43-543: Patranomodon (from Greek πατρ- patr- “father”, thus “father of anomodonts”) is an extinct genus of therapsids belonging to the group Anomodontia . Rubidge and Hopson named this anomodont in 1990 after discovering its skull. Patranomodon is known to have ranged in the Karoo of Southern Africa. The skull fossil of Patranomodon was found in the Eodicynodon Assemblage Zone of South Africa , belonging to
86-574: A horn that extends to the jaw. The transition from its carnivorous ancestor to the herbivorous Patranomodon occurred rapidly compared to the longevity of the species of anomodonts. The environment during the Lopingian epoch of the Permian , when Patranomodon roamed the Earth, was typically aquatic-based, with plentiful precipitation concentrated in the mountains and plateaux of terrestrial habitats. Rainfall
129-406: A lineage of the eucynodont suborder. Biarmosuchia Dinocephalia Anomodontia Gorgonopsia Therocephalia Cynodontia Six major groups of therapsids are generally recognized: Biarmosuchia , Dinocephalia , Anomodontia , Gorgonopsia , Therocephalia and Cynodontia . A clade uniting therocephalians and cynodonts, called Eutheriodontia , is well supported, but relationships among
172-415: A shorter face compared to other anomodontons. This gives Patranomodon a shorter facial structure, shorter in length as well as small in size. They also have a reduced tabular, a slit-like interpterygoid vacuity, three sacral vertebrae , and a screw-shape jaw. The genus has many features indicating its herbivorous behavior: the division of the external adductor muscles in the jaw into two separate components,
215-491: A single opening behind the eye. They are distinguished from the Caseasaurian synapsids by having a long, narrow supratemporal bone (instead of one that is as wide as it is long) and a frontal bone with a wider connection to the upper margin of the orbit . The only living descendants of basal eupelycosaurs are the mammals . The group was originally considered a suborder of pelycosaurs or "mammal like reptiles", but it
258-432: Is Edaphosaurus , a large [10–12-foot-long (3.0–3.7 m)] herbivore which had a sail on its back, probably used for thermoregulation and mating. Sphenacodontids , a family of carnivorous eupelycosaurs, included the famous Dimetrodon , which is sometimes mistaken for a dinosaur , and was the largest predator of the period. Like Edaphosaurus , Dimetrodon also had a distinctive sail on its back, and it probably served
301-567: Is a large clade of animals characterized by the unique shape of their skull , encompassing all mammals and their closest extinct relatives. They first appeared 308 million years ago during the Early Pennsylvanian epoch, with the fossils of Echinerpeton and perhaps an even earlier genus, Protoclepsydrops , representing just one of the many stages in the evolution of mammals, in contrast to their earlier amniote ancestors. Eupelycosaurs are synapsids , animals whose skull has
344-609: The Carnian (Late Triassic), although they continued for some time longer in the wet equatorial band and the south. Some exceptions were the still further derived eucynodonts . At least three groups of them survived. They all appeared in the Late Triassic period. The extremely mammal -like family, Tritylodontidae , survived into the Early Cretaceous . Another extremely mammal-like family, Tritheledontidae , are unknown later than
387-527: The Theriodontia . Hopson and Barghausen did not initially come to a conclusion about how dinocephalians, anomodonts and theriodonts were related to each other, but subsequent studies suggested that anomodonts and theriodonts should be classified together as the Neotherapsida. However, there remains debate over these relationships; in particular, some studies have suggested that anomodonts, not gorgonopsians, are
430-551: The circadian rhythm of ectotherms, but is absent in modern mammals, which are endothermic . Near the end of the Permian, dicynodonts, therocephalians and cynodonts show parallel trends towards loss of the pineal foramen, and the foramen is completely absent in probainognathian cynodonts. Evidence from oxygen isotopes, which are correlated with body temperature, suggests that most Permian therapsids were ectotherms and that endothermy evolved convergently in dicynodonts and cynodonts near
473-401: The dinocephalians , the herbivorous anomodonts , the carnivorous biarmosuchians , and the mostly carnivorous theriodonts . After a brief burst of evolutionary diversity, the dinocephalians died out in the later Middle Permian ( Guadalupian ) but the anomodont dicynodonts as well as the theriodont gorgonopsians and therocephalians flourished, being joined at the very end of the Permian by
