Dicroidium

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Dicroidium
Temporal range: Late PermianSinemurian
Dicroidium odontopteroides.jpg
Dicroidium odontopteroides fossil leaf, Late Triassic Molteno Formation near Birds River South Africa.
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Plantae
Order: Corystospermales
Family: Corystospermaceae
Genus: Dicroidium
Gothan (1912)
Species
  • Dicroidium crassinervis Australia, Antarctica, South Africa
  • Dicroidium coriaceum, Australia, Antarctica, South Africa
  • Dicroidium dubium Australia, Antarctica, South Africa
  • Dicroidium odontopteroides , Australia, New Zealand, Antarctica, India, South Africa, Argentina, Brazil [1]
  • Dicroidium stelznerianum, Australia, New Zealand, Antarctica, South Africa, Argentina [2]
Synonyms
  • Johnstonia Walkom
  • Harringtonia Frenguelli
  • Dicroidiopsis Frenguelli
  • Diplasiophyllum Frenguelli
  • Zuberia Frenguelli
  • Xylopteris Frenguelli
  • Tetraptilon Frenguelli
  • Hoegia Townrow
  • Jordaniopteris Anderson

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 were widely distributed and dominant over Gondwana during the Triassic ( 252 to 201 million years ago). Their fossils are known from South Africa, the Arabian Peninsula, Australia, New Zealand, South America, Madagascar, the Indian subcontinent and Antarctica.

Description

Dicroidium zuberi Dicroidium zuberi leaf.jpg
Dicroidium zuberi

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. [4] The leaves of Dicroidium bifurcate (fork) at their base, which is characteristic of all species. The leaves are highly variable in size and morphology, ranging from simple to tripinnate, with the individual leaflets having varying morphologies, including dissected , lobed, needle-like and entire. [5] Some leaf specimens have more than one type of leaflet morphology, which may have been the result of hybridisation between different species. [4] The venation of the leaves is also highly variable, encompassing taeniopteroid, odontopteroid, alethopteroid and simple morphologies. [5]

Whole plant

Reconstruction of the whole plant of Dicroidium odontopteroides , including Umkomasia macleanii (L-P) and Pteruchus africanus (H-K) Umkomasia macleani reconstruction.jpg
Reconstruction of the whole plant of Dicroidium odontopteroides , including Umkomasia macleanii (L-P) and Pteruchus africanus (H-K)

Dicroidium plants grew as medium-large sized trees, [5] with some preserved trunk sections 10 metres (33 ft) tall and over 50 centimetres (20 in) wide, [4] with the wood assigned to the genera Kykloxylon and Rhexoxylon. The ovulate reproductive structures are usually assigned to the genus Umkomasia, while the pollen-producing organs are assigned to the genus Pteruchus, with pollen attributable to the genus Falcisporites. These structures are almost never found in organic connection, and their placement as part of the same plant primarily relies on their repeated co-occurrence with each other, and the similarities in the morphology of their cuticles. [6] The leaves grew on short protuberances attached to the stem in a similar way to living Ginkgo biloba . [7] [8] The leaves of Dicroidium are suggested to have been deciduous, and shed along with the reproductive organs during the winter. The seeds and pollen are suggested to have been wind dispersed. [4]

Possible whole plant associations include:

Evolution

The earliest Dicroidium species are known from the Late Permian aged Umm Irna Formation of Jordan, which inhabited equatorial humid tropical environments, [6] as well as equivalently aged more southerly subtropical deposits on Indian subcontinent. [11] Following the end-Permian mass extinction, Dicroidium expanded its range southwards across Gondwana, including South Africa, Antarctica, Australia, New Zealand, India and South America. [6] Later Triassic Dicroidum-bearing plants were dominant large canopy forming trees in temperate wetland and forested habitats at mid-high latitudes, extending to the South Pole. [4] [5] [6] Dicroidium-dominanted ecosystems in Gondwana collapsed during the end-Triassic mass extinction, with Dicroidium surviving in parts of East Antarctica into the Early Jurassic (Sinemurian). [5]

Related Research Articles

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

Glossopteris is the largest and best-known genus of the extinct Permian order of seed plants known as Glossopteridales. The genus Glossopteris refers only to leaves, within a framework of form genera used in paleobotany. Species of Glossopteris were the dominant trees of the middle to high-latitude lowland vegetation across the supercontinent Gondwana during the Permian Period. Glossopteris fossils were critical in recognizing former connections between the various fragments of Gondwana: South America, Africa, India, Australia, New Zealand, and Antarctica.

