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Corystospermaceae
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 y ... [...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] |
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] |
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] |
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] |
Seed Ferns
Pteridospermatophyta, also called pteridosperms or seed ferns, are a polyphyletic grouping of extinct Spermatophyte, seed-producing plants. The earliest fossil evidence for plants of this type are the Lyginopteridales, lyginopterids of late Devonian age. They flourished particularly during the Carboniferous and Permian periods. Pteridosperms declined during the Mesozoic Era and had mostly disappeared by the end of the Cretaceous Period, though ''Komlopteris'' seem to have survived into Eocene times, based on fossil finds in Tasmania. With regard to the enduring utility of this division (botany), division, many palaeobotanists still use the pteridosperm grouping in an informal sense to refer to the seed plants that are not angiosperms, coniferoids (conifers or cordaites), Ginkgoaceae, ginkgophytes (ginkgos or czekanowskiales), cycadophytes (cycads or Bennettitales, bennettites), or gnetophytes. This is particularly useful for extinct seed plant groups whose systematic relationship ... [...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
''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 seed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Jurassic
The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) 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 174.7 ±0.8 Ma. Certain rocks of marine origin of this age in Europe are called "Lias Group, Lias" and that name was used for the period, as well, in 19th-century geology. In southern Germany rocks of this age are called Black Jurassic. Origin of the name Lias There are two possible origins for the name Lias: the first reason is it was taken by a geologist from an England, English quarryman's dialect pronunciation of the word "layers"; secondly, sloops from north Cornwall, Cornish ports such as Bude would sail across the Bristol Channel to the Vale of Glamorgan to load up with rock from coastal limestone quarries (lias and Carbonif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
