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Corystosperm
Corystosperms are a group of extinct seed plants (often referred to as "seed ferns") belonging to the family Corystospermaceae (also called Umkomasiaceae) assigned to the order Corystospermales or Umkomasiales. They were first described based on fossils collected by Hamshaw Thomas from the Burnera Waterfall locality near the Umkomaas River of South Africa. Corystosperms are typified by a group of plants that bore forked ''Dicroidium'' leaves, ''Umkomasia'' cupulate ovulate structures and ''Pteruchus'' pollen organs, which grew as trees that were widespread over Gondwana during the Middle and Late Triassic. Other fossil Mesozoic seed plants with similar leaf and/or reproductive structures have also sometimes been included within the "corystosperm" concept ''sensu lato'', such as the "doyleoids" from the Early Cretaceous of North America and Asia. A potential corystosperm ''sensu lato'', the leaf genus ''Komlopteris'', is known from the Eocene of Tasmania, around 53-50 million years ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Komlopteris
''Komlopteris'' is an extinct genus of "seed fern" with possible corystosperm affinities. Fossils have been found across both hemispheres, dating from the latest Triassic to the early Eocene (Ypresian), making it the youngest "seed fern" in the fossil record. Morphology Within the form classification system used in paleobotany, ''Komlopteris'' is used to refer to leaves. The leaves are generally lanceolate to slightly falcate, though some are Ovate (botany), ovate, and form a Pinnation, pinnate arrangement, and are sometimes bipinnate. The cuticles are thick, with at least some having resin bodies within the leaves. Ecology Gondwanan ''Komlopteris'' species are often associated with fern dominated, humid temperate forested habitats. The finding of numerous leaves of ''Komlopteris'' in single leaf mat layers suggests that at least some species were deciduous. A 1998 study suggested that the type species ''Komlopteris nordenskioeldii'' likely grew as a tree, based on the presenc ... [...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] |
Dicroidium
''Dicroidium'' is an extinct genus of fork-leaved seed plants. It is the archetypal genus of the corystosperms, an extinct group of seed plants, often called " seed ferns", assigned to the order Corystospermales or Umkomasiales. Species of ''Dicroidium,'' which grew as large trees, were widely distributed and dominant 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. Description Within the form genus classification system used in paleobotany, the genus ''Dicroidium'' refers specifically to the leaves. Some authors have suggested dividing ''Dicroidium'' up into several genera, including ''Dicroidiopsis, Diplasiophyllum, Zuberia'', ''Xylopteris'', ''Johnstonia'' and ''Tetraptilon,'' but this is rejected by other authors. The leaves of ''Dicroidium'' bifurcate (fork) at their base, which is characteristic of all species. The leaves are h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pachypteris
''Pachypteris'' is a Mesozoic pteridosperm ("seed fern") genus of fossil leaves. It has either been aligned with the peltasperms or the corystosperms. Description ''Pachypteris'' is represented by hypostomatic, bipinnate or unipinnate leaves, with alethopteridian venation (midvein and secondary veins divided once or twice before reaching the pinnule margin), pinnules with entire margins and rounded apices. The stomata are haplocheilic, monocyclic or dicyclic, usually depressed, with the guard cells occurring in the lowermost part of the stoma. Taxonomy The affinities of ''Pachypteris'' lay with '' Cycadopteris'', ''Komlopteris'', ''Dicroidium'' (a typical Corystospermalean foliage) and '' Ptilozamites''. It includes the former denomination ''Thinnfeldia'' Ettingshausen 1852, a junior synonym of ''Pachypteris'', as Doludenko (1971) showed. The genus was detailed by Harris (1964), Doludenko (1974), Schweitzer and Kirchner (1998), Popa (2000), and Gordenko (2007). The genus ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Seed Plant
A seed plant or spermatophyte (; New Latin ''spermat-'' and Greek ' (phytón), plant), also known as a phanerogam (taxon Phanerogamae) or a phaenogam (taxon Phaenogamae), is any plant that produces seeds. It is a category of embryophyte (i.e. land plant) that includes most of the familiar land plants, including the flowering plants and the gymnosperms, but not ferns, mosses, or algae. The term ''phanerogam'' or ''phanerogamae'' is derived from the Greek (), meaning "visible", in contrast to the term "cryptogam" or " cryptogamae" (, and (), 'to marry'). These terms distinguish those plants with hidden sexual organs (cryptogamae) from those with visible ones (phanerogamae). Description The extant spermatophytes form five divisions, the first four of which are classified as gymnosperms, plants that have unenclosed, "naked seeds": * Cycadophyta, the cycads, a subtropical and tropical group of plants, * Ginkgophyta, which includes a single living species of tree in the genus '' ... [...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''), conifers (which were originally suggested to be podocarps, but this was later questioned), as well as Bennettitales. Other plant groups present in the formation include Noeggerathiales, gigantopterid Gigantopterids (Gigantopteridales) is an extinct, possibly polyphyl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triassic
The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is the first and shortest period of the Mesozoic Era and the seventh period of the Phanerozoic Eon. 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sinemurian
In the geologic timescale, the Sinemurian is an age (geology), age and stage (stratigraphy), stage in the Early Jurassic, Early or Lower Jurassic epoch (geology), Epoch or series (stratigraphy), Series. It spans the time between 199.5 ±0.3 annum, Ma and 192.9 ±0.3 Ma (million years ago). The Sinemurian is preceded by the Hettangian and is followed by the Pliensbachian. In Europe the Sinemurian age, together with the Hettangian age, saw the deposition of the lower Lias Group, Lias, in Great Britain known as the Blue Lias. Stratigraphic definitions The Sinemurian Stage was defined and introduced into scientific literature by French palaeontologist Alcide d'Orbigny in 1842. It takes its name from the French town of Semur-en-Auxois, near Dijon. The calcareous soil formed from the Jurassic limestone of the region is in part responsible for the character of the classic Sancerre (wine), Sancerre wines. The base of the Sinemurian Stage is at the first appearance of the ammonite genu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
