taxon_rank tritheledontidae
Theria ( Greek : "  ", wild beast ) is a ___MASK93___ of mammals amongst the Theriiformes ( the sister taxa to Yinotheria ). Theria includes the eutherians ( including the placental mammals ) and the metatherians ( including the marsupials ). Birds ( Aves ), also known as avian dinosaurs , are a ___MASK25___ of endothermic vertebrates , characterised by feathers , toothless beaked jaws , the laying of hard - shelled eggs , a high metabolic rate , a four - chambered heart , and a lightweight but strong skeleton . Birds live worldwide and range in size from the bee hummingbird to the ostrich . They rank as the class of tetrapods with the most living ___MASK18___ , at approximately ten thousand , with more than half of these being passerines , sometimes known as perching birds or , less accurately , as songbirds . The neocortex , also called the neopallium and isocortex , is the part of the mammalian brain involved in higher - ___MASK43___ brain functions such as sensory perception , cognition , generation of motor commands , spatial reasoning and language . The Jurassic ( from Jura Mountains ) is a geologic period and system that spans 56 . 3 million years from the end of the Triassic Period million years ago ( Mya ) to the beginning of the Cretaceous Period Mya . The Jurassic constitutes the middle period of the Mesozoic Era , also known as the Age of Reptiles . The start of the period is marked by the major Triassic  Jurassic extinction event . Two other extinction events occurred during the period : the Pliensbachian / Toarcian event in the Early Jurassic , and the Tithonian event at the end ; however , neither event ranks among the " Big Five " mass extinctions . The Early Jurassic epoch ( in chronostratigraphy corresponding to the Lower Jurassic ___MASK26___ ) is the earliest of three epochs of the Jurassic period . The Early Jurassic starts immediately after the Triassic - Jurassic extinction event , 201 . 3 Ma ( million years ago ), and ends at the start of the Middle Jurassic 174 . 1 Ma . In geology , a supercontinent is the assembly of most or all of Earth ' s continental blocks or cratons to ___MASK53___ a single large landmass . However , the definition of a supercontinent can be ambiguous . Many earth scientists , such as P . F . Hoffman ( 1999 ), use the term " supercontinent " to mean " a clustering of nearly all continents ". This definition leaves room for interpretation when labeling a continental body and is easier to apply to Precambrian times . Using the first definition provided here , Gondwana ( a . k . a . Gondwanaland ) is not considered a supercontinent , because the landmasses of Baltica , Laurentia and Siberia also existed at the same time but physically separate from each other . The landmass of Pangaea is the collective name describing all of these continental masses when they were in proximity to one another . This would classify Pangaea as a supercontinent . According to the definition by Rogers and Santosh ( 2004 ), a supercontinent does not exist today . Supercontinents have assembled and dispersed multiple times in the geologic past ( see table ). The positions of continents have been accurately determined back to the early Jurassic . However , beyond , continental positions are much less certain . Mammals are any vertebrates within the ___MASK38___ Mammalia ( from Latin " mamma " " breast "), a clade of endothermic amniotes distinguished from reptiles and birds by the possession of a neocortex ( a region of the brain ), hair , three middle ear bones and mammary glands . The sister ___MASK25___ of mammals may be the extinct " Haldanodon ." The mammals represent the only living Synapsida , which together with the Sauropsida form the Amniota clade . The mammals consist of the Yinotheria including monotrema and the Theriiformes including the theria . In biology and ecology , extinction is the end of an organism or of a ___MASK25___ of organisms ( taxon ), normally a ___MASK18___ . The moment of extinction is generally considered to be the death of the last individual of the ___MASK18___ , although the capacity to breed and recover may have been lost before this point . Because a ___MASK18___ ' 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 ___MASK18___ presumed extinct abruptly " reappears " ( typically in the fossil record ) after a period of apparent absence . The Triassic  Jurassic extinction event marks the boundary between the Triassic and Jurassic periods , , and is one of the major extinction events of the Phanerozoic eon , profoundly affecting life on land and in the oceans . In the seas , a whole ___MASK38___ ( conodonts ) and 34 % of marine genera disappeared . On land , all pseudosuchians ( non - ornithodiran archosaurs ) other than crocodylomorphs ( Sphenosuchia and Crocodyliformes ), some remaining therapsids , and many of the large amphibians became extinct . The Tritheledontidae or tritheledontids , also known as ictidosaurs , were small to medium - sized ( about 10 or 20 cm long ) cynodonts . They were extremely mammal - like , highly specialized cynodonts , although they still retained a very few reptilian anatomical traits . Tritheledontids were mainly carnivorous or insectivorous , though some ___MASK18___ may have developed omnivorous traits . Their skeletons show that they had a close relationship to mammals . Tritheledontids or their closest relatives may have given rise to primitive mammals . The tritheledontids were one of the longest lived non - mammalian therapsid lineages , living from late Triassic to the Jurassic period . Tritheledontids became extinct in the Jurassic period , possibly due to competition with prehistoric mammals such as the triconodonts . They are known from finds in South America and South Africa , indicating that they may have lived only on the supercontinent of Gondwana . The ___MASK27___ Tritheledontidae was named by South African paleontologist Robert Broom in 1912 . The ___MASK27___ is often misspelled `` Trithelodontidae '' . It is possible that Tritheledontidae had vibrissae , according to the PBS documentary , Your Inner Fish . A common ancestor of all therian mammals did so . It is possible that the development of the whisker sensory system played an important role in mammalian development , more generally . Synapsids ( Greek , ' fused arch '), synonymous with theropsids ( Greek , ' beast - face '), are a ___MASK25___ of animals that includes mammals and every animal more closely related to mammals than to other living amniotes . They are easily separated from other amniotes by having a temporal fenestra , an opening low in the skull roof behind each eye , leaving a bony arch beneath each ; this accounts for their name . Primitive synapsids are usually called pelycosaurs or pelycosaur - grade synapsids ; more advanced mammal - like ones , therapsids . The non - mammalian members are described as mammal - like reptiles in classical systematics ; they can also be called stem mammals or proto - mammals . Synapsids evolved from basal amniotes and are one of the two major groups of the later amniotes ; the other is the sauropsids , a ___MASK25___ that includes modern reptiles and birds . The distinctive temporal fenestra developed in the ancestral synapsid about 312 million years ago , during the Late Carboniferous period . Rats are various medium - sized , long - tailed rodents of the ___MASK21___ Muroidea . " True rats " are members of the ___MASK3___ " Rattus ", the most important of which to humans are the black rat , " Rattus rattus ", and the brown rat , " Rattus norvegicus ". Many members of other rodent genera and families are also referred to as rats , and share many characteristics with true rats . Therapsida is a ___MASK25___ of synapsids that includes mammals and their ancestors . Many of the traits today seen as unique to mammals had their origin within early therapsids , including having their four limbs extend vertically beneath the body , as opposed to the sprawling posture of other reptiles . The earliest fossil attributed to Therapsida is " Tetraceratops insignis " from the Lower Permian . Robert Broom FRS FRSE ( 30 November 1866 , Paisley  6 April 1951 ) was a Scottish South African doctor and paleontologist . He qualified as a medical practitioner in 1895 and received his DSc in 1905 from the University of Glasgow . South Africa , officially the Republic of South Africa ( RSA ), is the southernmost country in Africa . It is bounded on the south by of coastline of Southern Africa stretching along the South Atlantic and Indian Oceans , on the north by the neighbouring countries of Namibia , Botswana and Zimbabwe , and on the east and northeast by Mozambique and Swaziland , and surrounding the ___MASK7___ of Lesotho . South Africa is the 25th - largest country in the world by land area , and with close to 56 million people , is the world ' s 24th - most populous nation . It is the southernmost country on the mainland of the Old World or the Eastern Hemisphere . It is the only country that borders both the Atlantic Ocean and the Indian Ocean . About 80 percent of South Africans are of Sub - Saharan African ancestry , divided among a ___MASK35___ of ethnic groups speaking different Bantu languages , nine of which have official status . The remaining population consists of Africa ' s largest communities of European ( white ), Asian ( Indian ), and multiracial ( coloured ) ancestry . South America is a continent located in the western hemisphere , mostly in the southern hemisphere , with a relatively small portion in the northern hemisphere . It is also considered a subcontinent of the Americas , which is the model used in nations that speak Romance languages . The reference to South America instead of other regions ( like Latin America or the Southern Cone ) has increased in the last decades due to changing geopolitical dynamics ( in particular , the rise of Brazil ). The Triassic is a geologic period and system which spans 50 . 