined stratigraphic study suggests that extinction peaks in many taxonomic groups occurred within the Guadalupian, in the latter half of the Capitanian age. [5] The extinction event has been argued to have begun around 262 million years ago with the Late Guadalupian crisis, though its most intense pulse occurred 259 million years ago in what is known as the Guadalupian-Lopingian boundary event. [6]
Having historically been considered as part of the end-Permian extinction event, and only viewed as separate relatively recently,[ when? ] [7] this mass extinction is believed to be the third largest of the Phanerozoic in terms of the percentage of species lost, after the end-Permian and Late Ordovician mass extinctions, respectively, [8] while being the fifth worst in terms of ecological severity. [9] The global nature of the Capitanian mass extinction has been called into question by some palaeontologists as a result of some analyses finding it to have affected only low-latitude taxa in the Northern Hemisphere. [10]
In the aftermath of Olson's Extinction, global diversity rose during the Capitanian. This was probably the result of disaster taxa replacing extinct guilds. The Capitanian mass extinction greatly reduced disparity (the range of different guilds); eight guilds were lost. It impacted the diversity within individual communities more severely than the Permian–Triassic extinction event. [11] Although faunas began recovery immediately after the Capitanian extinction event, [12] [13] rebuilding complex trophic structures and refilling guilds, [11] diversity and disparity fell further until the Permian–Triassic boundary. [14]
The impact of the Capitanian extinction event on marine ecosystems is still heavily debated by palaeontologists. Early estimates indicated a loss of marine invertebrate genera between 35 and 47%, [15] [16] while an estimate published in 2016 suggested a loss of 33–35% of marine genera when corrected for background extinction, the Signor–Lipps effect and clustering of extinctions in certain taxa. [17] The loss of marine invertebrates during the Capitanian mass extinction was comparable in magnitude to the Cretaceous–Paleogene extinction event. [18] Some studies have considered it the third or fourth greatest mass extinction in terms of the proportion of marine invertebrate genera lost; a different study found the Capitanian extinction event to be only the ninth worst in terms of taxonomic severity (number of genera lost) but found it to be the fifth worst with regard to its ecological impact (i.e., the degree of taxonomic restructuring within ecosystems or the loss of ecological niches or even entire ecosystems themselves). [19]
Few published estimates for the impact on terrestrial ecosystems exist for the Capitanian mass extinction. Among vertebrates, Day and colleagues suggested a 74–80% loss of generic richness in tetrapods of the Karoo Basin in South Africa, [20] including the extinction of the dinocephalians. [21] In land plants, Stevens and colleagues found an extinction of 56% of plant species recorded in the mid-Upper Shihhotse Formation in North China, [22] which was approximately mid-Capitanian in age. 24% of plant species in South China went extinct. [23]
Although it is known that the Capitanian mass extinction occurred after Olson's Extinction and before the Permian–Triassic extinction event, [11] the exact age of the Capitanian mass extinction remains controversial. This is partly due to the somewhat circumstantial age of the Capitanian–Wuchiapingian boundary itself, which is currently estimated to be approximately 259.1 million years old, [20] [21] [24] but is subject to change by the Subcommission on Permian Stratigraphy of the International Commission on Stratigraphy. Additionally, there is a dispute regarding the severity of the extinction and whether the extinction in China happened at the same time as the extinction in Spitsbergen. [25] According to one study, the Capitanian mass extinction was not one discrete event but a continuous decline in diversity that began at the end of the Wordian. [26] Another study examining fossiliferous facies in Svalbard found no evidence for a sudden mass extinction, instead attributing local biotic changes during the Capitanian to the southward migration of many taxa through the Zechstein Sea. [27] Carbonate platform deposits in Hungary and Hydra show no sign of an extinction event at the end of the Capitanian; the extinction event there is recorded in the middle Capitanian. [28]
The volcanics of the Emeishan Traps, which are interbedded with tropical carbonate platforms of the Maokou Formation, are unique for preserving a mass extinction and the cause of that mass extinction. [23] Large phreatomagmatic eruptions occurred when the Emeishan Traps first started to erupt, leading to the extinction of fusulinacean foraminifera and calcareous algae. [29]
In the absence of radiometric ages directly constraining the extinction horizons themselves in the marine sections, most recent studies refrain from placing a number on its age, but based on extrapolations from the Permian timescale an age of approximately 260–262 Ma has been estimated; [20] [30] this fits broadly with radiometric ages from the terrestrial realm, assuming the two events are contemporaneous. Plant losses occurred either at the same time as the marine extinction or after it. [23]
