Umkomasia

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Umkomasia
Temporal range: Early Triassic–Late Triassic
Umkomasia macleani.jpg
Umkomasia macleanii ovulate structure, Late Triassic, Molteno Formation, Umkomaas, South Africa.
Scientific classification Red Pencil Icon.png
Kingdom: Plantae
Clade: Tracheophytes
Division: Pteridospermatophyta
Order: Peltaspermales
Family: Corystospermaceae
Genus: Umkomasia
Thomas 1933
Species

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. [3] 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. [4]

Contents

Umkomasia macleanii reconstruction with pollen organs (Pteruchus africanus) and leaves (Dicroidium odontopteroides) from the Late Triassic, Molteno Formation of South Africa Umkomasia macleani reconstruction.jpg
Umkomasia macleanii reconstruction with pollen organs ( Pteruchus africanus ) and leaves ( Dicroidium odontopteroides ) from the Late Triassic, Molteno Formation of South Africa

Description

Umkomasia has helmet like cupules around ovules born in complex large branching structures.

Whole plant associations

Reassigned species

See also

Related Research Articles

Paleobotany

Paleobotany, which is also spelled as palaeobotany, is the branch of botany dealing with the recovery and identification of plant remains from geological contexts, and their use for the biological reconstruction of past environments (paleogeography), and the evolutionary history of plants, with a bearing upon the evolution of life in general. A synonym is paleophytology. It is a component of paleontology and paleobiology. The prefix palaeo- means "ancient, old", and is derived from the Greek adjective παλαιός, palaios. Paleobotany includes the study of terrestrial plant fossils, as well as the study of prehistoric marine photoautotrophs, such as photosynthetic algae, seaweeds or kelp. A closely related field is palynology, which is the study of fossilized and extant spores and pollen.

<i>Glossopteris</i> Genus of extinct seed ferns

Glossopteris is the largest and best-known genus of the extinct Permian order of seed ferns known as Glossopteridales. The genus Glossopteris refers only to leaves, within a framework of form genera used in paleobotany. Species of Glossopteris were widespread over the supercontinent of Gondwana during the Permian epoch, where they formed the dominant component of high latitude polar forests. Glossopteris fossils were critical in recognizing former connections between the various fragments of Gondwana: South America, Africa, India, Australia, New Zealand, and Antarctica.

Caytoniales Extinct order of flowering plants

The Caytoniales are an extinct order of seed plants known from fossils collected throughout the Mesozoic Era, specifically in the late Triassic to Maastrichtian period, around 250 to 70 million years ago. They are regarded as seed ferns because they are seed-bearing plants with fern-like leaves. Although at one time considered angiosperms because of their berry-like cupules, that hypothesis was later disproven. Nevertheless, some authorities consider them likely ancestors or close relatives of angiosperms. The origin of angiosperms remains unclear, and they cannot be linked with any known seed plants groups with certainty.

<i>Caytonia</i> Extinct genus of seed ferns

Caytonia is an extinct genus of seed ferns.

<i>Sagenopteris</i> Extinct genus of seed ferns

Sagenopteris is a genus of extinct seed ferns from the Triassic to late Early Cretaceous.

<i>Dicroidium</i> Extinct genus of seed ferns

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.

<i>Lepidopteris</i> Extinct genus of seed ferns

Lepidopteris is a form genus for leaves of Late Permian to Late Triassic Period Pteridospermatophyta, or seed ferns, which lived from around 260 to 200 million years ago in what is now Australia, Antarctica, India, South America, South Africa, Russia and China. Nine species are currently recognized. Lepidopteris was a common and widespread seed fern, which survived the Permian-Triassic extinction event but succumbed to the Triassic-Jurassic extinction event. Lepidopteris callipteroides is especially common between the first two episodes of Permian-Triassic extinction event, and L. ottonis forms a comparable acme zone immediate before the Triassic-Jurassic extinction event. Lepidopteris would persist into the Early Jurassic in Patagonia, represented by the species Lepidopteris scassoi.

This article contains papers in paleobotany that were published in 2016.

<i>Dicroidium odontopteroides</i> Species of ancient plant

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.

<i>Umkomasia macleanii</i> Fossil part of seed fern

Umkomasia macleanii is an ovulate structure of a seed fern (Pteridospermatophyta and the nominate genus of Family Umkomasiaceae. It was first described by Hamshaw Thomas from the Umkomaas locality of South Africa.

<i>Pteruchus africanus</i> Fossil pollen organ of seed fern

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.

<i>Umkomasia feistmantelii</i> Extinct species of plant

Umkomasia feistmantelii is an unusually large species of Umkomasia from the Early Triassic of New South Wales, Australia.

