| Yavanna chimaerica Temporal range: Aptian ~ | |
|---|---|
Scientific classification  | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Division: | Polypodiophyta |
| Class: | Polypodiopsida |
| Order: | Cyatheales |
| Family: | incertae sedis |
| Genus: | † Yavanna Vera |
| Species: | †Y. chimaerica |
| Binomial name | |
| †Yavanna chimaerica Vera, 2013 | |
Yavanna is an extinct genus of tree ferns known from the Early Cretaceous Cerro Negro Formation of what are now the South Shetland Islands, Antarctica. [1]
Araucaria is a genus of evergreen coniferous trees in the family Araucariaceae once widespread during the Jurassic and Cretaceous periods. There are 20 extant species in New Caledonia, Norfolk Island, eastern Australia, New Guinea, Argentina, Brazil and Chile.
Antarctic flora are a distinct community of vascular plants which evolved millions of years ago on the supercontinent of Gondwana. Presently, species of Antarctica flora reside on several now separated areas of the Southern Hemisphere, including southern South America, southernmost Africa, New Zealand, Australia, and New Caledonia. Joseph Dalton Hooker was the first to notice similarities in the flora and speculated that Antarctica had served as either a source or a transitional point, and that land masses now separated might formerly have been adjacent.
The Antarctic Peninsula, known as O'Higgins Land in Chile and Tierra de San Martín in Argentina, and originally as Graham Land in the United Kingdom and the Palmer Peninsula in the United States, is the northernmost part of mainland Antarctica.
The order Cyatheales, which includes most tree ferns, is a taxonomic order of the fern class, Polypodiopsida. No clear morphological features characterize all of the Cyatheales, but DNA sequence data indicate the order is monophyletic. Some species in the Cyatheales have tree-like growth forms from a vertical rhizome, others have shorter or horizontal expanding rhizomes.
Dicksonia is a genus of tree ferns in the order Cyatheales. It is regarded as related to Cyathea, but is considered to retain more primitive traits, dating back at least to the Jurassic and Cretaceous periods. The fossil record includes stems, pinnules, and spores.
The South Polar region of the Cretaceous comprised the continent of East Gondwana–modern day Australia, Zealandia, and Antarctica–a product of the break-up of Gondwana in the Cretaceous Period. The southern region, during this time, was much warmer than it is today, ranging from perhaps 4–8 °C (39–46 °F) in the latest Cretaceous Maastrichtian in what is now southeastern Australia. This prevented permanent ice sheets from developing and fostered polar forests, which were largely dominated by conifers, cycads, and ferns, and relied on a temperate climate and heavy rainfall. Major fossil-bearing geological formations that record this area are: the Santa Marta and Sobral Formations of Seymour Island off the Antarctic Peninsula; the Snow Hill Island, Lopez de Bertodano, and the Hidden Lake Formations on James Ross Island also off the Antarctic Peninsula; and the Eumeralla and Wonthaggi Formations in Australia.
Dicksoniaceae is a group of tropical, subtropical and warm temperate ferns, treated as a family in the Pteridophyte Phylogeny Group classification of 2016, and counting 30-40 species. Alternatively, the family may be sunk into a very broadly defined family Cyatheaceae sensu lato as the subfamily Dicksonioideae. Most of the genera in the family are terrestrial ferns or have very short trunks compared to tree ferns of the family Cyatheaceae sensu stricto. However, some of the larger species can reach several metres in height. A number of others are epiphytes. They are found mostly in tropical regions in the Southern Hemisphere, as far south as southern New Zealand. Larger tree ferns in the genus Cibotium were formerly included in Dicksoniaceae, but are now segregated as the family Cibotiaceae.
Claytosmunda is a genus of fern. It has only one extant species, Claytosmunda claytoniana, the interrupted fern, native to Eastern Asia, Eastern United States, and Eastern Canada.
Thyrsopteris is a genus of tree fern. It contains a single living species, Thyrsopteris elegans, endemic to the Juan Fernandez Archipelago off the coast of Chile. Thyrsopteris is the only genus in the family Thyrsopteridaceae in the Pteridophyte Phylogeny Group classification of 2016. Alternatively, the genus may be placed in the subfamily Thyrsopteridoideae of a more broadly defined family Cyatheaceae, the family placement used in Plants of the World Online as of November 2019. The oldest records of the genus are the species Thyrsopteris cretacea and Thyrsopteris cyathindusia which were described from the Burmese amber of Myanmar, dating to the Cenomanian of the Cretaceous period, around 99 million years ago. Other fossil species include Thyrsopteris antiqua from the Upper Cretaceous of Chile and Thyrsopteris shenii from the Paleogene of King George Island, Antarctica A thyrsopterid rachis is also known from the Upper Cretaceous of Japan.
Cyathea cranhamii is an extinct species of tree fern. It was described based on permineralised sori from the Early Cretaceous Longarm Formation deposits of Apple Bay on Vancouver Island, British Columbia.