9 million years from the end of the Permian Period million years ago ( Mya ), to the beginning of the Jurassic Period Mya . The Triassic is the first period of the Mesozoic Era . Both the start and end of the period are marked by major extinction events . The Triassic was named in 1834 by Friedrich von Alberti , after the three distinct rock layers (" tri " meaning " three ") that are found throughout Germany and northwestern Europe  red beds , capped by marine limestone , followed by a ___MASK26___ of terrestrial mud - and sandstones  called the " Trias ". Reptiles are tetrapod ( four - limbed vertebrate ) animals in the ___MASK38___ Reptilia , comprising today ' s turtles , crocodilians , snakes , amphisbaenians , lizards , tuatara , and their extinct relatives . The study of these traditional reptile orders , historically combined with that of modern amphibians , is called herpetology . Lesotho , officially the ___MASK7___ of Lesotho , is an enclaved , landlocked country in southern Africa completely surrounded by South Africa . It is just over in size and has a population slightly over two million . Its capital and largest city is Maseru . Tin is a chemical element with the symbol Sn ( for ) and atomic number 50 , is a post - transition metal in ___MASK25___ 14 of the periodic table . It is obtained chiefly from the mineral cassiterite , which contains tin dioxide , SnO . Tin shows a chemical similarity to both of its neighbors in ___MASK25___ 14 , germanium and lead , and has two main oxidation states , + 2 and the slightly more stable + 4 . Tin is the 49th most abundant element and has , with 10 stable isotopes , the largest number of stable isotopes in the periodic table , thanks to its magic number of protons . It has two main allotropes : at room temperature , the stable allotrope is  - tin , a silvery - white , malleable metal , but at low temperatures it transforms into the less dense grey  - tin , which has the diamond cubic structure . Metallic tin is not easily oxidized in air . Vertebrates comprise all ___MASK18___ of animals within the ___MASK61___ Vertebrata ( chordates with backbones ). Vertebrates represent the overwhelming majority of the phylum Chordata , with currently about 64 , 000 ___MASK18___ described . Vertebrates include the jawless fish and the jawed vertebrates , which include the cartilaginous fish ( sharks and rays ) and the bony fish . Sauropsida (" lizard faces ") is a ___MASK25___ of amniotes that includes all existing birds and reptiles as well as their fossil ancestors and other extinct relatives . Large land animals are either in this ___MASK25___ or in its sister ___MASK25___ , Synapsida , which includes mammals and their fossil relatives . This clade includes Parareptilia and other extinct clades . All living sauropsids are members of the sub - ___MASK25___ Diapsida , the Parareptilia clade having died out 200 million years ago . The term originated in 1864 with Thomas Henry Huxley , who grouped birds with reptiles based on fossil evidence . Brazil , officially the Federative Republic of Brazil , is the largest country in both South America and Latin America . As the world ' s fifth - largest country by both area and population , it is the largest country to have Portuguese as an official language and the only one in the Americas . Bounded by the Atlantic Ocean on the east , Brazil has a coastline of . It borders all other South American countries except Ecuador and Chile and covers 47 . 