<span class="mw-page-title-main">Bennettitales</span> Extinct order of seed plants

Bennettitales is an extinct order of seed plants that first appeared in the Permian period and became extinct in most areas toward the end of the Cretaceous. Bennettitales were amongst the most common seed plants of the Mesozoic, and had morphologies including shrub and cycad-like forms. The foliage of bennettitaleans is superficially nearly indistinguishable from that of cycads, but they are distinguished from cycads by their more complex flower-like reproductive organs, at least some of which were likely pollinated by insects.

<span class="mw-page-title-main">Hanson Formation</span> Geological formation in Ross Dependency, Antarctica

The Hanson Formation is a geologic formation on Mount Kirkpatrick and north Victoria Land, Antarctica. It is one of the two major dinosaur-bearing rock groups found on Antarctica to date; the other is the Snow Hill Island Formation and related formations from the Late Cretaceous of the Antarctic Peninsula. The formation has yielded some Mesozoic specimens, but most of it is as yet unexcavated. Part of the Victoria Group of the Transantarctic Mountains, it lies below the Prebble Formation and above the Falla Formation. The formation includes material from volcanic activity linked to the Karoo-Ferar eruptions of the Lower Jurassic. The climate of the zone was similar to that of modern southern Chile, humid, with a temperature interval of 17–18 degrees. The Hanson Formation is correlated with the Section Peak Formation of the Eisenhower Range and Deep Freeze Range, as well as volcanic deposits on the Convoy Range and Ricker Hills of southern Victoria Land. Recent work has successfully correlated the Upper Section Peak Formation, as well unnamed deposits in Convoy Range and Ricker Hills with the Lower Hanson, all likely of Sinemurian age and connected by layers of silicic ash, while the upper section has been found to be Pliensbachian, and correlated with a greater volcanic pulse, marked by massive ash inputs.

<span class="mw-page-title-main">Keith Holmes (palaeobotanist)</span> Australian paleobotanist

William Brian Keith Holmes is an Australian palaeobotanist, best known for his work "Fructifications of Glossopteris" (1974), published in the Proceedings of the Linnean Society of New South Wales. Despite having received no formal training in palaeontology, he has become an important contributor in the field and has described some 80 new species, mostly from 2 quarries at Nymboida in northern New South Wales, and situated on the Triassic.

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

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

<span class="mw-page-title-main">Gregory Retallack</span> American paleontologist

Gregory John Retallack is an Australian paleontologist, geologist, and author who specializes in the study of fossil soils (paleopedology). His research has examined the fossil record of soils though major events in Earth history, extending back some 4.6 billion years. He has written two textbooks on paleopedology.

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

Lepidopteris is a form genus for leaves of Peltaspermaceae, an extinct family of seed plants, which lived from around 260 to 190 million years ago, from the Late Permian to Early Jurassic. Fossils of the genus have been found across both hemispheres. Nine species are currently recognized.Lepidopteris was a common and widespread seed fern, which survived the Permian-Triassic extinction event but was largely wiped out by 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.

<span class="mw-page-title-main">Peltaspermales</span> Extinct order of seed ferns

The Peltaspermales are an extinct order of seed plants, often considered "seed ferns". They span from the Late Carboniferous to the Early Jurassic. It includes at least one valid family, Peltaspermaceae, which spans from the Permian to Early Jurassic, which is typified by a group of plants with Lepidopteris leaves, Antevsia pollen-organs, and Peltaspermum ovulate organs, though the family now also includes other genera like Peltaspermopsis, Meyenopteris and Scytophyllum. Along with these, two informal groups of uncertain taxonomic affinities exist, each centered around a specific genus ; Supaia and Comia, known from the Early Permian of the Northern Hemisphere, especially of North America. Both the "Comioids" and the "Supaioids" are associated with the peltaspermacean ovulate organ Autunia. The Late Triassic-Middle Jurassic genus Pachydermophyllum may also have affinities to the peltasperms.