Lophosoria quadripinnata(J.F.Gmel.) C.Chr. is a species of fern that, according to DNA molecular analysis, belongs to the family Dicksoniaceae, where it is placed in the genus Lophosoria. It is found in the Americas spanning from Cuba and Mexico to Chile. In Chile it is present in the area between Talca and Aysén including Juan Fernández Islands. In Argentina it grows only in the humid valleys of western Neuquén and Río Negro Province. Diamondleaf fern is a common name. In Spanish it is known as 'ampe' or palmilla, but one has to remember that there are several species of ferns called "palmillas" that have larger or smaller fronds, and which grow in colder climates. It is a medium-sized plant, growing to about 4–5 feet and even though the rhizome does not grow a trunk, it is clearly related to the other tree ferns due to features that were apparently already present in their common ancestor, like 'pneumathodes', and the rhizome which changed from the dorsiventral symmetry typical of the other ferns, to a radial symmetry typical of tree ferns. Their large and multiple pinnate fronds, with the petiole raised adaxially, and the hairs on the rhizome and lower part of the petioles, also resemble those of tree ferns. To identify the species, use the position and characteristics of the spores found on the fertile fronds. The genus already existed in the Cretaceous Period in southern Gondwana according to fossil remains found in Antarctica. The species is well known as an ornamental plant.
Gondwana was a large landmass, sometimes referred to as a supercontinent. It was formed by the accretion of several cratons, beginning c. 800 to 650Ma with the East African Orogeny, the collision of India and Madagascar with East Africa, and was completed c.600 to 530 Ma with the overlapping Brasiliano and Kuunga orogenies, the collision of South America with Africa, and the addition of Australia and Antarctica, respectively. Eventually, Gondwana became the largest piece of continental crust of the Palaeozoic Era, covering an area of about 100,000,000 km2 (39,000,000 sq mi), about one-fifth of the Earth's surface. It fused with Euramerica during the Carboniferous to form Pangea. It began to separate from northern Pangea (Laurasia) during the Triassic, and started to fragment during the Early Jurassic. The final stages of break-up, involving the separation of Antarctica from South America and Australia, occurred during the Paleogene (from around 66 to 23 million years ago. Gondwana was not considered a supercontinent by the earliest definition, since the landmasses of Baltica, Laurentia, and Siberia were separated from it. To differentiate it from the Indian region of the same name, it is also commonly called Gondwanaland.
Gleichenia is a genus of ferns. Its closest relative is the genus Stromatopteris, restricted to New Caledonia.
Triton Point is a rocky headland at the east end of the high ridge separating Venus Glacier and Neptune Glacier on the east coast of Alexander Island, Antarctica. Lincoln Ellsworth first observed the coast in this vicinity from the air by on 23 November 1935, and it was roughly mapped from photos obtained on that flight by W.L.G. Joerg. The British Graham Land Expedition roughly surveyed Triton Point in 1936 by the Falkland Islands Dependencies Survey more accurately defined it in 1949. The United Kingdom Antarctic Place-Names Committee named it for its association with nearby Neptune Glacier, Triton being one of the satellites of the planet Neptune, the eighth planet of the Solar System.
Matoniaceae is one of the three families of ferns in the Gleicheniales order of the Polypodiopsida class. Fossil records reveal that Matoniaceae ferns were abundant during the Mesozoic era, during which they lived on every continent, including Antarctica, with eight genera and 26 species, with the oldest known specimens being from the Middle Triassic of Antarctica. Today the family is much less abundant, and also less diverse, with only two extant genera and four species, which are limited to portions of southeastern Asia.
Cretaceous polar forests were temperate forests that grew at polar latitudes during the final period of the Mesozoic Era, known as the Cretaceous Period 145–66 Ma. During this period, global average temperature was about 10 °C (18 °F) higher and carbon dioxide (CO2) levels were approximately 1000 parts per million (ppm), 2.5 times the current concentration in Earth's atmosphere. The abundance of atmospheric carbon dioxide had a very significant impact on global climate and Earth's natural systems as its concentration is considered one of the main factors in the development of a pronounced greenhouse Earth during the Cretaceous, with a very low average global temperature gradient. As a consequence, high paleolatitudes in both hemispheres were much warmer than at present. This temperature gradient was partly responsible for the lack of continental ice sheets in polar regions.
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.
Coniopteris is an extinct genus of Mesozoic fern leaves. It was widespread over both hemispheres during the Jurassic and Early Cretaceous, with over 130 species having been described. While traditionally assumed to have been a member of Dicksoniaceae or a close relative of Thyrsopteris, a 2020 cladistic analysis found it to be a stem group of Polypodiales. Most species of Coniopteris probably had a herbaceous habit. Coniopteris laciniata had tufts of leaves sprouting from intervals of a thin, creeping rhizome. The genus is technically a junior synonym of the little used Polystichites, but was conserved by the ICZN in 2013. Some authors suggest a range of Early Jurassic-early Late Cretaceous for the genus, while others suggest a more expansive range spanning from the Middle Triassic to the Eocene.
This list of 2013 in paleobotany records new fossil plant taxa that were described during 2013, as well as other significant discoveries and events related to paleobotany that occurred in the year.
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