The extinction of fusulinacean foraminifera in Southwest China was originally dated to the end of the Guadalupian, but studies published in 2009 and 2010 dated the extinction of these fusulinaceans to the mid-Capitanian. [31] Brachiopod and coral losses occurred in the middle of the Capitanian stage. [32] The extinction suffered by the ammonoids may have occurred in the early Wuchiapingian. [32]
The existence of change in tetrapod faunas in the mid-Permian has long been known in South Africa and Russia. In Russia, it corresponded to the boundary between what became known as the Titanophoneus Superzone and the Scutosaurus Superzone [33] and later the Dinocephalian Superassemblage and the Theriodontian Superassemblage, respectively. In South Africa, this corresponded to the boundary between the variously named Pareiasaurus , Dinocephalian or Tapinocephalus Assemblage Zone and the overlying assemblages. [34] [35] [36] [37] In both Russia and South Africa, this transition was associated with the extinction of the previously dominant group of therapsid amniotes, the dinocephalians, which led to its later designation as the dinocephalian extinction. [38] Post-extinction origination rates remained low through the Pristerognathus Assemblage Zone for at least 1 million years, which suggests that there was a delayed recovery of Karoo Basin ecosystems. [39]
After the recognition of a separate marine mass extinction at the end of the Guadalupian, the dinocephalian extinction was seen to represent its terrestrial correlate. [18] Though it was subsequently suggested that because the Russian Ischeevo fauna, which was considered the youngest dinocephalian fauna in that region, was constrained to below the Illawarra magnetic reversal and therefore had to have occurred in the Wordian stage, well before the end of the Guadalupian, [38] this constraint applied to the type locality only. The recognition of a younger dinocephalian fauna in Russia (the Sundyr Tetrapod Assemblage) [40] and the retrieval of biostratigraphically well-constrained radiometric ages via uranium–lead dating of a tuff from the Tapinocephalus Assemblage Zone of the Karoo Basin [20] [41] demonstrated that the dinocephalian extinction did occur in the late Capitanian, around 260 million years ago.
In the oceans, the Capitanian extinction event led to high extinction rates among ammonoids, corals and calcareous algal reef-building organisms, foraminifera, bryozoans, and brachiopods. It was more severe in restricted marine basins than in the open oceans. [42] It appears to have been particularly selective against shallow-water taxa that relied on photosynthesis or a photosymbiotic relationship; [43] many species with poorly buffered respiratory physiologies also became extinct. [44] [45] The extinction event led to a collapse of the reef carbonate factory in the shallow seas surrounding South China. [46] [47]
The ammonoids, which had been in a long-term decline for a 30 million year period since the Roadian, suffered a selective extinction pulse at the end of the Capitanian. [14] 75.6% of coral families, 77.8% of coral genera and 82.2% of coral species that were in Permian China were lost during the Capitanian mass extinction. [48] The Verbeekinidae, a family of large fusuline foraminifera, went extinct. [49]
87% of brachiopod species found at the Kapp Starostin Formation on Spitsbergen disappeared over a period of tens of thousands of years; though new brachiopod and bivalve species emerged after the extinction, the dominant position of the brachiopods was taken over by the bivalves. [50] Approximately 70% of other species found at the Kapp Starostin Formation also vanished. [51] The fossil record of East Greenland is similar to that of Spitsbergen; the faunal losses in Canada's Sverdrup Basin are comparable to the extinctions in Spitsbergen and East Greenland, but the post-extinction recovery that happened in Spitsbergen and East Greenland did not occur in the Sverdrup Basin. [30] Whereas rhynchonelliform brachiopods made up 99.1% of the individuals found in tropical carbonates in the Western United States, South China and Greece prior to the extinction, molluscs made up 61.2% of the individuals found in similar environments after the extinction. [52] 87% of brachiopod species and 82% of fusulinacean foraminifer species in South China were lost. [30] Although severe for brachiopods, the Capitanian extinction's impact on their diversity was nowhere near as strong as that of the later end-Permian extinction. [53]
Biomarker evidence indicates red algae and photoautotrophic bacteria dominated marine microbial communities. Significant turnovers in microbial ecosystems occurred during the Capitanian mass extinction, though they were smaller in magnitude than those associated with the end-Permian extinction. [54]
