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216-508: Inostrancevia is an extinct genus of large carnivorous therapsids which lived during the Late Permian in what is now European Russia and Southern Africa . The first-known fossils of this gorgonopsian were discovered in the context of a long series of excavations carried out from 1899 to 1914 in the Northern Dvina , Russia. Among these are two near-complete skeletons embodying

432-508: A dicynodont , while the attributed canine tooth is indistinguishable from that of Inostrancevia . Since then, Leogorgon has been recognized as a nomen dubium of which part of the fossils possibly come from Inostrancevia . Other species belonging to distinct lineages were sometimes inadvertently classified in the genus Inostrancevia . For example, in 1940, Efremov classifies a gorgonopsian of then-problematic status as I. progressus . However, in 1955, Alexey Bystrow moved this species to

648-438: A food chain who lose their prey. "Species coextinction is a manifestation of one of the interconnectednesses of organisms in complex ecosystems ... While coextinction may not be the most important cause of species extinctions, it is certainly an insidious one." Coextinction is especially common when a keystone species goes extinct. Models suggest that coextinction is the most common form of biodiversity loss . There may be

864-657: A nautilus to the Royal Society that was more than two feet in diameter, and morphologically distinct from any known living species. Hooke theorized that this was simply because the species lived in the deep ocean and no one had discovered them yet. While he contended that it was possible a species could be "lost", he thought this highly unlikely. Similarly, in 1695, Sir Thomas Molyneux published an account of enormous antlers found in Ireland that did not belong to any extant taxa in that area. Molyneux reasoned that they came from

1080-415: A species or a population is the variety of genetic information in its living members. A large gene pool (extensive genetic diversity ) is associated with robust populations that can survive bouts of intense selection . Meanwhile, low genetic diversity (see inbreeding and population bottlenecks ) reduces the range of adaptions possible. Replacing native with alien genes narrows genetic diversity within

1296-436: A viable population for species preservation and possible future reintroduction to the wild, through use of carefully planned breeding programs . The extinction of one species' wild population can have knock-on effects, causing further extinctions. These are also called "chains of extinction". This is especially common with extinction of keystone species . A 2018 study indicated that the sixth mass extinction started in

1512-551: A "scaled-up version" of Lycaenops . The numerous descriptions given to this taxon make it one of the most emblematic animals of the Permian period, mainly because of its large size among gorgonopsians, rivaled only by the South African genus Rubidgea , the latter having a roughly similar size. Gorgonopsians were skeletally robust, yet long-limbed for therapsids, with a somewhat dog -like stance, though with outwards-turned elbows. It

1728-474: A Lazarus species when extant individuals were described in 2019. Attenborough's long-beaked echidna ( Zaglossus attenboroughi ) is an example of a Lazarus species from Papua New Guinea that had last been sighted in 1962 and believed to be possibly extinct, until it was recorded again in November 2023. Some species currently thought to be extinct have had continued speculation that they may still exist, and in

1944-407: A book, which are the first in-depth descriptions of the fossils today attributed to this taxon. In his works, Pravoslavlev changed the typography of the name " Inostranzevia " to " Inostrancevia ". Although the original name has been used a few times in recent scientific literature , the second term has since entered into universal usage and must be maintained according to the rule of article 33.3.1 of

2160-495: A cascade of coextinction across the trophic levels . Such effects are most severe in mutualistic and parasitic relationships. An example of coextinction is the Haast's eagle and the moa : the Haast's eagle was a predator that became extinct because its food source became extinct. The moa were several species of flightless birds that were a food source for the Haast's eagle. Extinction as

2376-813: A century after its original naming, with the United States Geological Survey until 1941 considering the Permian a subsystem of the Carboniferous equivalent to the Mississippian and Pennsylvanian . The Permian Period is divided into three epochs , from oldest to youngest, the Cisuralian, Guadalupian, and Lopingian. Geologists divide the rocks of the Permian into a stratigraphic set of smaller units called stages , each formed during corresponding time intervals called ages. Stages can be defined globally or regionally. For global stratigraphic correlation,

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2592-612: A city in Perm Krai. The stage was introduced by Alexandr Antonovich Stukenberg in 1890. The Kungurian currently lacks a defined GSSP. Recent proposals have suggested the appearance of Neostreptognathodus pnevi as the lower boundary. The Guadalupian Series is named after the Guadalupe Mountains in Texas and New Mexico, where extensive marine sequences of this age are exposed. It was named by George Herbert Girty in 1902. The Roadian

2808-413: A clearly visible chin -like structure. The four recognized species are distinguished by their own specific characteristics. I. alexandri is distinguished by its relatively narrow occiput , a broad and rounded oval temporal fenestra and the transverse flangues of the pterygoid with teeth. I. latifrons is distinguished by a comparatively lower and broader snout, larger parietal region, fewer teeth and

3024-404: A closely related taxon. Also in his article, he considers that I. proclivis is a junior synonym of I. alexandri , but remains open to the question of the existence of this species, arguing his opinion with the insufficient preservation of type specimens. This taxon will be definitively judged as being conspecific to I. alexandri in the revision of the genus carried out by Tatarinov in 1974. In

3240-622: A coal swamp community, has an upper canopy consisting of lycopsid tree Sigillaria , with a lower canopy consisting of Marattialean tree ferns, and Noeggerathiales. Early conifers appeared in the Late Carboniferous, represented by primitive walchian conifers, but were replaced with more derived voltzialeans during the Permian. Permian conifers were very similar morphologically to their modern counterparts, and were adapted to stressed dry or seasonally dry climatic conditions. The increasing aridity, especially at low latitudes, facilitated

3456-429: A common ancestor with modern horses. Pseudoextinction is much easier to demonstrate for larger taxonomic groups. A Lazarus taxon or Lazarus species refers to instances where a species or taxon was thought to be extinct, but was later rediscovered. It can also refer to instances where large gaps in the fossil record of a taxon result in fossils reappearing much later, although the taxon may have ultimately become extinct at

3672-423: A double articulation with the skull—unlike in mammals where the rear joint articular bone has become the malleus ear bone. Antón envisioned gorgonopsians would hunt by leaving their cover when prey was close enough, and use their relatively greater speed to pounce quickly on it, grab it with their forelimbs, and bite any part of the body that would fit in their jaws. Such a bite would cause a large loss of blood, but

3888-527: A dramatic increase in diversification during the Early Permian. Towards the end of the Permian, there was a substantial drop in both origination and extinction rates. The dominant insects during the Permian Period were early representatives of Paleoptera , Polyneoptera , and Paraneoptera . Palaeodictyopteroidea , which had represented the dominant group of insects during the Carboniferous, declined during

4104-399: A fact that was accepted by most scientists. The primary debate focused on whether this turnover caused by extinction was gradual or abrupt in nature. Cuvier understood extinction to be the result of cataclysmic events that wipe out huge numbers of species, as opposed to the gradual decline of a species over time. His catastrophic view of the nature of extinction garnered him many opponents in

4320-451: A feature associated with an advanced sense of smell, which would have helped them track prey and carrion . The canine saber teeth were used for delivering the slashing killing-bite, while the incisors, which formed an arch in front of the saber teeth, held the prey and cut the flesh while feeding. To allow them to increase their gape when biting, gorgonopsians had several bones in their mandibles that could move in relation to each other and had

4536-453: A group of carnivorous stem mammals with saber teeth that disappeared at the end of the Permian . The first classifications placed Inostrancevia as close to African taxa before 1948, the year in which Friedrich von Huene erected a distinct family, Inostranceviidae. Although this model was mainly followed in the scientific literature of the 20th and early 21st centuries, phylogenetic analysis published since 2018 consider it to belong to

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4752-507: A group of derived Russian origin gorgonopsians, now classified alongside the genera Suchogorgon , Sauroctonus and Pravoslavlevia , the latter and Inostrancevia forming the subfamily Inostranceviinae . Russian and African fossil records show that Inostrancevia lived in river ecosystems containing many tetrapods , where it appears to have been the main predator . These faunas were mainly occupied by dicynodonts and pareiasaurs , which would most likely have constituted its prey. In

4968-708: A higher risk of extinction and die out faster than less sexually dimorphic species, the least sexually dimorphic species surviving for millions of years while the most sexually dimorphic species die out within mere thousands of years. Earlier studies based on counting the number of currently living species in modern taxa have shown a higher number of species in more sexually dimorphic taxa which have been interpreted as higher survival in taxa with more sexual selection, but such studies of modern species only measure indirect effects of extinction and are subject to error sources such as dying and doomed taxa speciating more due to splitting of habitat ranges into more small isolated groups during

5184-405: A large range, a lack of individuals of both sexes (in sexually reproducing species), or other reasons. Pinpointing the extinction (or pseudoextinction ) of a species requires a clear definition of that species . If it is to be declared extinct, the species in question must be uniquely distinguishable from any ancestor or daughter species, and from any other closely related species. Extinction of

5400-592: A later point. The coelacanth , a fish related to lungfish and tetrapods , is an example of a Lazarus taxon that was known only from the fossil record and was considered to have been extinct since the end of the Cretaceous Period . In 1938, however, a living specimen was found off the Chalumna River (now Tyolomnqa) on the east coast of South Africa. Calliostoma bullatum , a species of deepwater sea snail originally described from fossils in 1844 proved to be

5616-469: A less developed palatal tuberosities. I. uralensis is characterized by a transversely elongated oval slot-like temporal fenestra. I. africana is characterized by the strong constriction of the jugal under the orbit, a proportionally longer snout, the pineal foramen located in a deep parietal depression, as well as a much more raised and massive dentary bone. The jaws of Inostrancevia are powerfully developed, equipped with teeth able to hold and tear

5832-509: A major group of carnivorous therapsids whose oldest-known representatives come from South Africa and appear in the fossil record from the Middle Permian . During this period, the majority of representatives of this clade were quite small and their ecosystems were mainly dominated by dinocephalians , large therapsids characterized by strong bone robustness. However, some genera, notably Phorcys , are relatively larger in size and already occupy

