|
Dicroidium
''Dicroidium'' is an extinct genus of fork-leaved seed ferns that were widely distributed over Gondwana during the Triassic (). Their fossils are known from South Africa, the Arabian Peninsula, Australia, New Zealand, South America, Madagascar, the Indian subcontinent and Antarctica. They were first discovered in Triassic sediments of Tasmania by Morris in 1845. Fossils from the Umm Irna Formation in Jordan and in Pakistan indicate that these plants already existed in Late Permian. Late surviving members of the genus are known from the Early Jurassic (Sinemurian) of East Antarctica. Within paleobotany, ''Dicroidium'' is a form genus used to refers to the leaves, associated with ovuluate organs classified as '' Umkomasia'' and pollen organs classified as '' Pteruchus,'' while ''Dicroidum'' is also used collectively to refer to the whole plant. Description The leaves are similar to those of modern ferns but like all seed ferns (Pteridospermatophyta The term Pteridospermat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dicroidium Zuberi Leaf
''Dicroidium'' is an extinct genus of fork-leaved seed ferns that were widely distributed over Gondwana during the Triassic (). Their fossils are known from South Africa, the Arabian Peninsula, Australia, New Zealand, South America, Madagascar, the Indian subcontinent and Antarctica. They were first discovered in Triassic sediments of Tasmania by Morris in 1845. Fossils from the Umm Irna Formation in Jordan and in Pakistan indicate that these plants already existed in Late Permian. Late surviving members of the genus are known from the Early Jurassic (Sinemurian) of East Antarctica. Within paleobotany, ''Dicroidium'' is a form genus used to refers to the leaves, associated with ovuluate organs classified as '' Umkomasia'' and pollen organs classified as '' Pteruchus,'' while ''Dicroidum'' is also used collectively to refer to the whole plant. Description The leaves are similar to those of modern ferns but like all seed ferns (Pteridospermatophyta The term Pteridospermat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dicroidium Zuberi
''Dicroidium zuberi'' is a large bipinnate species of the seed fern ''Dicroidium'' with a forked rachis In biology, a rachis (from the grc, ῥάχις [], "backbone, spine") is a main axis or "shaft". In zoology and microbiology In vertebrates, ''rachis'' can refer to the series of articulated vertebrae, which encase the spinal cord. In this c .... The leaves are affiliated with ''Umkomasia feistmantellii'' megasporophylls and ''Petruchus'' ''barrealensis'' microsporophylls. ''D. zuberi'' was a common species in the coeval vegetation of the Sydney and Lorne Basins of New South Wales. Specimens have been found near Wairaki Hut and indicate that this species may have been as common in Scytho-Anisian vegetation of coastal New Zealand. In younger rocks younger than the late Anisian, they are outnumbered by unipinnate ''Dicroidium'' leaves such as those belonging to ''D. odontopteroides''. Description ''Dicroidium zuberi'' had large, bipinnate, thick and leathery leaves. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dicroidium Odontopteroides
''Dicroidium odontopteroides'' was a common and widespread species of ''Dicroidium'' known from South Africa, Australia, New Zealand, South America and Antarctica. The species was first discovered in Triassic sediments of Tasmania and described by the palaeontologist John Morris in 1845. Description The leaves of ''Dicroidium odontopteroides'' differ from other species of ''Dicroidium ''Dicroidium'' is an extinct genus of fork-leaved seed ferns that were widely distributed over Gondwana during the Triassic (). Their fossils are known from South Africa, the Arabian Peninsula, Australia, New Zealand, South America, Madagascar ...'' in being unipinnate and having short rounded pinnae. Whole plant reconstructions ''Dicroidium odontopteroides'' may have been produced by the same plant as '' Umkomasia macleanii'' (ovulate structures) and '' Pteruchus africanus'' (pollen organs), based on cuticular similarities between these leaves and reproductive structures at the Umkomaas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pteruchus