3 % of the continent ' s land area . Its Amazon River basin includes a vast tropical forest , home to diverse wildlife , a ___MASK35___ of ecological systems , and extensive natural resources spanning numerous protected habitats . This unique environmental heritage makes Brazil one of 17 megadiverse countries , and is the subject of significant global interest and debate regarding deforestation and environmental protection . Swaziland , officially the ___MASK7___ of Swaziland ( or ; Swazi : " Umbuso weSwatini " ; sometimes called kaNgwane or Eswatini ), is a sovereign state in Southern Africa . It is neighboured by Mozambique to its northeast and by South Africa to its north , west and south . The country and its people take their names from Mswati II , the 19th - century king under whose rule Swazi territory was expanded and unified . Trithelodon was an extinct ___MASK3___ of cynodontian therapsid that lived during the Lower Jurassic in modern South Africa . Like cynodonts , it had many traits shared by mammals . Trithelodonts were probably insectivores , and nocturnal animals . A mammary gland is an exocrine gland in mammals that produces milk to feed young offspring . Mammals get their name from the word " mammary ". The mammary glands are arranged in organs such as the breasts in primates ( for example , humans and chimpanzees ), the udder in ruminants ( for example , cows , goats , and deer ), and the dugs of other animals ( for example , dogs and cats ). Lactorrhea , the occasional production of milk by the glands , can occur in any mammal , but in most mammals lactation , the production of enough milk for nursing , occurs only in phenotypic females who have gestated in recent months or years . It is directed by hormonal guidance from sex steroids . In a few mammalian ___MASK18___ , male lactation can occur . Laurentia or the North American Craton is a large continental craton that forms the ancient geological core of the North American continent . Many times in its past , Laurentia has been a separate continent as it is now in the ___MASK53___ of North America , although originally it also included the cratonic areas of Greenland and also the northwestern part of Scotland , known as the Hebridean Terrane . During other times in its past , Laurentia has been part of larger continents and supercontinents and itself consists of many smaller terranes assembled on a network of Early Proterozoic orogenic belts . Small microcontinents and oceanic islands collided with and sutured onto the ever - growing Laurentia , and together formed the stable Precambrian craton seen today . Theriiformes is a ___MASK93___ of mammals . The term was coined in 1997 by McKenna & Bell in their classification of mammals . Latin America is a ___MASK25___ of countries and dependencies in the Americas where Romance languages are predominant . The term originated in 19th century France as " Amérique latine " to consider French - speaking territories in the Americas ( Haiti , French Guiana , Martinique , Guadeloupe , Saint Martin , Saint Barthélemy ) along with the larger ___MASK25___ of countries where Spanish and Portuguese languages prevailed . It is therefore broader than the terms Ibero - America or Hispanic America  though it usually excludes French Canada and modern French Louisiana . The Bantu languages , technically the Narrow Bantu languages ( as opposed to " Wide Bantu ", a loosely defined categorization which includes other Bantoid languages ), constitute a traditional ___MASK73___ of the Niger  Congo languages . There are about 250 Bantu languages by the criterion of mutual intelligibility , though the distinction between language and dialect is often unclear , and " Ethnologue " counts 535 languages . Bantu languages are spoken largely east and south of present - day Cameroon , that is , in the regions commonly known as Central Africa , Southeast Africa , and Southern Africa . Parts of the Bantu area include languages from other language families ( see map ). In the geological timescale the Tithonian is the latest age of the Late Jurassic epoch or the uppermost stage of the Upper Jurassic ___MASK26___ . It spans the time between 152 . 1 ± 4 Ma and 145 . 0 ± 4 Ma ( million years ago ). It is preceded by the Kimmeridgian and followed by the Berriasian stage ( part of the Cretaceous ). A clade ( from , " klados ", " ___MASK73___ ") is a ___MASK25___ of organisms that consists of a common ancestor and all its lineal descendants , and represents a single " ___MASK73___ " on the " tree of life ". The University of Glasgow ( abbreviated as Glas . in post - nominals ) is the fourth oldest university in the English - speaking world and one of Scotland ' s four ancient universities . It was founded in 1451 . Along with the University of Edinburgh , the University was part of the Scottish Enlightenment during the 18th century . It is currently a member of Universitas 21 , the international network of research universities , and the Russell ___MASK25___ . The Romance languages ( sometimes called the Romanic languages , Latin languages , or Neo - Latin languages ) are the modern languages that evolved from Vulgar Latin between the sixth and ninth centuries and that thus ___MASK53___ a ___MASK73___ of the Italic languages within the Indo - European language ___MASK27___ .