6048-587: A mathematical model that falls in all positions. By contrast, conservation biology uses the extinction vortex model to classify extinctions by cause. When concerns about human extinction have been raised, for example in Sir Martin Rees ' 2003 book Our Final Hour , those concerns lie with the effects of climate change or technological disaster. Human-driven extinction started as humans migrated out of Africa more than 60,000 years ago. Currently, environmental groups and some governments are concerned with

6264-456: A natural part of the evolutionary process. Only recently have extinctions been recorded and scientists have become alarmed at the current high rate of extinctions . Most species that become extinct are never scientifically documented. Some scientists estimate that up to half of presently existing plant and animal species may become extinct by 2100. A 2018 report indicated that the phylogenetic diversity of 300 mammalian species erased during

6480-520: A new genus of Russian gorgonopsian under the name of Leogorgon klimovensis , on the basis of a partial braincase and a large referred canine , both discovered in the Klimovo-1 locality, in the Vologda Oblast . In his official description, Ivakhnenko classifies this taxon among the subfamily Rubidgeinae , whose fossils are exclusively known from what is now Africa. This would therefore make Leogorgon

6696-441: A new mega-predator or by transporting animals and plants from one part of the world to another. Such introductions have been occurring for thousands of years, sometimes intentionally (e.g. livestock released by sailors on islands as a future source of food) and sometimes accidentally (e.g. rats escaping from boats). In most cases, the introductions are unsuccessful, but when an invasive alien species does become established,

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6912-426: A partial skeleton of a large gorgonopsian which include an almost complete skull, cataloged as NMQR 4000. During a second expedition launched the following year, John Nyaphuli discovers another partial skeleton similar to that of the previously discovered specimen, cataloged as NMQR 3707. The existence of these two specimens are mentioned in 2014 in the chapter of a work listing the discoveries made at this farm, but it

7128-421: A particularly large jaw opening angle, which would have allowed it to inflict fatal bites . Gorgonopsians in general would have been relatively fast predators, killing their prey by delivering slashing bites with their saber teeth . The skeleton is robustly constructed, but new studies are necessary for a better anatomical description and understanding about its paleobiological functioning. Gorgonopsians were

7344-472: A peak of diversity in the Cisuralian, with a substantial decline during the Guadalupian-Lopingian following Olson's extinction, with the family diversity dropping below Carboniferous levels. Embolomeres , a group of aquatic crocodile-like limbed vertebrates that are reptilliomorphs under some phylogenies. They previously had their last records in the Cisuralian, are now known to have persisted into

7560-610: A population a higher chance in the short term of surviving an adverse change in conditions. Effects that cause or reward a loss in genetic diversity can increase the chances of extinction of a species. Population bottlenecks can dramatically reduce genetic diversity by severely limiting the number of reproducing individuals and make inbreeding more frequent. Extinction sometimes results for species evolved to specific ecologies that are subjected to genetic pollution —i.e., uncontrolled hybridization , introgression and genetic swamping that lead to homogenization or out-competition from

7776-514: A protective cover, over plants such as ferns that disperse spores in a wetter environment. The first modern trees ( conifers , ginkgos and cycads ) appeared in the Permian. Three general areas are especially noted for their extensive Permian deposits—the Ural Mountains (where Perm itself is located), China, and the southwest of North America, including the Texas red beds. The Permian Basin in

7992-407: A race of animals to become extinct. A series of fossils were discovered in the late 17th century that appeared unlike any living species. As a result, the scientific community embarked on a voyage of creative rationalization, seeking to understand what had happened to these species within a framework that did not account for total extinction. In October 1686, Robert Hooke presented an impression of

8208-502: A reduction in agricultural productivity. Furthermore, increased erosion contributes to poorer water quality by elevating the levels of sediment and pollutants in rivers and streams. Habitat degradation through toxicity can kill off a species very rapidly, by killing all living members through contamination or sterilizing them. It can also occur over longer periods at lower toxicity levels by affecting life span, reproductive capacity, or competitiveness. Habitat degradation can also take

8424-486: A result of climate change has been confirmed by fossil studies. Particularly, the extinction of amphibians during the Carboniferous Rainforest Collapse , 305 million years ago. A 2003 review across 14 biodiversity research centers predicted that, because of climate change, 15–37% of land species would be "committed to extinction" by 2050. The ecologically rich areas that would potentially suffer

8640-441: A smaller representative. In Tanzania, however, the taxon was coeval with a considerable number of other gorgonopsians, including even the large rubidgeines Dinogorgon and Rubidgea . In South Africa, Inostrancevia would probably have occupied the place of the main apexpredator after the extinction of the rubidgeines . However, it is possible that I. africana would not have been the only gorgonopsian to have been discovered on

8856-479: A species (or replacement by a daughter species) plays a key role in the punctuated equilibrium hypothesis of Stephen Jay Gould and Niles Eldredge . In ecology , extinction is sometimes used informally to refer to local extinction , in which a species ceases to exist in the chosen area of study, despite still existing elsewhere. Local extinctions may be made good by the reintroduction of individuals of that species taken from other locations; wolf reintroduction

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9072-439: A species may come suddenly when an otherwise healthy species is wiped out completely, as when toxic pollution renders its entire habitat unliveable; or may occur gradually over thousands or millions of years, such as when a species gradually loses out in competition for food to better adapted competitors. Extinction may occur a long time after the events that set it in motion, a phenomenon known as extinction debt . Assessing

9288-404: A species or group of species. "Just as each species is unique", write Beverly and Stephen C. Stearns , "so is each extinction ... the causes for each are varied—some subtle and complex, others obvious and simple". Most simply, any species that cannot survive and reproduce in its environment and cannot move to a new environment where it can do so, dies out and becomes extinct. Extinction of

9504-451: A species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively. This difficulty leads to phenomena such as Lazarus taxa , where a species presumed extinct abruptly "reappears" (typically in the fossil record ) after a period of apparent absence. More than 99% of all species that ever lived on Earth , amounting to over five billion species, are estimated to have died out. It

9720-518: A subsequent report, IPBES listed unsustainable fishing, hunting and logging as being some of the primary drivers of the global extinction crisis. In June 2019, one million species of plants and animals were at risk of extinction. At least 571 plant species have been lost since 1750, but likely many more. The main cause of the extinctions is the destruction of natural habitats by human activities, such as cutting down forests and converting land into fields for farming. A dagger symbol (†) placed next to

9936-477: A thesis written in 2007, German paleontologist Eva V. I. Gebauer carried out the very first phylogenetic analysis of gorgonopsians. Based on observations made on the occipital bones and canines, Gebauer moved Inostrancevia as a sister taxon to the Rubidgeinae , a lineage consisting of robust African gorgonopsians. In 2016 Christian F. Kammerer regarded Gebauer's analysis as "unsatisfactory", citing that many of

10152-487: A transcontinental distribution, being present in both territories from which the group's fossils are unanimously recorded, namely in Southern Africa and European Russia. In all the geological formations concerned, Inostrancevia would have been one if not the main apexpredator of these faunas, targeting a large majority of the tetrapods living alongside it, and more probably towards dicynodonts and pareiasaurs During

10368-527: A well-drained floodplain . The Usili Formation in Tanzania corresponds to an alluvial plain which would have had numerous small meandering streams passing through well-vegetated floodplains. The basement of this formation would also have housed a generally high phreatic zone . In the Russian fossil record, Inostrancevia is currently the only large gorgonopsian to have been documented, with Pravoslavlevia being

10584-630: Is a global hiatus in the terrestrial fossil record during the late Kungurian and early Roadian , referred to as "Olson's Gap" that obscures the nature of the transition. Other proposals have suggested that the North American and Russian records overlap, with the latest terrestrial North American deposition occurring during the Roadian, suggesting that there was an extinction event, dubbed " Olson's Extinction ". The Middle Permian faunas of South Africa and Russia are dominated by therapsids, most abundantly by

10800-517: Is also evidence to suggest that this event was preceded by another mass extinction, known as Olson's Extinction . The Cretaceous–Paleogene extinction event (K–Pg) occurred 66 million years ago, at the end of the Cretaceous period; it is best known for having wiped out non-avian dinosaurs , among many other species. According to a 1998 survey of 400 biologists conducted by New York 's American Museum of Natural History , nearly 70% believed that

11016-444: Is an example of this. Species that are not globally extinct are termed extant . Those species that are extant, yet are threatened with extinction, are referred to as threatened or endangered species . Currently, an important aspect of extinction is human attempts to preserve critically endangered species. These are reflected by the creation of the conservation status "extinct in the wild" (EW) . Species listed under this status by

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11232-402: Is capable of producing a bite force of 715 newtons ; although lacking the necessary jaw strength to crush bone, the analysis found that even the most massive gorgonopsians possessed a more powerful bite than other saber-toothed predators. The study also indicated that the jaw of Inostrancevia was capable of a massive gape, perhaps enabling it to deliver a lethal bite, and in a fashion similar to

11448-637: Is defined by the first appearance of the conodont Jinogondolella aserrata. The Capitanian is named after the Capitan Reef in the Guadalupe Mountains of Texas, named by George Burr Richardson in 1904, and first used in a chronostratigraphic sense by Glenister and Furnish in 1961 as a substage of the Guadalupian Stage. The Capitanian was ratified as an international stage by the ICS in 2001. The GSSP for

11664-585: Is difficult to demonstrate unless one has a strong chain of evidence linking a living species to members of a pre-existing species. For example, it is sometimes claimed that the extinct Hyracotherium , which was an early horse that shares a common ancestor with the modern horse , is pseudoextinct, rather than extinct, because there are several extant species of Equus , including zebra and donkey ; however, as fossil species typically leave no genetic material behind, one cannot say whether Hyracotherium evolved into more modern horse species or merely evolved from

11880-417: Is estimated as 100 to 1,000 times "background" rates (the average extinction rates in the evolutionary time scale of planet Earth), faster than at any other time in human history, while future rates are likely 10,000 times higher. However, some groups are going extinct much faster. Biologists Paul R. Ehrlich and Stuart Pimm , among others, contend that human population growth and overconsumption are