<i>Pteruchus barrealensis</i> Extinct species of flowering plant

Pteruchus barrealensis is an unusually large species of Pteruchus with very elongate polleniferous heads from Early Triassic of Australia and Argentina.

<i>Dicroidium zuberi</i> Species of seed fern

Dicroidium zuberi is a large bipinnate species of the seed fern Dicroidium with a forked rachis. The leaves are affiliated with Umkomasia feistmantellii megasporophylls and Petruchusbarrealensis microsporophylls.

<i>Pteruchus</i> Extinct genus of seed ferns

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.

Peltaspermaceae Extinct family of seed ferns

Peltaspermaceae is a natural family of seed ferns (Pteridospermatophyta) widespread in both northern and southern hemispheres coal measures of Permian and Triassic age. Peltasperms would persist in a relictual distribution in Patagonia during the Early Jurassic.

Corystospermaceae Extinct family of seed ferns

Corystospermaceae is a natural family of seed ferns (Pteridospermatophyta) also called Umkomasiaceae, and first based on fossils collected by Hamshaw Thomas from the Burnera Waterfall locality near the Umkomaas River of South Africa The leaves of Dicroidium were recognized by Alex Du Toit to unite all the countries of the Gondwana supercontinent during the Triassic: Africa, South America, India, and Australia. Subsequently, Dicroidium was found in the Triassic of Antarctica and New Zealand, and also the Permian Umm Irna Formation of Jordan. According to the form generic system of paleobotany, leaves are given separate generic names to ovulate and pollen organs, but the discovery of these reproductive organs in Africa by Thomas, and subsequently throughout Gondwana, strengthened Du Toit's concept of a continuous southern supercontinent. Corystospermaceae were also components of Jurassic and Cretaceous floras, declining in the Cretaceous presumably due to the rise of flowering plants, the last representative of the group, Komlopteris cenozoicus, is known from the Eocene of Tasmania.

<i>Stamnostoma</i> Extinct genus of seed ferns

Stamnostoma is an extinct genus of seed ferns based on cupules with seeds. These are among the earliest known seed plants and of earliest Carboniferous (Tournaisian) age.

<i>Lepidopteris callipteroides</i> Species

Lepidopteris callipteroides is a form species for leaves of Late Permian Pteridospermatophyta, or seed ferns, which lived from around 252 million years ago in what is now Australia, and Madagascar. Lepidopteris callipteroides was an immediate survivor of the largest Permian-Triassic extinction event, migrating southward with the post-apocalyptic greenhouse spike.

This article records new taxa of fossil plants that are scheduled to be described during the year 2020, as well as other significant discoveries and events related to paleobotany that are scheduled to occur in the year 2020.

References

  1. Gongle Shi; Andrew B. Leslie; Patrick S. Herendeen; Fabiany Herrera; Niiden Ichinnorov; Masamichi Takahashi; Patrick Knopf & Peter R. Crane (2016). "Early Cretaceous Umkomasia from Mongolia: implications for homology of corystosperm cupules". New Phytologist. 210 (4): 1418–1429. doi: 10.1111/nph.13871 . PMID   26840646.
  2. However, Rothwell & Stockey (2016) transferred this species to the genus Doylea . See: Gar W. Rothwell; Ruth A. Stockey (2016). "Phylogenetic diversification of Early Cretaceous seed plants: The compound seed cone of Doylea tetrahedrasperma". American Journal of Botany. 103 (5): 923–937. doi: 10.3732/ajb.1600030 . PMID   27208360.
  3. 1 2 Thomas, H.H. (1933). "On some pteridospermous plants from the Mesozoic rocks of South Africa". Philosophical Transactions of the Royal Society B. 222 (483–493): 193–265. doi: 10.1098/rstb.1932.0016 .
  4. Anderson, Heidi M.; Barbacka, Maria K.; Bamford, Marion K.; Holmes, W. B. Keith; Anderson, John M. (2019-01-02). "Umkomasia (megasporophyll): part 1 of a reassessment of Gondwana Triassic plant genera and a reclassification of some previously attributed". Alcheringa: An Australasian Journal of Palaeontology. 43 (1): 43–70. doi:10.1080/03115518.2018.1554748. ISSN   0311-5518. S2CID   134483119.
  5. Retallack G.J. (1977). "Reconstructing Triassic vegetation of southeastern Australia: a new approach to the biostratigraphy of Gondwanaland". Alcheringa. 1: 247–265. doi:10.1080/03115517708527763.
  6. Retallack, G.J. & Dilcher, D.L. (1988). "Reconstructions of selected seed ferns". Missouri Botanical Garden Annals. 75 (3): 1010–1057. doi:10.2307/2399379. JSTOR   2399379.