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#1733093987207516-438: The teeth were differentiated into frontal incisors for nipping, great lateral canines for puncturing and tearing, and molars for shearing and chopping food. Therapsid legs were positioned more vertically beneath their bodies than were the sprawling legs of reptiles and pelycosaurs. Also compared to these groups, the feet were more symmetrical, with the first and last toes short and the middle toes long, an indication that
559-655: The Early Jurassic . Mammaliaformes was the third group, including Morganucodon and similar animals. Some taxonomists refer to these animals as "mammals", though most limit the term to the mammalian crown group . The non-eucynodont cynodonts survived the Permian–Triassic extinction; Thrinaxodon , Galesaurus and Platycraniellus are known from the Early Triassic . By the Middle Triassic , however, only
602-583: The Early Permian of the United States has been hypothesized to be an even earlier-diverging therapsid, but more recent study has suggested it is more likely to be a non-therapsid sphenacodontian. Biarmosuchia is the most recently recognized therapsid clade, first recognized as a distinct lineage by Hopson and Barghausen in 1986 and formally named by Sigogneau-Russell in 1989. Most biarmosuchians were previously classified as gorgonopsians. Biarmosuchia includes
645-578: The Eastern Cape of South Africa; however, fossil parts were also found in Europe, China, as well as India, which indicated migration occurring among these terrestrial creatures. The paleontologist John Nyaphuli collected the fossil of this creature in South Africa and gave it the species name of " Patranomodon nyaphuli ". Patranomodon have a short exposure of their palatine and premaxilla , which creates
688-484: The Late Permian epoch, there was probably migration due to the progressive climatic drying and the shrinking of the basin. This migration occurred in a northward direction to warmer environments. Evidence for migration is also found in the distribution of fossils of certain anomodonts northward from the southern cape of Africa. The Beaufort Group , where Patranomodon was found in the fossil record, dominated most of
731-605: The aftermath of the Permian–Triassic extinction event , therapsids declined in relative importance to the rapidly diversifying archosaurian sauropsids ( pseudosuchians , dinosaurs and pterosaurs , etc.) during the Middle Triassic. The therapsids include the cynodonts , the group that gave rise to mammals ( Mammaliaformes ) in the Late Triassic around 225 million years ago, the only therapsid clade that survived beyond
774-439: The apparent attachment sites for turbinates may simply be the result of distortion of the skull. The evolution of integument in therapsids is poorly known, and there are few fossils that provide direct evidence for the presence or absence of fur. The most basal synapsids with unambiguous direct evidence of fur are docodonts , which are mammaliaforms very closely related to crown-group mammals. Two "mummified" juvenile specimens of
817-427: The basin with fluvial sedimentation. During the Permian period, Europe, Africa, Asia, America, and Antarctica were joined in one large supercontinent called Pangea. Scattered fossils of Anomodonts provide evidence for this huge land mass as well as for migration from one end of the land mass to the other. Fluvial sedimentation refers to the sediment carried by streams and rivers that deposit into landforms, thus preserving
860-582: The body, resulting in a more "standing" quadrupedal posture, as opposed to the lower sprawling posture of many reptiles and amphibians . Therapsids evolved from earlier synapsids commonly called " pelycosaurs ", specifically within the Sphenacodontia , more than 279.5 million years ago. They replaced the pelycosaurs as the dominant large land animals in the Guadalupian through to the Early Triassic. In
903-463: The dicynodont Lystrosaurus murrayi preserve skin impressions; the skin is hairless, leathery, and dimpled, somewhat comparable to elephant skin. Fossilized facial skin from the dinocephalian Estemmenosuchus has been described as showing that the skin was glandular and lacked both scales and hair. Coprolites containing what appear to be hairs have been found from the Late Permian . Though
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#1733093987207946-472: The distinctive Burnetiamorpha , but support for the monophyly of Biarmosuchia is relatively low. Many biarmosuchians are known for extensive cranial ornamentation. Dinocephalia comprises two distinctive groups, the Anteosauria and Tapinocephalia . Historically, carnivorous dinocephalians, including both anteosaurs and titanosuchids, were called titanosuchians and classified as members of Theriodontia, while