12096-417: Is estimated that there are currently around 8.7 million species of eukaryotes globally, and possibly many times more if microorganisms , such as bacteria , are included. Notable extinct animal species include non-avian dinosaurs , saber-toothed cats , dodos , mammoths , ground sloths , thylacines , trilobites , golden toads , and passenger pigeons . Through evolution , species arise through

12312-471: Is estimated to have a more imposing size, the skull being 60 cm (24 in) long, indicating that it would have measured 3.5 m (11 ft) and weighed 300 kg (660 lb). The size of I. uralensis is unknown due to very incomplete fossils, but it appears to be smaller than I. latifrons . The two known specimens of I. africana are among the largest gorgonopsians to have been discovered in Africa,

12528-683: Is of very robust constitution, mainly at the level of the limbs . The ungual phalanges have an acute triangular shape. Inostrancevia has the most autapomorphic postcranial skeleton identified on a gorgonopsian. The scapula of this latter is unmistakable, with an enlarged plate-like blade unlike that of any other known gorgonopsians, but its anatomy is also unusual, with ridges and thickened tibiae , especially at their joint margins. The scapular blade of Inostrancevia being extremely enlarged, its morphology will most likely be subject to future study regarding its paleobiological function. From its original description published in 1922, Inostrancevia

12744-638: Is only a brief introduction to the anatomy of the new fossil material, being the subject for future study. Earlier, in June 2007, a team of paleontologists discovered an isolated left premaxilla , cataloged as NMT RB380, in the Ruhuhu Basin, southern Tanzania . The fossil bone was subsequently scanned and identified as Inostrancevia sp. in a 2024 study led by Anna J. Brant and Christian A. Sidor . In his two works published in 1927, Pravoslavlev also named several additional gorgonopsian taxa,. In their broad revision of

12960-472: Is supported by notable cranial traits, such as the close contact between pterygoid and vomer . The discovery of other Russian gorgonopsians and the relationship between them and Inostrancevia has never before been recognized for the simple reason that some authors undoubtedly compared them to African genera. The classification proposed by Kammerer and Masyutin will serve as the basis for all other subsequent phylogenetic studies of gorgonopsians. Using this model,

13176-592: Is the destruction of ocean floors by bottom trawling . Diminished resources or introduction of new competitor species also often accompany habitat degradation. Global warming has allowed some species to expand their range, bringing competition to other species that previously occupied that area. Sometimes these new competitors are predators and directly affect prey species, while at other times they may merely outcompete vulnerable species for limited resources. Vital resources including water and food can also be limited during habitat degradation, leading to extinction. In

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13392-408: Is the largest known gorgonopsian, being rivaled in size only by the imposing Rubidgea . It has a broad and elongated skull equipped with large oval-shaped temporal fenestrae . It also has very advanced dentition, possessing large canines , the longest of which can reach 15 cm (5.9 in) and which may have been used to shear the skin of prey. Like most other gorgonopsians, Inostrancevia had

13608-525: Is the most important determinant of genus extinction at background rates but becomes increasingly irrelevant as mass extinction arises. Limited geographic range is a cause both of small population size and of greater vulnerability to local environmental catastrophes. Extinction rates can be affected not just by population size, but by any factor that affects evolvability , including balancing selection , cryptic genetic variation , phenotypic plasticity , and robustness . A diverse or deep gene pool gives

13824-452: Is thought to have existed during the Early Permian. Though the fossil record is fragmentary, lungfish appear to have undergone an evolutionary diversification and size increase in freshwater habitats during the Early Permian, but subsequently declined during the middle and late Permian. Conodonts experienced their lowest diversity of their entire evolutionary history during the Permian. Permian chondrichthyan faunas are poorly known. Members of

14040-441: Is unknown whether non- mammaliaform therapsids such as gorgonopsians were covered in hair or not. The specimens PIN 2005/1578 and PIN 1758, belonging to I. alexandri , are among the largest and most complete gorgonopsian fossils identified to date. Both specimens are around 3 m (9.8 ft) long, with the skulls alone measuring over 50 cm (20 in). However, I. latifrons , although known from more fragmentary fossils,

14256-471: The ICZN . Among the many species of Inostrancevia erected and described on its part, only I. latifrons is found to be valid . The holotype of this species, cataloged PIN 2005/1857, consists of a large skull missing the lower jaw, discovered in the same locality as that of the first known specimens of I. alexandri . Another skull was also discovered in the same locality as the holotype, while an incomplete skeleton

14472-580: The International Commission on Stratigraphy (ICS) ratify global stages based on a Global Boundary Stratotype Section and Point (GSSP) from a single formation (a stratotype ) identifying the lower boundary of the stage. The ages of the Permian, from youngest to oldest, are: For most of the 20th century, the Permian was divided into the Early and Late Permian, with the Kungurian being the last stage of

14688-474: The International Union for Conservation of Nature (IUCN) are not known to have any living specimens in the wild and are maintained only in zoos or other artificial environments. Some of these species are functionally extinct, as they are no longer part of their natural habitat and it is unlikely the species will ever be restored to the wild. When possible, modern zoological institutions try to maintain

14904-527: The Late Permian when Inostrancevia lived, the Southern Urals (close in proximity to the Sokolki assemblage) were located around latitude 28 – 34°N and defined as a " cold desert " dominated by fluvial deposits. The Salarevo Formation in particular (a horizon where the Russian species Inostrancevia hails from) was deposited in a seasonal, semi-arid -to- arid area with multiple shallow water lakes which

15120-477: The Late Pleistocene could take up to 5 to 7 million years to restore mammal diversity to what it was before the human era. Extinction of a parent species where daughter species or subspecies are still extant is called pseudoextinction or phyletic extinction. Effectively, the old taxon vanishes, transformed ( anagenesis ) into a successor, or split into more than one ( cladogenesis ). Pseudoextinction

15336-707: The North China Craton , the South China Block and Indochina fused to each other and Pangea by the end of the Permian. The Zechstein Sea , a hypersaline epicontinental sea , existed in what is now northwestern Europe. Large continental landmass interiors experience climates with extreme variations of heat and cold (" continental climate ") and monsoon conditions with highly seasonal rainfall patterns. Deserts seem to have been widespread on Pangaea. Such dry conditions favored gymnosperms , plants with seeds enclosed in

15552-675: The Paleo-Tethys Ocean , a large ocean that existed between Asia and Gondwana. The Cimmeria continent rifted away from Gondwana and drifted north to Laurasia , causing the Paleo-Tethys Ocean to shrink. A new ocean was growing on its southern end, the Neotethys Ocean , an ocean that would dominate much of the Mesozoic Era. A magmatic arc, containing Hainan on its southwesternmost end, began to form as Panthalassa subducted under

15768-591: The Sydney Basin , and palaeoclimatic models of the Earth's climate based on the behaviour of modern weather patterns showing that such a megamonsoon would occur given the continental arrangement of the Permian. The aforementioned increasing equatorial aridity was likely driven by the development and intensification of this Pangaean megamonsoon. Permian marine deposits are rich in fossil mollusks , brachiopods , and echinoderms . Brachiopods were highly diverse during

15984-447: The U.S. states of Texas and New Mexico is so named because it has one of the thickest deposits of Permian rocks in the world. Sea levels dropped slightly during the earliest Permian (Asselian). The sea level was stable at several tens of metres above present during the Early Permian, but there was a sharp drop beginning during the Roadian, culminating in the lowest sea level of the entire Palaeozoic at around present sea level during

16200-493: The Upper Permian in Northern Dvina , Arkhangelsk Oblast , northern European Russia . The locality, known as PIN 2005, consists of a creek with sandstone and lens -shaped exposures in a bank escarpment , containing many particularly well-preserved fossil skeletons. This type of fauna from this period, previously known only from South Africa and India , is considered as one of the greatest paleontological discoveries of

16416-399: The Ural Mountains in the years 1840 and 1841. Murchison identified "vast series of beds of marl , schist , limestone , sandstone and conglomerate" that succeeded Carboniferous strata in the region. Murchison, in collaboration with Russian geologists, named the period after the surrounding Russian region of Perm, which takes its name from the medieval kingdom of Permia that occupied

16632-417: The premaxilla , unlike other representatives of the group who generally have five. The postcanine teeth are present on the upper jaw, on its slightly upturned alveolar edges. In contrast, they are completely absent from the lower jaw. There are indications that the tooth replacement would have taken place by the young teeth, growing at the root of the old ones and gradually supplanting them. The capsule of

16848-563: The pseudosuchians , dinosaurs , and pterosaurs in the following Triassic, first appeared and diversified during the Late Permian, including the first appearance of the Archosauriformes during the latest Permian. Cynodonts , the group of therapsids ancestral to modern mammals , first appeared and gained a worldwide distribution during the Late Permian. Another group of therapsids, the therocephalians (such as Lycosuchus ), arose in

17064-486: The skin of prey. The teeth are also devoid of cusps and can be distinguished into three types: the incisors , the canines and the postcanines . All teeth are more or less laterally compressed and have finely serrated front and rear edges. When the mouth is closed, the upper canines move into position at the sides of the mandible , reaching its lower edge. The canines of Inostrancevia measuring between 12 cm (4.7 in) and 15 cm (5.9 in), they are among

17280-410: The slender-billed curlew ( Numenius tenuirostris ), not seen since 2007. As long as species have been evolving, species have been going extinct. It is estimated that over 99.9% of all species that ever lived are extinct. The average lifespan of a species is 1–10 million years, although this varies widely between taxa. A variety of causes can contribute directly or indirectly to the extinction of

17496-484: The strata of the Paris basin. They saw alternating saltwater and freshwater deposits, as well as patterns of the appearance and disappearance of fossils throughout the record. From these patterns, Cuvier inferred historic cycles of catastrophic flooding, extinction, and repopulation of the earth with new species. Cuvier's fossil evidence showed that very different life forms existed in the past than those that exist today,

17712-619: The 20 biodiversity goals laid out by the Aichi Biodiversity Targets in 2010, only 6 were "partially achieved" by the deadline of 2020. The report warned that biodiversity will continue to decline if the status quo is not changed, in particular the "currently unsustainable patterns of production and consumption, population growth and technological developments". In a 2021 report published in the journal Frontiers in Conservation Science , some top scientists asserted that even if