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

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.

<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>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.

<span class="mw-page-title-main">Dictyopteridiaceae</span> Extinct family of seed ferns

Dictyopteridiaceae are an extinct family of glossopterid plants known from the Permian period. It generally refers to reproductive organs, which are associated with Glossopteris leaves.

<span class="mw-page-title-main">Corystospermaceae</span> Extinct family of seed ferns

Corystosperms are a group of extinct seed plants belonging to the family Corystospermaceae 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 old, over 10 million years after the Cretaceous–Paleogene extinction event.

<i>Dictyopteridium</i> Extinct genus of plants

Dictyopteridium is an extinct genus of plants belonging to Glossopteridaceae, but the name is used only for compression fossils of elongate multiovulate reproductive structures adnate to Glossopteris leaves. Permineralized remains identical to Dictyopteridium have been referred to the organ genus Homevaleia

<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.

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 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, conifers, as well as Bennettitales. Other plant groups present in the formation include Noeggerathiales, gigantopterids, lyginopterids and possible ginkgophytes.

<i>Komlopteris</i> Extinct genus of seed fern

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.

References

  1. THE TRIASSIC TAPHOFLORA FROM PARANA BASIN, SOUTHERN BRAZIL
  2. Retallack G.J. (1985). "Triassic fossil plant fragments from marine rocks of the Murihiku Supergroup, New Zealand". Journal of the Royal Society of New Zealand. 15: 1–26. doi: 10.1080/03036758.1985.10421741 .
  3. Passo das Tropas, Santa Maria, RS Marco bioestratigráfico triássico na evolução paleoflorística do Gondwana na Bacia do Paraná.
  4. 1 2 3 4 5 Mays, Chris; McLoughlin, Stephen (2020-02-25). "Caught between two mass extinctions: The rise and fall of Dicroidium". Deposits Mag. Retrieved 2023-09-23.
  5. 1 2 3 4 5 Bomfleur, Benjamin; Blomenkemper, Patrick; Kerp, Hans; McLoughlin, Stephen (2018), "Polar Regions of the Mesozoic–Paleogene Greenhouse World as Refugia for Relict Plant Groups", Transformative Paleobotany, Elsevier, pp. 593–611, doi:10.1016/b978-0-12-813012-4.00024-3, ISBN   978-0-12-813012-4 , retrieved 2020-11-12
  6. 1 2 3 4 Blomenkemper, Patrick; Kerp, Hans; Abu Hamad, Abdalla; Bomfleur, Benjamin (July 2020). "Contributions towards whole-plant reconstructions of Dicroidium plants (Umkomasiaceae) from the Permian of Jordan". Review of Palaeobotany and Palynology. 278: 104210. doi:10.1016/j.revpalbo.2020.104210.
  7. Anderson, H.M., Holmes, W.B.K. & Fitness, F.A., 2008. Stems with attached Dicroidium leaves from the Ipswich Coal Measures, Queensland, Australia. Memoirs of the Queensland Museum52, 1–12.
  8. Anderson, Heidi M.; Barbacka, Maria; Bamford, Marion K.; Holmes, W. B. Keith; Anderson, John M. (2020-01-02). "Dicroidium (foliage) and affiliated wood Part 3 of a reassessment of Gondwana Triassic plant genera and a reclassification of some previously attributed". Alcheringa: An Australasian Journal of Palaeontology. 44 (1): 64–92. doi:10.1080/03115518.2019.1622779. ISSN   0311-5518.
  9. 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.
  10. 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.
  11. Schneebeli-Hermann, Elke; Kürschner, Wolfram M.; Kerp, Hans; Bomfleur, Benjamin; Hochuli, Peter A.; Bucher, Hugo; Ware, David; Roohi, Ghazala (April 2015). "Vegetation history across the Permian–Triassic boundary in Pakistan (Amb section, Salt Range)". Gondwana Research. 27 (3): 911–924. doi:10.1016/j.gr.2013.11.007.