Most of the marine victims of the extinction were either endemic species of epicontinental seas around Pangaea that died when the seas closed, or were dominant species of the Paleotethys Ocean. [55] Evidence from marine deposits in Japan and Primorye suggests that mid-latitude marine life became affected earlier by the extinction event than marine organisms of the tropics. [56]
Whether and to what degree latitude affected the likelihood of taxa to go extinct remains disputed amongst palaeontologists. Whereas some studies conclude that the extinction event was a regional one limited to tropical areas, [10] others suggest that there was little latitudinal variation in extinction patterns. [57] A study examining foraminiferal extinctions in particular found that the Central and Western Palaeotethys experienced taxonomic losses of a lower magnitude than the Northern and Eastern Palaeotethys, which had the highest extinction magnitude. The same study found that Panthalassa's overall extinction magnitude was similar to that of the Central and Western Palaeotethys, but that it had a high magnitude of extinction of endemic taxa. [58]
This mass extinction marked the beginning of the transition between the Palaeozoic and Modern evolutionary faunas. [2] The brachiopod-mollusc transition that characterised the broader shift from the Palaeozoic to Modern evolutionary faunas has been suggested to have had its roots in the Capitanian mass extinction event, although other research has concluded that this may be an illusion created by taphonomic bias in silicified fossil assemblages, with the transition beginning only in the aftermath of the more cataclysmic end-Permian extinction. [59] After the Capitanian mass extinction, disaster taxa such as Earlandia and Diplosphaerina became abundant in what is now South China. [5] The initial recovery of reefs consisted of non-metazoan reefs: algal bioherms and algal-sponge reef buildups. This initial recovery interval was followed by an interval of Tubiphytes-dominated reefs, which in turn was followed by a return of metazoan, sponge-dominated reefs. [60] Overall, reef recovery took approximately 2.5 million years. [3]
Among terrestrial vertebrates, the main victims were dinocephalian therapsids, which were one of the most common elements of tetrapod fauna of the Guadalupian; only one dinocephalian genus survived the Capitanian extinction event. [18] The diversity of the anomodonts that lived during the late Guadalupian was cut in half by the Capitanian mass extinction. [61] Terrestrial survivors of the Capitanian extinction event were generally 20 kg (44 lb) to 50 kg (110 lb) and commonly found in burrows. [18]
It is believed that the extinction, which coincided with the beginning of a major negative δ13C excursion signifying a severe disturbance of the carbon cycle, [62] [23] was triggered by eruptions of the Emeishan Traps large igneous province, [63] [64] [22] basalt piles from which currently cover an area of 250,000 to 500,000 km2, although the original volume of the basalts may have been anywhere from 500,000 km3 to over 1,000,000 km3. [45] The age of the extinction event and the deposition of the Emeishan basalts are in good alignment. [65] [66] Reefs and other marine sediments interbedded among basalt piles indicate Emeishan volcanism initially developed underwater; terrestrial outflows of lava occurred only later in the large igneous province's period of activity. [67] These eruptions would have released high doses of toxic mercury; [68] [69] increased mercury concentrations are coincident with the negative carbon isotope excursion, indicating a common volcanic cause. [70] Coronene enrichment at the Guadalupian-Lopingian boundary further confirms the existence of massive volcanic activity; coronene can only form at extremely high temperatures created either by extraterrestrial impacts or massive volcanism, with the former being ruled out because of an absence of iridium anomalies coeval with mercury and coronene anomalies. [71] A large amount of carbon dioxide and sulphur dioxide is believed to have been discharged into the stratosphere of the Northern and Southern Hemispheres due to the equatorial location of the Emeishan Traps, leading to sudden global cooling and long-term global warming. [29] The Emeishan Traps discharged between 130 and 188 teratonnes of carbon dioxide in total, doing so at a rate of between 0.08 to 0.25 gigatonnes of carbon dioxide per year, making them responsible for an increase in atmospheric carbon dioxide that was both one of the largest and one of the most precipitous in the entire geological history of the Earth. [72] The rate of carbon dioxide emissions during the Capitanian mass extinction, though extremely abrupt, was nonetheless significantly slower than that during the end-Permian extinction, during which carbon dioxide levels rose five times faster according to one study. [73] Significant quantities of methane released by dikes and sills intruding into coal-rich deposits has been implicated as an additional driver of warming, [74] though this idea has been challenged by studies that instead conclude that the extinction was precipitated directly by the Emeishan Traps or by their interaction with platform carbonates. [75] [76] [77] The emissions of the Emeishan Traps may also have contributed to the downfall of the ozone shield, exposing the Earth's surface to a vastly increased flux of high-frequency solar radiation. [78]