17928-714: The 2023 study by Kammerer and colleagues describing I. africana recovers it as a sister taxon to I. alexandri within the Russian origin clade. As with previous classifications, Pravoslavlevia is still considered as the sister taxon of Inostrancevia . The following cladogram shows the position of Inostrancevia within the Gorgonopsia after Kammerer and Rubidge (2022): Nochnitsa Viatkogorgon Suchogorgon Sauroctonus Pravoslavlevia Inostrancevia Phorcys Eriphostoma Gorgonops Cynariops Lycaenops Smilesaurus Arctops Arctognathus Rubidgeinae Gorgonopsians form

18144-425: The 21st century, although with some alternative classifications. In 1974, Tatarinov classified Pravoslavlevia as a sister taxon of Inostrancevia within this family. In 1989, Denise Sigogneau-Russell proposes a similar classification, but moves the taxon reuniting the two genera as a subfamily, being renamed Inostranceviinae , and is classified in the more general family Gorgonopsidae. In 2002, in his revision of

18360-451: The Aichi Biodiversity Targets set for 2020 had been achieved, it would not have resulted in a significant mitigation of biodiversity loss. They added that failure of the global community to reach these targets is hardly surprising given that biodiversity loss is "nowhere close to the top of any country's priorities, trailing far behind other concerns such as employment, healthcare, economic growth, or currency stability." For much of history,

18576-539: The Asselian, Sakmarian, and Artinskian stages. The Kungurian was later added to conform to the Russian "Lower Permian". Albert Auguste Cochon de Lapparent in 1900 had proposed the "Uralian Series", but the subsequent inconsistent usage of this term meant that it was later abandoned. The Asselian was named by the Russian stratigrapher V.E. Ruzhenchev in 1954, after the Assel River in the southern Ural Mountains. The GSSP for

18792-414: The Carboniferous. Pangaea was surrounded by the superocean Panthalassa . The Carboniferous rainforest collapse left behind vast regions of desert within the continental interior. Amniotes, which could better cope with these drier conditions, rose to dominance in place of their amphibian ancestors. Various authors recognise at least three, and possibly four extinction events in the Permian. The end of

19008-661: The Cisuralian. Another cool period began around the middle Capitanian. This cool period, lasting for 3-4 Myr, was known as the Kamura Event. It was interrupted by the Emeishan Thermal Excursion in the late part of the Capitanian, around 260 million years ago, corresponding to the eruption of the Emeishan Traps . This interval of rapid climate change was responsible for the Capitanian mass extinction event. During

19224-450: The Cisuralian. Permian synapsids included some large members such as Dimetrodon . The special adaptations of synapsids enabled them to flourish in the drier climate of the Permian and they grew to dominate the vertebrates. A faunal turnover occurred around the transition between the Cisuralian and Guadalupian, with the decline of amphibians and the replacement of pelycosaurs (a paraphyletic group) with more advanced therapsids , although

19440-490: The Early Permian Chemnitz petrified forest of Germany demonstrates that they had complex branching patterns similar to modern angiosperm trees. By the Late Permian, high thin forests had become widespread across the globe, as evidenced by the global distribution of weigeltisaurids. The oldest likely record of Ginkgoales (the group containing Ginkgo and its close relatives) is Trichopitys heteromorpha from

19656-627: The Early Permian ( Cisuralian ) saw a major faunal turnover, with most lineages of primitive " pelycosaur " synapsids becoming extinct, being replaced by more advanced therapsids . The end of the Capitanian Stage of the Permian was marked by the major Capitanian mass extinction event , associated with the eruption of the Emeishan Traps . The Permian (along with the Paleozoic) ended with the Permian–Triassic extinction event (colloquially known as

19872-591: The Early Permian. Glenister and colleagues in 1992 proposed a tripartite scheme, advocating that the Roadian-Capitanian was distinct from the rest of the Late Permian, and should be regarded as a separate epoch. The tripartite split was adopted after a formal proposal by Glenister et al. (1999). Historically, most marine biostratigraphy of the Permian was based on ammonoids ; however, ammonoid localities are rare in Permian stratigraphic sections, and species characterise relatively long periods of time. All GSSPs for

20088-561: The Early Triassic, but a Permian origin is suspected. The diversity of coelacanths is relatively low throughout the Permian in comparison to other marine fishes, though there is an increase in diversity during the terminal Permian (Changhsingian), corresponding with the highest diversity in their evolutionary history during the Early Triassic. Diversity of freshwater fish faunas was generally low and dominated by lungfish and "Paleopterygians". The last common ancestor of all living lungfish

20304-557: The Earth is currently in the early stages of a human-caused mass extinction, known as the Holocene extinction . In that survey, the same proportion of respondents agreed with the prediction that up to 20% of all living populations could become extinct within 30 years (by 2028). A 2014 special edition of Science declared there is widespread consensus on the issue of human-driven mass species extinctions. A 2020 study published in PNAS stated that

20520-629: The Great Dying), the largest mass extinction in Earth's history (which is the last of the three or four crises that occurred in the Permian), in which nearly 81% of marine species and 70% of terrestrial species died out, associated with the eruption of the Siberian Traps . It took well into the Triassic for life to recover from this catastrophe; on land, ecosystems took 30 million years to recover. Prior to

20736-476: The Late Lopingian during the Permian–Triassic extinction event , mainly due to volcanic activities that originated in the Siberian Traps . The resulting eruption caused a significant climatic disruption unfavorable to their survival, leading to their extinction. Their ecological niches gave way to modern terrestrial ecosystems including sauropsids , mostly archosaurs , and among the few therapsids surviving

20952-472: The Late Permian. Members of the modern orders Archostemata and Adephaga are known from the Late Permian. Complex wood boring traces found in the Late Permian of China suggest that members of Polyphaga , the most diverse group of modern beetles, were also present by the Late Permian. The terrestrial fossil record of the Permian is patchy and temporally discontinuous. Early Permian records are dominated by equatorial Europe and North America, while those of

21168-606: The Late Permian. By the Changhsingian, only a handful (4-6) genera remained. Corals exhibited a decline in diversity over the course of the Middle and Late Permian. Terrestrial life in the Permian included diverse plants, fungi , arthropods , and various types of tetrapods . The period saw a massive desert covering the interior of Pangaea . The warm zone spread in the northern hemisphere, where extensive dry desert appeared. The rocks formed at that time were stained red by iron oxides,

21384-614: The Lopingian in China. Modern amphibians ( lissamphibians ) are suggested to have originated during Permian, descending from a lineage of dissorophoid temnospondyls or lepospondyls . The diversity of fish during the Permian is relatively low compared to the following Triassic. The dominant group of bony fishes during the Permian were the " Paleopterygii " a paraphyletic grouping of Actinopterygii that lie outside of Neopterygii . The earliest unequivocal members of Neopterygii appear during

21600-585: The Lopingian series. The GSSP for the base of the Wuchiapingian is located at Penglaitan, Guangxi , China and was ratified in 2004. The boundary is defined by the first appearance of Clarkina postbitteri postbitteri The Changhsingian was originally derived from the Changxing Limestone, a geological unit first named by the Grabau in 1923, ultimately deriving from Changxing County , Zhejiang .The GSSP for

21816-577: The Lopingian to a series, including all Permian deposits in South China that overlie the Maokou Limestone. In 1995, a vote by the Subcommission on Permian Stratigraphy of the ICS adopted the Lopingian as an international standard chronostratigraphic unit. The Wuchiapinginan and Changhsingian were first introduced in 1962, by J. Z. Sheng as the "Wuchiaping Formation" and "Changhsing Formation" within

22032-507: The Middle Permian. There were no flying vertebrates, though the extinct lizard-like reptile family Weigeltisauridae from the Late Permian had extendable wings like modern gliding lizards , and are the oldest known gliding vertebrates. Permian stem-amniotes consisted of lepospondyli and batrachosaurs , according to some phylogenies; according to others, stem-amniotes are represented only by diadectomorphs . Temnospondyls reached

22248-594: The Middle and Late Permian are dominated by temperate Karoo Supergroup sediments of South Africa and the Ural region of European Russia. Early Permian terrestrial faunas of North America and Europe were dominated by primitive pelycosaur synapsids including the herbivorous edaphosaurids , and carnivorous sphenacodontids , diadectids and amphibians . Early Permian reptiles, such as acleistorhinids , were mostly small insectivores. Synapsids (the group that would later include mammals) thrived and diversified greatly during

22464-521: The Nooitgedacht 68 farm, because an indeterminate specimen belonging to this group is also listed there. In southern Africa, dicynodonts are the most abundant fossil tetrapods, while in the Russian archives only Vivaxosaurus is known. Apart from gorgonopsians, the genus was also contemporaneous with other theriodonts , such as therocephalians (mainly akidnognathids ) and numerous basal cynodonts such as Dvinia and Procynosuchus . Exclusively in

22680-513: The North American moose and that the animal had once been common on the British Isles . Rather than suggest that this indicated the possibility of species going extinct, he argued that although organisms could become locally extinct, they could never be entirely lost and would continue to exist in some unknown region of the globe. The antlers were later confirmed to be from the extinct deer Megaloceros . Hooke and Molyneux's line of thinking

22896-506: The Ochoan, corresponding to the Lopingian. During the Permian, all the Earth 's major landmasses were collected into a single supercontinent known as Pangaea , with the microcontinental terranes of Cathaysia to the east. Pangaea straddled the equator and extended toward the poles, with a corresponding effect on ocean currents in the single great ocean (" Panthalassa ", the "universal sea"), and

23112-518: The Paris basin, could be formed by a slow rise and fall of sea levels . The concept of extinction was integral to Charles Darwin 's On the Origin of Species , with less fit lineages disappearing over time. For Darwin, extinction was a constant side effect of competition . Because of the wide reach of On the Origin of Species , it was widely accepted that extinction occurred gradually and evenly (a concept now referred to as background extinction ). It

23328-603: The Permian are based around the first appearance datum of specific species of conodont , an enigmatic group of jawless chordates with hard tooth-like oral elements. Conodonts are used as index fossils for most of the Palaeozoic and the Triassic. The Cisuralian Series is named after the strata exposed on the western slopes of the Ural Mountains in Russia and Kazakhstan. The name was proposed by J. B. Waterhouse in 1982 to comprise