''Pteruchus'' is a form genus for pollen organs of the seed fern (Pteridospermatophyta family Umkomasiaceae. It was first described by Hamshaw Thomas from the Umkomaas locality of South Africa. It is associated with the seed bearing organs '' Umkomasia'' and ''Dicroidium'' leaves. Description The pollen organ ''Pteruchus'' differs from other seed fern pollen organs in having numerous pendant pollen sacs from a blade-like head, in an arrangement similar to an epaulette. Whole plant reconstructions *'' Pteruchus africanus'' may have been produced by the same plant as '' Umkomasia macleanii'' (ovulate organs) and ''Dicroidium odontopteroides'' (leaves), based on cuticular similarities between these leaves and reproductive structures at the Umkomaas locality of South Africa. *'' Pteruchus barrealensis'' may have been produced by the same plant as '' Umkomasia feistmantelii'' (ovulate organs) and ''Dicroidium zuberi ''Dicroidium zuberi'' is a large bipinnate species of the se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Umkomasia
''Umkomasia'' is a genus of seed bearing organs produced by corystosperm seed ferns, first based on fossils collected by Hamshaw Thomas from the Burnera Waterfall locality near the Umkomaas River of South Africa. He recognized on the basis of cuticular similarities that the same plant produced pollen organs ''Pteruchus'' and the leaves ''Dicroidium''. Various other corystosperm seed bearing organs from the Jurassic and Cretaceous have been assigned to this genus, but recently have been given distinct genera, with ''Umkomasia'' being restricted to the Triassic. Description Umkomasia has helmet like cupules around ovules born in complex large branching structures. Whole plant associations *'' Umkomasia feistmantelii'' from the Early Triassic of Australia may have been produced by the same plant as '' Pteruchus barrealensis'' (pollen organs) and ''Dicroidium zuberi'' (leaves) *''Umkomasia macleanii'' from the Late Triassic of South Africa may have been produced by the sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pteruchus Africanus
''Pteruchus africanus'' is a pollen organ of a seed fern (Pteridospermatophyta). It was first described by Hamshaw Thomas from the Umkomaas locality of South Africa. Description The pollen organs ''Pteruchus africanus'' differ from other species of ''Pteruchus'' in small size, and equant blade supporting the pollen sacs. Whole plant reconstructions ''Pteruchus africanus'' may have been produced by the same plant as '' Umkomasia macleanii'' (ovulate organs) and ''Dicroidium odontopteroides ''Dicroidium odontopteroides'' was a common and widespread species of ''Dicroidium'' known from South Africa, Australia, New Zealand, South America and Antarctica. The species was first discovered in Triassic sediments of Tasmania and described ...'' (leaves), based on cuticular similarities between these leaves and reproductive structures at the Umkomaas locality of South Africa. References Triassic plants Pteridospermatophyta {{triassic-plant-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Umkomasia Macleanii
''Umkomasia macleanii'' is an ovulate structure of a seed fern (Pteridospermatophyta The term Pteridospermatophyta (or "seed ferns" or "Pteridospermatopsida") is a polyphyletic group of extinct seed-bearing plants (spermatophytes). The earliest fossil evidence for plants of this type is the genus ''Elkinsia'' of the late Devonia ... and the nominate genus of Family Umkomasiaceae. It was first described by Hamshaw Thomas from the Umkomaas locality of South Africa. Description The ovulate structures of ''Umkomasia macleanii'' differ from other species of '' Umkomasia'' in small size, and limited geographic distribution. Whole plant reconstructions ''Umkomasia macleanii'' may have been produced by the same plant as '' Pteruchus africanus'' (pollen organs) and '' Dicroidium odontopteroides'' (leaves), based on cuticular similarities between these leaves and reproductive structures at the Umkomaas locality of South Africa. References Triassic plants Pteridospermatop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pteruchus Barrealensis
