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Umzantsia
''Umzantsia'' is an extinct genus of limbed stegocephalians ('tetrapods', in the broad sense) from the Devonian of South Africa. It contains a single species, ''Umzantsia amazana''. The genus is based on ~360 million year old skull and shoulder bones from the Waterloo Farm lagerstätte, a locality on the south-eastern coast of South Africa. In the Devonian, this area of Gondwana was located within the Antarctic Circle. Together with the find of '' Tutusius umlambo'' from the same locality, this provides the first evidence that Devonian limbed vertebrates were not restricted to the tropics as was formerly believed, and suggests that they may have been global in distribution. Waterloo Farm fossils have been metamorphosed and intensely flattened, with the bone tissue replaced by secondary metamorphic mica that is partially altered to kaolinite and chlorite during uplift. They also provide the first evidence of Devonian limbed vertebrates from the continent of Africa, and only the sec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tutusius
''Tutusius'' is a genus of extinct tetrapod from the Devonian of South Africa, containing a single species, ''Tutusius umlambo''. It was described from the +/- 360 myo Gondwana locality of Waterloo Farm lagerstätte on the south-eastern coast of South Africa, which at the time was located within the Antarctic Circle. Together with the find of ''Umzantsia, Umzantsia amazana'' from the same locality, this provides the first evidence that Devonian tetrapods were not restricted to the tropics as was formerly believed, and suggests that they may have been global in distribution. Waterloo Farm fossils have been metamorphosed and intensely flattened, with the bone tissue replaced by secondary metamorphic mica that is partially altered to kaolinite and chlorite during uplift. They also provide the first evidence of Devonian tetrapods from the continent of Africa, and only the second and third such taxa from Gondwana. Taxonomy ''Tutusius umlambo'' is known from a single cleithrum (a bone o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waterloo Farm Lagerstätte
The Waterloo Farm lagerstätte is a Famennian lagerstätte in South Africa that constitutes the only known record of a near-polar Devonian coastal ecosystem. History and discovery The Waterloo Farm Lagerstätte is an approximately 360 million year old Famennian (latest Devonian) fossil-rich locality of the Witpoort Formation (Witteberg Group, Cape Supergroup) in Makhanda (former Grahamstown) within the Eastern Cape Province, South Africa. Before it’s discovery very little was known of life during the Famennian (see Late Devonian extinction) in what is now southern Africa . This is largely due to the fact that fossils in the Witpoort Formation generally occur in black anaerobically deposited metashale that rapidly degrades near surface and is therefore rarely seen in natural outcrop. As is the case with many other scientific discoveries, the discovery of Waterloo Farm was accidental. Uprisings against the apartheid system in South Africa had by the mid-1980s escalated to vi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stegocephalia
Stegocephali (often spelled Stegocephalia) is a group containing all four-limbed vertebrates. It is equivalent to a broad definition of Tetrapoda: under this broad definition, the term "tetrapod" applies to any animal descended from the first vertebrate with limbs and toes, rather than fins. This includes both the modern lineage of limbed vertebrates (the crown group, including modern amphibians, mammals, reptiles and birds) as well as a portion of the stem group, limbed vertebrates that evolved prior to the origin of the crown group. Members of the tetrapod stem group include the earliest limbed tetrapodomorphs such as '' Ichthyostega'' and ''Acanthostega,'' which evolved in the Devonian Period long before any modern form of tetrapod. Many paleontologists prefer a stricter definition of Tetrapoda which applies solely to the crown group, excluding earlier types of limbed tetrapodomorphs. Stegocephali was re-established to replace the broad definition of Tetrapoda, resolving t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrapod
Tetrapods (; ) are four-limbed vertebrate animals constituting the superclass Tetrapoda (). It includes extant and extinct amphibians, sauropsids ( reptiles, including dinosaurs and therefore birds) and synapsids (pelycosaurs, extinct therapsids and all extant mammals). Tetrapods evolved from a clade of primitive semiaquatic animals known as the Tetrapodomorpha which, in turn, evolved from ancient lobe-finned fish (sarcopterygians) around 390 million years ago in the Middle Devonian period; their forms were transitional between lobe-finned fishes and true four-limbed tetrapods. Limbed vertebrates (tetrapods in the broad sense of the word) are first known from Middle Devonian trackways, and body fossils became common near the end of the Late Devonian but these were all aquatic. The first crown-tetrapods (last common ancestors of extant tetrapods capable of terrestrial locomotion) appeared by the very early Carboniferous, 350 million years ago. The specific aquatic ancestors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, where rocks from this period were first studied. The first significant adaptive radiation of life on dry land occurred during the Devonian. Free-sporing vascular plants began to spread across dry land, forming extensive forests which covered the continents. By the middle of the Devonian, several groups of plants had evolved leaves and true roots, and by the end of the period the first seed-bearing plants appeared. The arthropod groups of myriapods, arachnids and hexapods also became well-established early in this period, after starting their expansion to land at least from the Ordovician period. Fish reached substantial diversity during this time, leading the Devonian to often be dubbed the Age of Fishes. The placoderms began dominating ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Africa