23544-582: The Permian, representing up to a third of all insects at some localities. Mecoptera (sometimes known as scorpionflies) first appeared during the Early Permian, going on to become diverse during the Late Permian. Some Permian mecopterans, like Mesopsychidae have long proboscis that suggest they may have pollinated gymnosperms. The earliest known beetles appeared at the beginning of the Permian. Early beetles such as members of Permocupedidae were likely xylophagous , feeding on decaying wood. Several lineages such as Schizophoridae expanded into aquatic habitats by

23760-532: The Permian-Triassic boundary, corresponding to the eruption of the Siberian Traps , which released more than 5 teratonnes of CO 2 , more than doubling the atmospheric carbon dioxide concentration. A -2% δ O excursion signifies the extreme magnitude of this climatic shift. This extremely rapid interval of greenhouse gas release caused the Permian-Triassic mass extinction, as well as ushering in an extreme hothouse that persisted for several million years into

23976-503: The Permian. Xenacanthiformes , another extinct group of shark-like chondrichthyans, were common in freshwater habitats, and represented the apex predators of freshwater ecosystems. Four floristic provinces in the Permian are recognised, the Angaran , Euramerican, Gondwanan, and Cathaysian realms. The Carboniferous Rainforest Collapse would result in the replacement of lycopsid -dominated forests with tree-fern dominated ones during

24192-516: The Permian. The extinct order Productida was the predominant group of Permian brachiopods, accounting for up to about half of all Permian brachiopod genera. Brachiopods also served as important ecosystem engineers in Permian reef complexes. Amongst ammonoids , Goniatitida were a major group during the Early-Mid Permian, but declined during the Late Permian. Members of the order Prolecanitida were less diverse. The Ceratitida originated from

24408-515: The Permian. This is likely due to competition by Hemiptera , due to their similar mouthparts and therefore ecology. Primitive relatives of damselflies and dragonflies ( Meganisoptera ), which include the largest flying insects of all time, also declined during the Permian. Holometabola , the largest group of modern insects, also diversified during this time. " Grylloblattidans ", an extinct group of winged insects thought to be related to modern ice crawlers , reached their apex of diversity during

24624-477: The Russian gorgonopsians, Mikhail F. Ivakhnenko re-erects the family Inostranceviidae and classifies the taxon as one of the lineages of the superfamily "Rubidgeoidea", placed alongside the Rubidgeidae and Phtinosuchidae . One year later, in 2003, he reclassifies Inostrancevia in the family Inostranceviidae, similar to Tatarinov's proposal, but the latter classifies it alone, making it a monotypic taxon . In

24840-542: The Russian territory, Inostrancevia would have been the only large gorgonopsian present, while it would have been briefly contemporary with the rubidgeines in Tanzania. When the rubidgeines disappeared from South African territory, Inostrancevia would have in turn occupied the role of apex predator before disappearing in turn during the Permian-Triassic extinction . During the 1890s, Russian paleontologist Vladimir Amalitsky discovered freshwater sediments dating from

25056-422: The South African specimens being classified within the species I. africana . The whole genus is named in honor of Alexander Inostrantsev, professor of Vladimir P. Amalitsky , the paleontologist who described the taxon . Possessing a skull measuring approximately 40 to 60 cm (16 to 24 in) long depending on the species, all for a body length reaching 3 to 3.5 m (9.8 to 11.5 ft), Inostrancevia

25272-469: The United States government, to force the removal of Native Americans , many of whom relied on the bison for food. Upper Permian The Permian witnessed the diversification of the two groups of amniotes , the synapsids and the sauropsids ( reptiles ). The world at the time was dominated by the supercontinent Pangaea , which had formed due to the collision of Euramerica and Gondwana during

25488-967: The Usili Formation, Inostrancevia would have been contemporary with biarmosuchians of the genera Burnetia and Pembacephalus . A number of other non- synapsid tetrapods were contemporaneous with Inostrancevia . Among sauropsids , pareiasaurs, notably Scutosaurus , are the tetrapods most present in the Russian fossil record, although other representatives such as Anthodon and Pareiasaurus are known in African formations. Contemporary archosauromorphs such as Aenigmastropheus and Proterosuchus have only been identified in Africa, respectively in Tanzania and South Africa. Contemporary temnospondyls include Dvinosaurus in Russia and Peltobatrachus in Tanzania. Reptiliomorphs like Chroniosuchus and Kotlassia have been identified in Russia. Gorgonopsians, including Inostrancevia , disappeared in

25704-636: The Usolka section in the southern Urals, which was ratified in 2018. The GSSP is defined by the first appearance of Sweetognathus binodosus . The Artinskian was named after the city of Arti in Sverdlovsk Oblast , Russia. It was named by Karpinsky in 1874. The Artinskian currently lacks a defined GSSP. The proposed definition for the base of the Artinskian is the first appearance of Sweetognathus aff. S. whitei. The Kungurian takes its name after Kungur ,

25920-697: The Word Formation by Johan August Udden in 1916, Glenister and Furnish in 1961 was the first publication to use it as a chronostratigraphic term as a substage of the Guadalupian Stage. The GSSP for the base of the Wordian is located in Guadalupe Pass, Texas, within the sediments of the Getaway Limestone Member of the Cherry Canyon Formation , which was ratified in 2001. The base of the Wordian

26136-469: The Wuchiapingian, followed by a slight rise during the Changhsingian. The Permian was cool in comparison to most other geologic time periods, with modest pole to Equator temperature gradients. At the start of the Permian, the Earth was still in the Late Paleozoic icehouse (LPIA), which began in the latest Devonian and spanned the entire Carboniferous period, with its most intense phase occurring during

26352-429: The accumulation of slightly deleterious mutations , then a population will go extinct. Smaller populations have fewer beneficial mutations entering the population each generation, slowing adaptation. It is also easier for slightly deleterious mutations to fix in small populations; the resulting positive feedback loop between small population size and low fitness can cause mutational meltdown . Limited geographic range

26568-506: The amount of lava estimated to have been produced during this period, the worst-case scenario is the release of enough carbon dioxide from the eruptions to raise world temperatures five degrees Celsius. Another hypothesis involves ocean venting of hydrogen sulfide gas. Portions of the deep ocean will periodically lose all of its dissolved oxygen allowing bacteria that live without oxygen to flourish and produce hydrogen sulfide gas. If enough hydrogen sulfide accumulates in an anoxic zone ,

26784-464: The ancestors of many present-day families. Rich forests were present in many areas, with a diverse mix of plant groups. The southern continent saw extensive seed fern forests of the Glossopteris flora. Oxygen levels were probably high there. The ginkgos and cycads also appeared during this period. Insects, which had first appeared and become abundant during the preceding Carboniferous, experienced

27000-399: The authors mention that it is difficult to know if the specimen would have been similar in size to those of recognized species. The overall shape of the skull of Inostrancevia is similar to those of other gorgonopsians, i. e. long and narrow. It has a broad back skull, a raised and elongated snout , relatively small eye sockets and thin cranial arches. The pineal foramen is located near

27216-571: The base of the Asselian is located in the Aidaralash River valley near Aqtöbe , Kazakhstan, which was ratified in 1996. The beginning of the stage is defined by the first appearance of Streptognathodus postfusus . The Sakmarian is named in reference to the Sakmara River in the southern Urals, and was coined by Alexander Karpinsky in 1874. The GSSP for the base of the Sakmarian is located at

27432-418: The base of the Capitanian is located at Nipple Hill in the southeast Guadalupe Mountains of Texas, and was ratified in 2001, the beginning of the stage is defined by the first appearance of Jinogondolella postserrata. The Lopingian was first introduced by Amadeus William Grabau in 1923 as the "Loping Series" after Leping , Jiangxi , China. Originally used as a lithostraphic unit, T.K. Huang in 1932 raised

27648-454: The base of the Changhsingian is located 88 cm above the base of the Changxing Limestone in the Meishan D section, Zhejiang, China and was ratified in 2005, the boundary is defined by the first appearance of Clarkina wangi. The GSSP for the base of the Triassic is located at the base of Bed 27c at the Meishan D section, and was ratified in 2001. The GSSP is defined by the first appearance of

27864-410: The belly is carried above the ground, with the feet pointing forwards, and the limbs carried under the trunk instead of to the sides. The forelimbs had a more horizontal posture than the hindlimbs, with the elbows pointing outwards during movement, but the gait of the hindlimbs would have resembled that of mammals. As in reptiles, the tail muscles (such as the caudofemoralis ) were important in flexion of

28080-414: The canines is very large, containing up to three capsules of replacement canines at different stages of development. Although the postcranial anatomy of Inostrancevia was first described in detail in 1927 by Pravoslavlev, new discoveries and anatomical descriptions of this taxon have led authors suggesting further revisions to broaden the skeletal understanding of the animal. The skeleton of Inostrancevia

28296-466: The characters used by her analysis were based upon skull proportions that are variable within taxa, both individually and ontogenetically (i.e. traits that change through growth). In 2018, in their description of Nochnitsa and re-description of the skull of Viatkogorgon , Kammerer and Vladimir Masyutin propose that all Russian and African taxa should be separately grouped into two distinct clades. For Russian genera (except basal taxa), this relationship

28512-493: The chondrichthyan clade Holocephali , which contains living chimaeras , reached their apex of diversity during the Carboniferous-Permian, the most famous Permian representative being the "buzz-saw shark" Helicoprion , known for its unusual spiral shaped spiral tooth whorl in the lower jaw. Hybodonts , a group of shark-like chondrichthyans, were widespread and abundant members of marine and freshwater faunas throughout

28728-493: The classification of therapsids published in 1956, David Watson and Alfred Romer recognized without argumentation almost all of the taxa erected by Pravoslavlev as valid, but their opinions were never followed in subsequent works. In addition of I. latifrons , Pravoslavlev names and describes two additional species of the genus Inostrancevia : I. parva and I. proclivis . In 1940, the paleontologist Ivan Yefremov expressed doubts about this classification, and considered that