Global warming resulting from the large igneous province's activity has been implicated as a cause of marine anoxia. [79] Two anoxic events, the middle Capitanian OAE-C1 and the end-Capitanian OAE-C2, occurred thanks to Emeishan volcanic activity. [80] Volcanic greenhouse gas release and global warming increased continental weathering and mineral erosion, which in turn has been propounded as a factor enhancing oceanic euxinia. [81] Euxinia may have been exacerbated even further by the increasing sluggishness of ocean circulation resulting from volcanically driven warming. [82] The initial hydrothermal nature of the Emeishan Traps meant that local marine life around South China would have been especially jeopardised by anoxia due to hyaloclastite development in restricted, fault-bounded basins. [67] Expansion of oceanic anoxia has been posited to have occurred slightly before the Capitanian extinction event itself by some studies, though it is probable that upwelling of anoxic waters prior to the mass extinction was a local phenomenon specific to South China. [83]
Because the ocean acts as a carbon sink absorbing atmospheric carbon dioxide, it is likely that the excessive volcanic emissions of carbon dioxide resulted in marine hypercapnia, which would have acted in conjunction with other killing mechanisms to further increase the severity of the biotic crisis. [84] The dissolution of volcanically emitted carbon dioxide in the oceans triggered ocean acidification, [30] [25] [50] which probably contributed to the demise of various calcareous marine organisms, particularly giant alatoconchid bivalves. [85] By virtue of the greater solubility of carbon dioxide in colder waters, ocean acidification was especially lethal in high latitude waters. [79] Furthermore, acid rain would have arisen as yet another biocidal consequence of the intense sulphur emissions produced by Emeishan Traps volcanism. [29] This resulted in soil acidification and a decline of terrestrial infaunal invertebrates. [86] Some researchers have cast doubt on whether significant acidification took place globally, concluding that the carbon cycle perturbation was too small to have caused a major worldwide drop in pH. [87]
Not all studies, however, have supported the volcanic warming hypothesis; analysis of δ13C and δ18O values from the tooth apatite of Diictodon feliceps specimens from the Karoo Supergroup shows a positive δ13C excursion and concludes that the end of the Capitanian was marked by massive aridification in the region, although the temperature remained largely the same, suggesting that global climate change did not account for the extinction event. [88] Analysis of vertebrate extinction rates in the Karoo Basin, specifically the upper Abrahamskraal Formation and lower Teekloof Formation, show that the large scale decrease in terrestrial vertebrate diversity coincided with volcanism in the Emeishan Traps, although robust evidence for a causal relationship between these two events remains elusive. [89] A 2015 study called into question whether the Capitanian mass extinction event was global in nature at all or merely a regional biotic crisis limited to South China and a few other areas, finding no evidence for terrestrial or marine extinctions in eastern Australia linked to the Emeishan Traps or to any proposed extinction triggers invoked to explain the biodiversity drop in low-latitudes of the Northern Hemisphere. [10]
The Capitanian mass extinction has been attributed to sea level fall, [90] with the widespread demise of reefs in particular being linked to this marine regression. [84] The Guadalupian-Lopingian boundary coincided with one of the most prominent first-order marine regressions of the Phanerozoic. [5] Evidence for abrupt sea level fall at the terminus of the Guadalupian comes from evaporites and terrestrial facies overlying marine carbonate deposits across the Guadalupian-Lopingian transition. [84] Additionally, a tremendous unconformity is associated with the Guadalupian-Lopingian boundary in many strata across the world. [91] The closure of the Sino-Mongolian Seaway at the end of the Capitanian has been invoked as a potential driver of Palaeotethyan biodiversity loss. [92]
Global drying, plate tectonics, and biological competition may have also played a role in the extinction. [5] [22] [48] [88] Potential drivers of extinction proposed as causes of end-Guadalupian reef decline include fluctuations in salinity and tectonic collisions of microcontinents. [84]
An extinction event is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp fall in the diversity and abundance of multicellular organisms. It occurs when the rate of extinction increases with respect to the background extinction rate and the rate of speciation. Estimates of the number of major mass extinctions in the last 540 million years range from as few as five to more than twenty. These differences stem from disagreement as to what constitutes a "major" extinction event, and the data chosen to measure past diversity.