South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countries of Namibia, Botswana, and Zimbabwe; and to the east and northeast by Mozambique and Eswatini. It also completely enclaves the country Lesotho. It is the southernmost country on the mainland of the Old World, and the second-most populous country located entirely south of the equator, after Tanzania. South Africa is a biodiversity hotspot, with unique biomes, plant and animal life. With over 60 million people, the country is the world's 24th-most populous nation and covers an area of . South Africa has three capital cities, with the executive, judicial and legislative branches of government based in Pretoria, Bloemfontein, and Cape Town respectively. The largest city is Johannesburg. About 80% of the population are Black South Afri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gondwana
Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages of break-up, involving the separation of Antarctica from South America (forming the Drake Passage) and Australia, occurred during the Paleogene. Gondwana was not considered a supercontinent by the earliest definition, since the landmasses of Baltica, Laurentia, and Siberia were separated from it. To differentiate it from the Indian region of the same name (see ), it is also commonly called Gondwanaland. Gondwana was formed by the accretion of several cratons. Eventually, Gondwana became the largest piece of continental crust of the Palaeozoic Era, covering an area of about , about one-fifth of the Earth's surface. During the Carboniferous Period, it merged with Laurasia to form a larger supercontinent called Pangaea. Gondwana (and Pan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Circle
The Antarctic Circle is the most southerly of the five major circles of latitude that mark maps of Earth. The region south of this circle is known as the Antarctic, and the zone immediately to the north is called the Southern Temperate Zone. South of the Antarctic Circle, the Sun is above the horizon for 24 continuous hours at least once per year (and therefore visible at midnight) and the centre of the Sun (ignoring refraction) is below the horizon for 24 continuous hours at least once per year (and therefore not visible at noon); this is also true within the equivalent polar circle in the Northern Hemisphere, the Arctic Circle. The position of the Antarctic Circle is not fixed and currently runs south of the Equator. This figure may be slightly inaccurate because it does not allow for the effects of astronomical nutation, which can be up to 10″. Its latitude depends on the Earth's axial tilt, which fluctuates within a margin of more than 2° over a 41,000-year period, due ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tropics
The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to as the tropical zone and the torrid zone (see geographical zone). In terms of climate, the tropics receive sunlight that is more direct than the rest of Earth and are generally hotter and wetter as they aren't affected as much by the solar seasons. The word "tropical" sometimes refers to this sort of climate in the zone rather than to the geographical zone itself. The tropical zone includes deserts and snow-capped mountains, which are not tropical in the climatic sense. The tropics are distinguished from the other climatic and biomatic regions of Earth, which are the middle latitudes and the polar regions on either side of the equatorial zone. The tropics constitute 40% of Earth's surface area and contain 36% of Earth's landmass. , the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IsiXhosa
Xhosa (, ) also isiXhosa as an endonym, is a Nguni language and one of the official languages of South Africa and Zimbabwe. Xhosa is spoken as a first language by approximately 8.2 million people and by another 11 million as a second language in South Africa, mostly in Eastern Cape, Western Cape, Northern Cape and Gauteng. It has perhaps the heaviest functional load of click consonants in a Bantu language (approximately tied with Yeyi), with one count finding that 10% of basic vocabulary items contained a click. Classification Xhosa is part of the branch of Nguni languages, which also include Zulu, Southern Ndebele and Northern Ndebele. Nguni languages effectively form a dialect continuum of variously mutually intelligible varieties. Xhosa is, to some extent, mutually intelligible with Zulu and with other Nguni languages to a lesser extent. Nguni languages are, in turn, classified under the much larger abstraction of Bantu languages. Geographical distribution ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cleithrum
The cleithrum (plural cleithra) is a membrane bone which first appears as part of the skeleton in primitive bony fish, where it runs vertically along the scapula. Its name is derived from Greek κλειθρον = " key (lock)", by analogy with "clavicle" from Latin ''clavicula'' = "little key". In modern fishes, the cleithrum is a large bone that extends upwards from the base of the pectoral fin and anchors to the cranium above the gills, forming the posterior edge of the gill chamber. The bone has scientific use as a means to determine the age of fishes. The lobe-finned fishes share this arrangement. In the earliest amphibians however, the cleithrum/clavicle complex came free of the skull roof, allowing for a movable neck. The cleithrum disappeared early in the evolution of reptiles, and in amniotes is very small or absent. It has been argued based on position, muscle connectivity, and developmental origin that the nuchal element of the turtle carapace A carapace is a Dors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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