28944-616: The climate became notably more arid at the end of the Carboniferous and beginning of the Permian. Nonetheless, temperatures continued to cool during most of the Asselian and Sakmarian, during which the LPIA peaked. By 287 million years ago, temperatures warmed and the South Pole ice cap retreated in what was known as the Artinskian Warming Event (AWE), though glaciers remained present in the uplands of eastern Australia, and perhaps also

29160-661: The conodont Hindeodus parvus . The Russian Tatarian Stage includes the Lopingian, Capitanian and part of the Wordian, while the underlying Kazanian includes the rest of the Wordian as well as the Roadian. In North America, the Permian is divided into the Wolfcampian (which includes the Nealian and the Lenoxian stages); the Leonardian (Hessian and Cathedralian stages); the Guadalupian; and

29376-600: The consequences can be catastrophic. Invasive alien species can affect native species directly by eating them, competing with them, and introducing pathogens or parasites that sicken or kill them; or indirectly by destroying or degrading their habitat. Human populations may themselves act as invasive predators. According to the "overkill hypothesis", the swift extinction of the megafauna in areas such as Australia (40,000 years before present), North and South America (12,000 years before present), Madagascar , Hawaii (AD 300–1000), and New Zealand (AD 1300–1500), resulted from

29592-418: The contemporary extinction crisis "may be the most serious environmental threat to the persistence of civilization, because it is irreversible." Biologist E. O. Wilson estimated in 2002 that if current rates of human destruction of the biosphere continue, one-half of all plant and animal species of life on earth will be extinct in 100 years. More significantly, the current rate of global species extinctions

29808-540: The continental interior by the more advanced seed ferns and early conifers as a result of the Carboniferous rainforest collapse . At the close of the Permian, lycopod and equisete swamps reminiscent of Carboniferous flora survived only in Cathaysia , a series of equatorial islands in the Paleo-Tethys Ocean that later would become South China . The Permian saw the radiation of many important conifer groups, including

30024-616: The decline of early synapsid clades was apparently a slow event that lasted about 20 Ma, from the Sakmarian to the end of the Kungurian . Predator-prey interactions among terrestrial synapsids became more dynamic. If terrestrial deposition ended around the end of the Cisuralian in North America and began in Russia during the early Guadalupian, a continuous record of the transition is not preserved. Uncertain dating has led to suggestions that there

30240-471: The deliberate destruction of some species, such as dangerous viruses , and the total destruction of other problematic species has been suggested. Other species were deliberately driven to extinction, or nearly so, due to poaching or because they were "undesirable", or to push for other human agendas. One example was the near extinction of the American bison , which was nearly wiped out by mass hunts sanctioned by

30456-464: The diverse Dinocephalia . Dinocephalians become extinct at the end of the Middle Permian, during the Capitanian mass extinction event . Late Permian faunas are dominated by advanced therapsids such as the predatory sabertoothed gorgonopsians and herbivorous beaked dicynodonts , alongside large herbivorous pareiasaur parareptiles . The Archosauromorpha , the group of reptiles that would give rise to

30672-458: The earliest Permian of France. The oldest known fossils definitively assignable to modern cycads are known from the Late Permian. In Cathaysia, where a wet tropical frost-free climate prevailed, the Noeggerathiales , an extinct group of tree fern-like progymnosperms were a common component of the flora The earliest Permian (~ 298 million years ago) Cathyasian Wuda Tuff flora, representing

30888-556: The early Wuchiapingian, following the emplacement of the Emeishan Traps, global temperatures declined as carbon dioxide was weathered out of the atmosphere by the large igneous province's emplaced basalts. The late Wuchiapingian saw the finale of the Late Palaeozoic Ice Age, when the last Australian glaciers melted. The end of the Permian is marked by a temperature excursion, much larger than the Emeishan Thermal Excursion, at

31104-431: The end of the Permian. Nautiloids , a subclass of cephalopods, surprisingly survived this occurrence. There is evidence that magma , in the form of flood basalt , poured onto the Earth's surface in what is now called the Siberian Traps , for thousands of years, contributing to the environmental stress that led to mass extinction. The reduced coastal habitat and highly increased aridity probably also contributed. Based on

31320-403: The endangered wild water buffalo is most threatened with extinction by genetic pollution from the abundant domestic water buffalo ). Such extinctions are not always apparent from morphological (non-genetic) observations. Some degree of gene flow is a normal evolutionary process; nevertheless, hybridization (with or without introgression) threatens rare species' existence. The gene pool of

31536-575: The event of rediscovery would be considered Lazarus species. Examples include the thylacine , or Tasmanian tiger ( Thylacinus cynocephalus ), the last known example of which died in Hobart Zoo in Tasmania in 1936; the Japanese wolf ( Canis lupus hodophilax ), last sighted over 100 years ago; the American ivory-billed woodpecker ( Campephilus principalis ), with the last universally accepted sighting in 1944; and

31752-436: The event, mammals . However, some Russian gorgonopsians have already disappeared a little time before the event, having consequently abandoned some of their niches to large therocephalians. Extinction Extinction is the termination of a taxon by the death of its last member . A taxon may become functionally extinct before the death of its last member if it loses the capacity to reproduce and recover. Because

31968-443: The extinction crisis. According to the International Union for Conservation of Nature (IUCN), 784 extinctions have been recorded since the year 1500, the arbitrary date selected to define "recent" extinctions, up to the year 2004; with many more likely to have gone unnoticed. Several species have also been listed as extinct since 2004. If adaptation increasing population fitness is slower than environmental degradation plus

32184-475: The extinction of species caused by humanity, and they try to prevent further extinctions through a variety of conservation programs. Humans can cause extinction of a species through overharvesting , pollution , habitat destruction , introduction of invasive species (such as new predators and food competitors ), overhunting, and other influences. Explosive, unsustainable human population growth and increasing per capita consumption are essential drivers of

32400-565: The family Daraelitidae within Prolecanitida during the mid-Permian, and extensively diversified during the Late Permian. Only three families of trilobite are known from the Permian, Proetidae , Brachymetopidae and Phillipsiidae . Diversity, origination and extinction rates during the Early Permian were low. Trilobites underwent a diversification during the Kungurian-Wordian, the last in their evolutionary history, before declining during

32616-533: The field of zoology , and biology in general, and has also become an area of concern outside the scientific community. A number of organizations, such as the Worldwide Fund for Nature , have been created with the goal of preserving species from extinction. Governments have attempted, through enacting laws, to avoid habitat destruction, agricultural over-harvesting, and pollution . While many human-caused extinctions have been accidental, humans have also engaged in

32832-656: The first described specimens of this genus. It is also the first gorgonopsian identified in Russia. Several other fossil materials were discovered there, and the various finds led to confusion as to the exact number of valid species, before only two of them were formally recognized, namely I. alexandri and I . latifrons . A third species, I. uralensis , was erected in 1974, but the fossil remains of this taxon are very thin and could come from another genus. More recent research carried out in South Africa aand Tanzania has discovered specimens identified as belonging to this genus, with

33048-414: The first known representative of this group to have lived outside this continent. In 2008, however, Ivakhnenko noted that, due to its poorly known anatomy, Leogorgon could be a relative of the Russian Phthinosuchidae rather than the sole Russian representative of the Rubidgeinae. In 2016, Kammerer formally rejected Ivakhnenko's classifications, because the holotype braincase of Leogorgon likely came from

33264-450: The first work published earlier the same year, Pravoslavlev erected another genus of gorgonopsians, Amalitzkia , with the type species A. annae . In his larger work published subsequently, he erected a second species under the name of A. wladimiri . The genus as well as the two species are named in honor of the couple of paleontologists who carried out the work on the first known specimens of I. alexandri . In 1953, Vjuschkov discovered that

33480-435: The form of a physical destruction of niche habitats. The widespread destruction of tropical rainforests and replacement with open pastureland is widely cited as an example of this; elimination of the dense forest eliminated the infrastructure needed by many species to survive. For example, a fern that depends on dense shade for protection from direct sunlight can no longer survive without forest to shelter it. Another example

33696-429: The gas can rise into the atmosphere. Oxidizing gases in the atmosphere would destroy the toxic gas, but the hydrogen sulfide would soon consume all of the atmospheric gas available. Hydrogen sulfide levels might have increased dramatically over a few hundred years. Models of such an event indicate that the gas would destroy ozone in the upper atmosphere allowing ultraviolet radiation to kill off species that had survived

33912-461: The genus Amalitzkia is a junior synonym of Inostrancevia , renaming A. wladimiri to I. wladimiri , before the latter was itself recognized as a junior synonym of I. latifrons by later publications. For some unclear reason, Vjuschkov refers A. annae as a nomen nudum , when his description is quite viable. Just like A. wladimiri , A. annae will be synonymized with I. latifrons by Tatarinov in 1974. In 2003, Mikhail F. Ivakhnenko erected

34128-422: The geological department of the city's university . During World War II , part of the fossils from the collection were transferred to the Paleontological Institute of the Russian Academy of Sciences in Moscow . Among all the fossils Amalitsky described before his death are two remarkably complete skeletons of large gorgonopsians , now cataloged as PIN 1758 and PIN 2005/1578. After identification, he assigned

34344-580: The habitat retreat of taxa approaching extinction. Possible causes of the higher extinction risk in species with more sexual selection shown by the comprehensive fossil studies that rule out such error sources include expensive sexually selected ornaments having negative effects on the ability to survive natural selection , as well as sexual selection removing a diversity of genes that under current ecological conditions are neutral for natural selection but some of which may be important for surviving climate change. There have been at least five mass extinctions in

34560-540: The heaviest losses include the Cape Floristic Region and the Caribbean Basin . These areas might see a doubling of present carbon dioxide levels and rising temperatures that could eliminate 56,000 plant and 3,700 animal species. Climate change has also been found to be a factor in habitat loss and desertification . Studies of fossils following species from the time they evolved to their extinction show that species with high sexual dimorphism , especially characteristics in males that are used to compete for mating, are at