The Permian is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period 298.9 million years ago (Mya), to the beginning of the Triassic Period 251.902 Mya. It is the sixth and last period of the Paleozoic Era; the following Triassic Period belongs to the Mesozoic Era. The concept of the Permian was introduced in 1841 by geologist Sir Roderick Murchison, who named it after the region of Perm in Russia.
Approximately 251.9 million years ago, the Permian–Triassicextinction event forms the boundary between the Permian and Triassic geologic periods, and with them the Paleozoic and Mesozoic eras. It is Earth's most severe known extinction event, with the extinction of 57% of biological families, 83% of genera, 81% of marine species and 70% of terrestrial vertebrate species. It is also the greatest known mass extinction of insects. It is the greatest of the "Big Five" mass extinctions of the Phanerozoic. There is evidence for one to three distinct pulses, or phases, of extinction.
The Late Ordovician mass extinction (LOME), sometimes known as the end-Ordovician mass extinction or the Ordovician-Silurian extinction, is the first of the "big five" major mass extinction events in Earth's history, occurring roughly 445 million years ago (Ma). It is often considered to be the second-largest known extinction event just behind the end-Permian mass extinction, in terms of the percentage of genera that became extinct. Extinction was global during this interval, eliminating 49–60% of marine genera and nearly 85% of marine species. Under most tabulations, only the Permian-Triassic mass extinction exceeds the Late Ordovician mass extinction in biodiversity loss. The extinction event abruptly affected all major taxonomic groups and caused the disappearance of one third of all brachiopod and bryozoan families, as well as numerous groups of conodonts, trilobites, echinoderms, corals, bivalves, and graptolites. Despite its taxonomic severity, the Late Ordovician mass extinction did not produce major changes to ecosystem structures compared to other mass extinctions, nor did it lead to any particular morphological innovations. Diversity gradually recovered to pre-extinction levels over the first 5 million years of the Silurian period.
The Late Devonian extinction consisted of several extinction events in the Late Devonian Epoch, which collectively represent one of the five largest mass extinction events in the history of life on Earth. The term primarily refers to a major extinction, the Kellwasser event, also known as the Frasnian-Famennian extinction, which occurred around 372 million years ago, at the boundary between the Frasnian age and the Famennian age, the last age in the Devonian Period. Overall, 19% of all families and 50% of all genera became extinct. A second mass extinction called the Hangenberg event, also known as the end-Devonian extinction, occurred 359 million years ago, bringing an end to the Famennian and Devonian, as the world transitioned into the Carboniferous Period.
The Guadalupian is the second and middle series/epoch of the Permian. The Guadalupian was preceded by the Cisuralian and followed by the Lopingian. It is named after the Guadalupe Mountains of New Mexico and Texas, and dates between 272.95 ± 0.5 – 259.1 ± 0.4 Mya. The series saw the rise of the therapsids, a minor extinction event called Olson's Extinction and a significant mass extinction called the end-Capitanian extinction event. The Guadalupian was previously known as the Middle Permian.
The Lopingian is the uppermost series/last epoch of the Permian. It is the last epoch of the Paleozoic. The Lopingian was preceded by the Guadalupian and followed by the Early Triassic.
In the geologic timescale, the Capitanian is an age or stage of the Permian. It is also the uppermost or latest of three subdivisions of the Guadalupian Epoch or Series. The Capitanian lasted between 264.28 and 259.51 million years ago. It was preceded by the Wordian and followed by the Wuchiapingian.