989-486: The dominant land animals from the latest Carboniferous to the end of the Early Permian epoch. Ophiacodontids were common from their appearance in the late Carboniferous ( Pennsylvanian ) to the early Permian, but they became progressively smaller as the early Permian progressed. The edaphosaurids , along with the caseids , were the dominant herbivores in the early part of the Permian. The most renowned edaphosaurid
1032-611: The end of the Triassic . The only other group of therapsids to have survived into the Late Triassic , the dicynodonts , became extinct towards the end of the period. The last surviving group of non-mammaliaform cynodonts were the Tritylodontidae , which became extinct during the Early Cretaceous . Therapsids' temporal fenestrae were larger than those of the pelycosaurs. The jaws of some therapsids were more complex and powerful, and
1075-459: The end of the Permian. In contrast, evidence from histology suggests that endothermy is shared across Therapsida, whereas estimates of blood flow rate and lifespan in the mammaliaform Morganucodon suggest that even early mammaliaforms had reptile-like metabolic rates. Evidence for respiratory turbinates, which have been hypothesized to be indicative of endothermy, was reported in the therocephalian Glanosuchus , but subsequent study showed that
1118-438: The eucynodonts remained. The therocephalians , relatives of the cynodonts, managed to survive the Permian–Triassic extinction and continued to diversify through the Early Triassic period. Approaching the end of the period, however, the therocephalians were in decline to eventual extinction, likely outcompeted by the rapidly diversifying Saurian lineage of diapsids , equipped with sophisticated respiratory systems better suited to
1161-471: The first of the cynodonts . Like all land animals, the therapsids were seriously affected by the Permian–Triassic extinction event , with the very successful gorgonopsians and the biarmosuchians dying out altogether and the remaining groups— dicynodonts , therocephalians and cynodonts —reduced to a handful of species each by the earliest Triassic . Surviving dicynodonts were represented by two families of disaster taxa ( Lystrosauridae and Myosauridae ),
1204-446: The foot's axis was placed parallel to that of the animal, not sprawling out sideways. This orientation would have given a more mammal -like gait than the lizard -like gait of the pelycosaurs. The physiology of therapsids is poorly understood. Most Permian therapsids had a pineal foramen, indicating that they had a parietal eye like many modern reptiles and amphibians. The parietal eye serves an important role in thermoregulation and
1247-431: The fossil skull of Patranomodon . These streams and rivers were most likely formed by ice masses such as glaciers. Therapsida Therapsida is a clade comprising a major group of eupelycosaurian synapsids that includes mammals and their ancestors and close relatives. Many of the traits today seen as unique to mammals had their origin within early therapsids, including limbs that were oriented more underneath
1290-631: The herbivorous Tapinocephalidae were classified as members of Anomodontia. Anomodontia includes the dicynodonts , a clade of tusked, beaked herbivores, and the most diverse and long-lived clade of non-cynodont therapsids. Other members of Anomodontia include Suminia , which is thought to have been a climbing form. Gorgonopsia is an abundant but morphologically homogeneous group of saber-toothed predators . It has been suggested that Therocephalia might not be monophyletic, with some species more closely related to cynodonts than others. However, most studies regard Therocephalia as monophyletic. Cynodonts are
1333-604: The lowest biozone of the Beaufort Group . The Beaufort Group time period extends from the middle of the Permian to the early Triassic period. It is one of the three main subdivisions of the Karoo Supergroup in what today is southern Africa. Rubidge and Hopson were the first to discover the skull of Patranomodon . These paleobiologists also named Patranomodon and were the first to publish literature on it starting in 1990. The most abundant remains of Patranomodon were found on
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1376-429: The medial and lateral side, as well as using a propalinal jaw movement while feeding on plant material. The teeth formation of Patranomodon allows crushing and grinding to occur as the jaws connect and move. Other aspects include widening of the palatal areas for breaking down plant matter in feeding, widening of the external adductors, the higher raised jaw hinge, reduction in the number and size of teeth, and acquiring