34776-453: The hindlimb, whereas the tails of mammals are merely for balance. Their feet were probably plantigrade (where the soles were placed flat on the ground), though they were likely more swift and agile than their prey. Their feet were more symmetrical compared to the reptilian condition, making contact with the ground more efficient, similar to running mammals. Inostrancevia is currently the only formally recognized gorgonopsian genus to have had

34992-447: The history of life on earth, and four in the last 350 million years in which many species have disappeared in a relatively short period of geological time. A massive eruptive event that released large quantities of tephra particles into the atmosphere is considered to be one likely cause of the " Permian–Triassic extinction event " about 250 million years ago, which is estimated to have killed 90% of species then existing. There

35208-415: The holotype skull measuring 44.2 cm (17.4 in), while that of the paratype reaches 48.1 cm (18.9 in). These proportions are matched only by the largest known specimens of Rubidgea . Based on comparisons with various other gorgonopsians, the Tanzanian specimen of Inostrancevia would have had a skull with an estimated length of between 38.5 to 69 cm (15.2 to 27.2 in) long. However,

35424-428: The holotype specimen of I. parva should be viewed as a juvenile of the genus and not as a distinct species. It was in 1953 that Boris Pavlovich Vyuschkov completely revised the species named for Inostrancevia . For I. parva , he moves it to a new genus, which he names Pravoslavlevia , in honor of the original author who named the species. Although being a distinct and valid genus, Pravoslavlevia turns out to be

35640-475: The human era since the Late Pleistocene would require 5 to 7 million years to recover. According to the 2019 Global Assessment Report on Biodiversity and Ecosystem Services by IPBES , the biomass of wild mammals has fallen by 82%, natural ecosystems have lost about half their area and a million species are at risk of extinction—all largely as a result of human actions. Twenty-five percent of plant and animal species are threatened with extinction. In

35856-506: The hypothesised killing technique of Smilodon (or 'saber-toothed cat'). Antón provided an overview of gorgonopsian biology in is 2013 book, writing that despite their differences from saber-toothed mammals, many features of their skeletons indicated they were not sluggish reptiles but active predators. While their brains were relatively smaller than those of mammals, and their sideways placed eyes provided limited stereoscopic vision , they had well-developed turbinals in their nasal cavity,

36072-431: The introduced ( or hybrid ) species. Endemic populations can face such extinctions when new populations are imported or selectively bred by people, or when habitat modification brings previously isolated species into contact. Extinction is likeliest for rare species coming into contact with more abundant ones; interbreeding can swamp the rarer gene pool and create hybrids, depleting the purebred gene pool (for example,

36288-410: The introduction of the term Permian , rocks of equivalent age in Germany had been named the Rotliegend and Zechstein , and in Great Britain as the New Red Sandstone . The term Permian was introduced into geology in 1841 by Sir Roderick Impey Murchison , president of the Geological Society of London , after extensive Russian explorations undertaken with Édouard de Verneuil in the vicinity of

36504-485: The largest identified among non- mammalian therapsids , only the anomodont Tiarajudens have similarly sized canines. In his 1927 description, Pravoslavlev describes the teeth of Inostrancevia as reminding him of those of the saber-toothed cat Machairodus . In the upper and lower jaws, these canines are roughly equal in size and are slightly curved. The incisors turn out to be very robust. A unique trait among gorgonopsians, Inostrancevia only has four incisors on

36720-409: The late 19th and early 20th centuries. After the preliminary reconnaissance of the place, Amalitsky conducts systematic research with his companion Anna P. Amalitsky  [ ru ] . The first excavations began in 1899, and several of her findings where sent to Warsaw , Poland , in order to be prepared there. The exhumations of the fossils then lasted until 1914, when the research stopped due to

36936-630: The late Carboniferous in Euramerica, and result in the differentiation of the Cathaysian floras from those of Euramerica. The Gondwanan floristic region was dominated by Glossopteridales , a group of woody gymnosperm plants, for most of the Permian, extending to high southern latitudes. The ecology of the most prominent glossopterid, Glossopteris , has been compared to that of bald cypress , living in mires with waterlogged soils. The tree-like calamites , distant relatives of modern horsetails , lived in coal swamps and grew in bamboo -like vertical thickets. A mostly complete specimen of Arthropitys from

37152-422: The latter part of the Pennsylvanian epoch. A significant trend of increasing aridification can be observed over the course of the Cisuralian. Early Permian aridification was most notable in Pangaean localities at near-equatorial latitudes. Sea levels also rose notably in the Early Permian as the LPIA slowly waned. At the Carboniferous-Permian boundary, a warming event occurred. In addition to becoming warmer,

37368-440: The main drivers of the modern extinction crisis. In January 2020, the UN's Convention on Biological Diversity drafted a plan to mitigate the contemporary extinction crisis by establishing a deadline of 2030 to protect 30% of the Earth's land and oceans and reduce pollution by 50%, with the goal of allowing for the restoration of ecosystems by 2050. The 2020 United Nations ' Global Biodiversity Outlook report stated that of

37584-421: The modern understanding of extinction as the end of a species was incompatible with the prevailing worldview. Prior to the 19th century, much of Western society adhered to the belief that the world was created by God and as such was complete and perfect. This concept reached its heyday in the 1700s with the peak popularity of a theological concept called the great chain of being , in which all life on earth, from

37800-455: The most extensive extinction event recorded in paleontology : the Permian–Triassic extinction event . 90 to 95% of marine species became extinct , as well as 70% of all land organisms. It is also the only known mass extinction of insects. Recovery from the Permian–Triassic extinction event was protracted; on land, ecosystems took 30 million years to recover. Trilobites , which had thrived since Cambrian times, finally became extinct before

38016-422: The most potent greenhouse gases ) into the atmosphere to raise world temperatures an additional five degrees Celsius. The frozen methane hypothesis helps explain the increase in carbon-12 levels found midway in the Permian–Triassic boundary layer. It also helps explain why the first phase of the layer's extinctions was land-based, the second was marine-based (and starting right after the increase in C-12 levels), and

38232-414: The mountainous regions of far northern Siberia. Southern Africa also retained glaciers during the late Cisuralian in upland environments. The AWE also witnessed aridification of a particularly great magnitude. In the late Kungurian, cooling resumed, resulting in a cool glacial interval that lasted into the early Capitanian, though average temperatures were still much higher than during the beginning of

38448-490: The name of a species or other taxon normally indicates its status as extinct. Examples of species and subspecies that are extinct include: A species is extinct when the last existing member dies. Extinction therefore becomes a certainty when there are no surviving individuals that can reproduce and create a new generation. A species may become functionally extinct when only a handful of individuals survive, which cannot reproduce due to poor health, age, sparse distribution over

38664-469: The natural course of events, species become extinct for a number of reasons, including but not limited to: extinction of a necessary host, prey or pollinator, interspecific competition , inability to deal with evolving diseases and changing environmental conditions (particularly sudden changes) which can act to introduce novel predators, or to remove prey. Recently in geological time, humans have become an additional cause of extinction of some species, either as

38880-410: The newly emerging school of uniformitarianism . Jean-Baptiste Lamarck , a gradualist and colleague of Cuvier, saw the fossils of different life forms as evidence of the mutable character of species. While Lamarck did not deny the possibility of extinction, he believed that it was exceptional and rare and that most of the change in species over time was due to gradual change. Unlike Cuvier, Lamarck

39096-411: The newly erected species I. africana , the specimen NMQR 4000 being designated as the holotype of this species, while NMQR 3707 was bequeathed as a paratype . The specific name, meaning "Africa" ​​in Latin, refers to the first proven presence of its kind within that continent. However, the article officially describing this animal focuses primarily on the stratigraphic significance of the findings and

39312-522: The next geologic epoch, the Triassic. The Permian climate was also extremely seasonal and characterised by megamonsoons , which produced high aridity and extreme seasonality in Pangaea's interiors. Precipitation along the western margins of the Palaeo-Tethys Ocean was very high. Evidence for the megamonsoon includes the presence of megamonsoonal rainforests in the Qiangtang Basin of Tibet, enormous seasonal variation in sedimentation, bioturbation, and ichnofossil deposition recorded in sedimentary facies in

39528-399: The original population, thereby increasing the chance of extinction. Habitat degradation is currently the main anthropogenic cause of species extinctions. The main cause of habitat degradation worldwide is agriculture, with urban sprawl , logging, mining, and some fishing practices close behind. The degradation of a species' habitat may alter the fitness landscape to such an extent that

39744-409: The posterior edge of the parietals and rests on a strong projection in the middle of an elongated hollow like impression. The sagittal suture is reinforced with complex curvatures. The ventral surface of the palatine bones is completely smooth, lacking traces of palatine teeth or tubercles . Just like Viatkogorgon , the top margin of the quadrate is thickened. The dentary bone appear to have

39960-403: The predator would continue to try to bite vulnerable parts of the body. Antón stated in 2013 that while the post-cranial skeletons of gorgonopsians were basically reptilian, their stance was far more upright than in more primitive synapsids, like pelycosaurs , which were more sprawling. Regular locomotion of gorgonopsians would have been similar to the "high walks" seen in crocodilians , wherein

40176-492: The present territories of Africa and European Russia, with, however, an indeterminate specimen having been identified in the Turpan Depression , in north-west China , as well as a possible fragmentary specimen discovered in the Kundaram Formation , located in central India. After the Capitanian extinction , gorgonopsians began to occupy ecological niches abandoned by dinocephalians and large therocephalians , and adopted an increasingly imposing size, which very quickly gave them

40392-702: The process of speciation —where new varieties of organisms arise and thrive when they are able to find and exploit an ecological niche —and species become extinct when they are no longer able to survive in changing conditions or against superior competition . The relationship between animals and their ecological niches has been firmly established. A typical species becomes extinct within 10 million years of its first appearance, although some species, called living fossils , survive with little to no morphological change for hundreds of millions of years. Mass extinctions are relatively rare events; however, isolated extinctions of species and clades are quite common, and are

40608-410: The relative importance of genetic factors compared to environmental ones as the causes of extinction has been compared to the debate on nature and nurture . The question of whether more extinctions in the fossil record have been caused by evolution or by competition or by predation or by disease or by catastrophe is a subject of discussion; Mark Newman, the author of Modeling Extinction , argues for