''Pteruchus barrealensis'' is an unusually large species of ''Pteruchus'' with very elongate polleniferous heads from Early Triassic of Australia and Argentina. Description ''Pteruchus barrealensis'' is one of the geologically earliest species of ''Pteruchus'', and has very elongate polleniferous heads. Whole plant reconstruction ''Pteruchus barrealensis'' from the Early Triassic of Australia may have been produced by the same plant as '' Umkomasia feistmantelii'' (ovulate organs) and ''Dicroidium zuberi ''Dicroidium zuberi'' is a large bipinnate species of the seed fern ''Dicroidium'' with a forked rachis In biology, a rachis (from the grc, ῥάχις [], "backbone, spine") is a main axis or "shaft". In zoology and microbiology In verteb ...'' (leaves) References Triassic plants Pteridospermatophyta {{triassic-plant-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Umkomasia Feistmantelii
''Umkomasia feistmantelii'' is an unusually large species of ''Umkomasia'' from the Early Triassic of New South Wales, Australia. Description ''Umkomasia feistmantelii'' is found both with cupules enclosing the large seeds and with cupules open and expandede into a star-shaped form. Whole Plant Reconstruction ''Umkomasia feistmantelii'' from the Early Triassic of Australia may have been produced by the same plant as ''Pteruchus barrealensis'' (pollen organs) and ''Dicroidium zuberi ''Dicroidium zuberi'' is a large bipinnate species of the seed fern ''Dicroidium'' with a forked rachis In biology, a rachis (from the grc, ῥάχις [], "backbone, spine") is a main axis or "shaft". In zoology and microbiology In verteb ...'' (leaves) See also * Evolution of plants References External links Paleodb.org: ''Umkomasia feistmanteli'' Permian plants Triassic plants Pteridospermatophyta Cisuralian life Early Triassic life Plants described in 1987 Cis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest continent, being about 40% larger than Europe, and has an area of . Most of Antarctica is covered by the Antarctic ice sheet, with an average thickness of . Antarctica is, on average, the coldest, driest, and windiest of the continents, and it has the highest average elevation. It is mainly a polar desert, with annual precipitation of over along the coast and far less inland. About 70% of the world's freshwater reserves are frozen in Antarctica, which, if melted, would raise global sea levels by almost . Antarctica holds the record for the lowest measured temperature on Earth, . The coastal regions can reach temperatures over in summer. Native species of animals include mites, nematodes, penguins, seals and tardigrades. Where ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Umm Irna Formation
The Umm Irna Formation is a geological formation in Jordan. It is found in several outcrops in Jordan in the area around the eastern shore of the Dead Sea. It is Late Permian (likely Changhsingian) in age, and is the oldest unit in the succession, overlying the Cambrian aged Umm Ishrin Sandstone Formation. The formation predominantly consists of sandstones, claystones and mudstones deposited in fluvial and lacustrine conditions. The formation is of considerable paleobotanical interest, as it preserves the earliest known remains of plant groups that would become widespread during the Mesozoic, including Corystosperm seed ferns, represented by the widespread Triassic genus ''Dicroidium,'' cycads (''cf. Ctenis''), podocarp conifers, as well as Bennettitales. Other plant groups present in the formation include Noeggerathiales Noeggerathiales is a now- extinct order of vascular plants. The fossil range of the order extends from the Upper Carboniferous to the upper Permian (Lopin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triassic
The Triassic ( ) is a geologic period and system (stratigraphy), system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Year#Abbreviations yr and ya, Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest period of the Mesozoic, Mesozoic Era. Both the start and end of the period are marked by major extinction events. The Triassic Period is subdivided into three epochs: Early Triassic, Middle Triassic and Late Triassic. The Triassic began in the wake of the Permian–Triassic extinction event, which left the Earth's biosphere impoverished; it was well into the middle of the Triassic before life recovered its former diversity. Three categories of organisms can be distinguished in the Triassic record: survivors from the extinction event, new groups that flourished briefly, and other new groups that went on to dominate the Mesozoic Era. Reptiles, especially archosaurs, were the chief terrestrial vert ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