1419-475: The most diverse and longest-lived of the therapsid groups, as Cynodontia includes mammals . Cynodonts are the only major therapsid clade to lack a Middle Permian fossil record, with the earliest-known cynodont being Charassognathus from the Wuchiapingian age of the Late Permian. Non-mammalian cynodonts include both carnivorous and herbivorous forms. [REDACTED] Eupelycosauria Eupelycosauria
1462-509: The other four clades are controversial. The most widely accepted hypothesis of therapsid relationships, the Hopson and Barghausen paradigm, was first proposed in 1986. Under this hypothesis, biarmosuchians are the earliest-diverging major therapsid group, with the other five groups forming the Eutherapsida, and within Eutherapsida, gorgonopsians are the sister taxon of eutheriodonts, together forming
1505-500: The presence of foramina on the snout of therocephalians and early cynodonts, but the arrangement of foramina in these taxa actually closely resembles lizards, which would make the presence of mammal-like whiskers unlikely. Therapsids evolved from a group of pelycosaurs called sphenacodonts . Therapsids became the dominant land animals in the Middle Permian , displacing the pelycosaurs. Therapsida consists of four major clades :
1548-418: The same purpose - regulating heat. The varanopid family passingly resembled today's monitor lizards and may have had the same lifestyle. Therapsids descended from a clade closely related to the sphenacodontids. They became the succeeding dominant land animals for the rest of the Permian, and in the latter part of the Triassic , descendants of the cynodonts , an advanced group of therapsids, gave rise to
1591-564: The scarcely known Kombuisia , and a single group of large stocky herbivores , the Kannemeyeriiformes , which were the only dicynodont lineage to thrive during the Triassic. They and the medium-sized cynodonts (including both carnivorous and herbivorous forms) flourished worldwide throughout the Early and Middle Triassic. They disappear from the fossil record across much of Pangea at the end of
1634-440: The sister taxon of Eutheriodontia, other studies have found dinocephalians and anomodonts to form a clade, and both the phylogenetic position and monophyly of Biarmosuchia remain controversial. In addition to the six major groups, there are several other lineages and species of uncertain classification. Raranimus from the early Middle Permian of China is likely to be the earliest-diverging known therapsid. Tetraceratops from
1677-613: The source of these hairs is not known with certainty, they may suggest that hair was present in at least some Permian therapsids. The closure of the pineal foramen in probainognathian cynodonts may indicate a mutation in the regulatory gene Msx2, which is involved in both the closure of the skull roof and the maintenance of hair follicles in mice. This suggests that hair may have first evolved in probainognathians, though it does not entirely rule out an earlier origin of fur. Whiskers probably evolved in probainognathian cynodonts. Some studies had inferred an earlier origin for whiskers based on
1720-443: The terrestrial species evolved greatly after the mass extinction. Patranomodon was one of the early terrestrial species that evolved from the fully aquatic environments. Flash floods were the main reason why there were sediment deposits, along with overflowing rivers from melting ice caps. Fossilization requires specific factors that allow preservation of hard tissues such as bone. In southern Africa, where Patranomodon lived during
1763-568: The very hot, dry and oxygen-poor world of the End-Triassic. Dicynodonts were among the most successful groups of therapsids during the Late Permian, and survived through to near the end of the Triassic. Mammals are the only living therapsids. The mammalian crown group , which evolved in the Early Jurassic period, radiated from a group of mammaliaforms that included the docodonts . The mammaliaforms themselves evolved from probainognathians ,
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1806-439: Was redefined in 1997, and the term pelycosaur itself has fallen into disfavor. We now know that the eupelycosaurs were not in fact reptiles nor of reptile lineage - the modern term stem mammal is used instead. Some recent studies suggested that one of its subgroups, Varanopidae , are really nested within sauropsids , leaving the other defined subgroup of it, Metopophora , as its synonym. Many non-therapsid eupelycosaurs were
1849-415: Was very frequent during this time. There were times of warm humid greenhouse-like climate with soil erosion and stagnation in the wetlands, which may have led to the mass extinctions in middle to late Permian times. These environmental conditions created harsh living conditions for terrestrial creatures, some of which died off. The mass extinction affected most of the terrestrial and aquatic species; however,
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