40824-439: The result of intense heating by the sun of a surface devoid of vegetation cover. A number of older types of plants and animals died out or became marginal elements. The Permian began with the Carboniferous flora still flourishing. About the middle of the Permian a major transition in vegetation began. The swamp -loving lycopod trees of the Carboniferous, such as Lepidodendron and Sigillaria , were progressively replaced in

41040-418: The role of superpredator in the one of the oldest geological strata of the Karoo Supergroup . Gorgonopsians were the first group of predatory animals to develop saber teeth , long before true mammals and dinosaurs evolved. This feature later evolved independently multiple times in different predatory mammal groups, such as felids and thylacosmilids . Geographically, gorgonopsians are mainly distributed in

41256-401: The role of superpredators. In Africa, it is mainly the rubidgeines who occupy this role, while in Russia, only Inostrancevia acquires as such, the only known gorgonopsian and contemporary of this latter, Pravoslalevia , being considerably smaller. One of the most recognizable characteristics of Inostrancevia (and other gorgonopsians, as well) is the presence of long, saber-like canines on

41472-401: The same area hundreds of years prior, and which is now located in the Perm Krai administrative region. Between 1853 and 1867, Jules Marcou recognised Permian strata in a large area of North America from the Mississippi River to the Colorado River and proposed the name Dyassic , from Dyas and Trias , though Murchison rejected this in 1871. The Permian system was controversial for over

41688-415: The separate genus Sauroctonus . A large maxilla discovered in Vladimir Oblast in the 1950s was also assigned to Inostrancevia , but the fossil would be reassigned to a large therocephalian in 1997, and later designated as the holotype of the genus Megawhaitsia in 2008. Inostrancevia is a gorgonopsian with a fairly robust morphology, the Spanish paleoartist Mauricio Antón describing it as

41904-408: The southeastern South China. The Central Pangean Mountains , which began forming due to the collision of Laurasia and Gondwana during the Carboniferous, reached their maximum height during the early Permian around 295 million years ago, comparable to the present Himalayas , but became heavily eroded as the Permian progressed. The Kazakhstania block collided with Baltica during the Cisuralian, while

42120-460: The species is no longer able to survive and becomes extinct. This may occur by direct effects, such as the environment becoming toxic , or indirectly, by limiting a species' ability to compete effectively for diminished resources or against new competitor species. Habitat destruction, particularly the removal of vegetation that stabilizes soil, enhances erosion and diminishes nutrient availability in terrestrial ecosystems. This degradation can lead to

42336-419: The spread of conifers and their increasing prevalence throughout terrestrial ecosystems. Bennettitales , which would go on to become in widespread the Mesozoic, first appeared during the Cisuralian in China. Lyginopterids , which had declined in the late Pennsylvanian and subsequently have a patchy fossil record, survived into the Late Permian in Cathaysia and equatorial east Gondwana. The Permian ended with

42552-441: The start of the World War I . When this event begins, Amalitsky tries to save his collection of fossils residing in Warsaw in order to transfer it to the Nizhny Novgorod oblast . However, the arrival of the October Revolution in 1917 and the changing politics within the country indirectly led to his death in December of the same year. Subsequently, his fossil collection was transferred to Leningrad and became an integral part of

42768-430: The sudden introduction of human beings to environments full of animals that had never seen them before and were therefore completely unadapted to their predation techniques. Coextinction refers to the loss of a species due to the extinction of another; for example, the extinction of parasitic insects following the loss of their hosts. Coextinction can also occur when a species loses its pollinator , or to predators in

42984-418: The taxon was found. However, due to its poor fossil preservation of this species, Tatarinov argues that it is possible that I. uralensis could belong to a new genus of large gorgonopsians. In 2010, the Bloemfontein Museum sent an expedition to the farm of Nooitgedacht 68, located near the town of Bethulie , in the Karoo Basin , South Africa. It was during this same expedition that Nthaopa Ntheri discovered

43200-475: The taxon, the full name of the animal is named in honor of the renowned geologist Alexander Inostrantsev  [ ru ] , who was one of Amalitsky's teachers. Amalitsky's article generally describes all the fossil discoveries made in the Northern Dvina, and not Inostrancevia itself, the article mentioning that further research on this gorgonopsian is subject to research. In 1927, one of Amalitsky's colleagues, Pavel Pravoslavlev , wrote two works, including

43416-412: The tiniest microorganism to God, is linked in a continuous chain. The extinction of a species was impossible under this model, as it would create gaps or missing links in the chain and destroy the natural order. Thomas Jefferson was a firm supporter of the great chain of being and an opponent of extinction, famously denying the extinction of the woolly mammoth on the grounds that nature never allows

43632-448: The total extinction of the dodo and the extirpation of indigenous horses to the British Isles. He similarly argued against mass extinctions , believing that any extinction must be a gradual process. Lyell also showed that Cuvier's original interpretation of the Parisian strata was incorrect. Instead of the catastrophic floods inferred by Cuvier, Lyell demonstrated that patterns of saltwater and freshwater deposits , like those seen in

43848-413: The toxic gas. There are species that can metabolize hydrogen sulfide. Another hypothesis builds on the flood basalt eruption theory. An increase in temperature of five degrees Celsius would not be enough to explain the death of 95% of life. But such warming could slowly raise ocean temperatures until frozen methane reservoirs below the ocean floor near coastlines melted, expelling enough methane (among

44064-438: The two specimens within a new genus and species , which he named Inostranzevia alexandri , the specimen PIN 2005/1578 being later recognized as its lectotype . These two specimens constitute the first known quasi-complete postcranial remains identified among gorgonopsians as well as the first representative of this group to have been identified in Russia. Although the taxon was not officially described posthumously until 1922,

44280-443: The upper and lower jaws. How these animals would have used this dentition is debated. The bite force of saber-toothed predators (like Inostrancevia ), using three-dimensional analysis, was determined by Stephan Lautenschlager and colleagues in 2020: their findings detailed that, despite morphological convergence among saber-toothed predators , there is a range of methods of possible killing techniques. The similarly-sized Rubidgea

44496-400: The use of this name in scientific literature dates back to the beginning of the 20th century, notably in the works of Friedrich von Huene and Edwin Ray Lankester . Taxonomic issues regarding the original naming of the genus are the subject of a study which should be published later. Although the etymology of the genus and type species is not provided in the earliest-known descriptions of

44712-410: The validity of the taxa erected by Pravoslavlev and describes a third species of Inostrancevia , I. uralensis , on the basis of part of the skull. The holotype specimen, cataloged as PIN 2896/1, consists of a left basioccipital having been discovered in the locality of Blumental-3, located in the Orenburg Oblast . The specific name uralensis refers to the Ural River , where the holotype specimen of

44928-530: The wider scientific community of his theory. Cuvier was a well-regarded geologist, lauded for his ability to reconstruct the anatomy of an unknown species from a few fragments of bone. His primary evidence for extinction came from mammoth skulls found in the Paris basin . Cuvier recognized them as distinct from any known living species of elephant, and argued that it was highly unlikely such an enormous animal would go undiscovered. In 1812, Cuvier, along with Alexandre Brongniart and Geoffroy Saint-Hilaire , mapped

45144-425: Was difficult to disprove. When parts of the world had not been thoroughly examined and charted, scientists could not rule out that animals found only in the fossil record were not simply "hiding" in unexplored regions of the Earth. Georges Cuvier is credited with establishing the modern conception of extinction in a 1796 lecture to the French Institute , though he would spend most of his career trying to convince

45360-403: Was discovered in the village of Zavrazhye , located in Vladimir Oblast . The specific name latifrons comes from the Latin latus "broad" and frōns "forehead", in reference to the size and the more robust cranial constitution than that of I. alexandri . In 1974, Leonid Petrovich Tatarinov carried out a large revision of the theriodonts then known in the USSR . In his work, he revises

45576-406: Was immediately classified in the family Gorgonopsidae after anatomical comparisons made with the type genus Gorgonops . This classification was maintained as such until 1948, when von Huene established a separate family of gorgonopsians, Inostranceviidae, to include Inostrancevia . Huene's opinion was generally shared in various studies published subsequently during the 20th century and even into

45792-401: Was named in 1968 in reference to the Road Canyon Member of the Word Formation in Texas. The GSSP for the base of the Roadian is located 42.7m above the base of the Cutoff Formation in Stratotype Canyon, Guadalupe Mountains, Texas, and was ratified in 2001. The beginning of the stage is defined by the first appearance of Jinogondolella nankingensis . The Wordian was named in reference to

46008-430: Was not until 1982, when David Raup and Jack Sepkoski published their seminal paper on mass extinctions, that Cuvier was vindicated and catastrophic extinction was accepted as an important mechanism . The current understanding of extinction is a synthesis of the cataclysmic extinction events proposed by Cuvier, and the background extinction events proposed by Lyell and Darwin. Extinction is an important research topic in

46224-449: Was not until 2023 that Christian F. Kammerer and his colleagues made the first official description concerning these latter. Their descriptions unexpectedly confirm that these specimens belong to Inostrancevia , which is a significant first given that the genus was historically only reported in Russia. The specimens nevertheless possessed some differences allowing them to be distinguished from the Russian lineages, they were then classified in

46440-523: Was periodically flooded. The Paleoflora of much of European Russia at the time was dominated by a genus of peltaspermaceaen , Tatarina , and other related genera, followed by ginkgophytes and conifers . On the other hand, ferns were relatively rare and sphenophytes were only locally present. There are also hygrophyte and halophyte plants in coastal areas as well as conifers that are more resistant to drought and higher altitudes. The Upper Daptocephalus Assemblage Zone in South Africa would have been

46656-571: Was skeptical that catastrophic events of a scale large enough to cause total extinction were possible. In his geological history of the earth titled Hydrogeologie, Lamarck instead argued that the surface of the earth was shaped by gradual erosion and deposition by water, and that species changed over time in response to the changing environment. Charles Lyell , a noted geologist and founder of uniformitarianism , believed that past processes should be understood using present day processes. Like Lamarck, Lyell acknowledged that extinction could occur, noting

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