The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between 251.9 Ma and 247.2 Ma. Rocks from this epoch are collectively known as the Lower Triassic Series, which is a unit in chronostratigraphy. The Early Triassic is the oldest epoch of the Mesozoic Era. It is preceded by the Lopingian Epoch and followed by the Middle Triassic Epoch. The Early Triassic is divided into the Induan and Olenekian ages. The Induan is subdivided into the Griesbachian and Dienerian subages and the Olenekian is subdivided into the Smithian and Spathian subages.
In the geologic timescale, the Olenekian is an age in the Early Triassic epoch; in chronostratigraphy, it is a stage in the Lower Triassic series. It spans the time between 251.2 Ma and 247.2 Ma. The Olenekian is sometimes divided into the Smithian and the Spathian subages or substages. The Olenekian follows the Induan and is followed by the Anisian.
The late Paleozoic icehouse, also known as the Late Paleozoic Ice Age (LPIA) and formerly known as the Karoo ice age, was an ice age that began in the Late Devonian and ended in the Late Permian, occurring from 360 to 255 million years ago (Mya), and large land-based ice sheets were then present on Earth's surface. It was the second major icehouse period of the Phanerozoic, after the Late Ordovician Andean-Saharan glaciation.
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.
Anteosaurus is an extinct genus of large carnivorous dinocephalian synapsid. It lived at the end of the Guadalupian during the Capitanian age, about 265 to 260 million years ago in what is now South Africa. It is mainly known by cranial remains and few postcranial bones. Measuring 5–6 m (16–20 ft) long and weighing about 600 kg (1,300 lb), Anteosaurus was the largest known carnivorous non-mammalian synapsid and the largest terrestrial predator of the Permian period. Occupying the top of the food chain in the Middle Permian, its skull, jaws and teeth show adaptations to capture large prey like the giants titanosuchids and tapinocephalids dinocephalians and large pareiasaurs.
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. 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. 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.
The Emeishan Traps constitute a flood basalt volcanic province, or large igneous province, in south-western China, centred in Sichuan province. It is sometimes referred to as the Permian Emeishan Large Igneous Province or Emeishan Flood Basalts. Like other volcanic provinces or "traps", the Emeishan Traps are multiple layers of igneous rock laid down by large mantle plume volcanic eruptions. The Emeishan Traps eruptions were serious enough to have global ecological and paleontological impact.
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.
Pampaphoneus is an extinct genus of carnivorous dinocephalian therapsid belonging to the family Anteosauridae. It lived 268 to 265 million years ago during the Wordian age of the Guadalupian period in what is now Brazil. Pampaphoneus is known by an almost complete skull with the lower jaw still articulated, discovered on the lands of the Boqueirão Farm, near the city of São Gabriel, in the state of Rio Grande do Sul. A second specimen from the same locality was reported in 2019 and 2020 but has not yet been described. It is composed of a skull associated with postcranial remains. It is the first South American species of dinocephalian to have been described. The group was previously known in South America only by a few isolated teeth and a jaw fragment reported in 2000 in the same region of Brazil. Phylogenetic analysis conducted by Cisneros and colleagues reveals that Pampaphoneus is closely related to anteosaurs from European Russia, indicating a closer faunal relationship between South America and Eastern Europe than previously thought, thus promoting a Pangea B continental reconstruction.
The Middleton Formation is a geological formation that extends through the Northern Cape, Western Cape, and Eastern Cape provinces of South Africa. It overlies the lower Abrahamskraal Formation, and is the eastern correlate, East of 24ºE, of the Teekloof Formation. Outcrops and exposures of the Middleton Formation range from Graaff-Reinet in the Eastern Cape onwards. The Middleton Formation's type locality lies near the small hamlet, Middleton, approximately 25 km south of Cookhouse. Other exposures lie in hillsides along the Great Fish River in the Eastern Cape. The Middleton Formation forms part of the Adelaide Subgroup of the Beaufort Group, which itself forms part of the Karoo Supergroup.
Alatoconchidae is an extinct family of prehistoric bivalves that lived in the early to middle Permian period. Genera belonging to Alatoconchidae are characterized by their shell that is strongly compressed in the dorsoventral direction. Some species reached large sizes of as much as 1 metre (3.3 ft) long. It is hypothesized that some species in this family got energy from chemosynthetic bacteria.
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