''Glossopteris'' tymology: from Ancient Greek γλῶσσα (glôssa, " tongue ") + πτερίς (pterís, " fern ")is the largest and best-known

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of the

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

Permian The Permian ( ) is a geologic period and stratigraphic system which spans 47 million years from the end of the Carboniferous Period million years ago (Mya), to the beginning of the Triassic Period 251.9 Mya. It is the last period of the Paleo ...

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...

of seed ferns known as Glossopteridales (also known as Arberiales, Ottokariales, or Dictyopteridiales). The genus ''Glossopteris'' refers only to leaves, within a framework of form genera used in

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 (paleogeog ...

. (For likely reproductive organs see Glossopteridaceae.) Species of ''Glossopteris'' were the dominant trees of the middle- to high-latitude lowland vegetation across the supercontinent

Gondwana Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final sta ...

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.

History

The Glossopteridales arose in the Southern Hemisphere around the beginning of the

Period (), but became extinct during the end-Permian (Changhsingian) mass extinction. The putative persistence of ''Glossopteris'' into younger strata is commonly invoked on the basis of the distribution of dispersed taeniate bisaccate pollen. However, this category of pollen is known to have been produced by various seed plants, and Triassic examples, in the absence of convincing co-preserved ''Glossopteris'' leaves, probably belonged to non-glossopterid groups, such as voltzialean conifers. The distribution of ''Glossopteris'' across several, now detached, landmasses led Eduard Suess, amongst others, to propose that the southern continents were once amalgamated into a single

supercontinent In geology, a supercontinent is the assembly of most or all of Earth's continental blocks or cratons to form a single large landmass. However, some geologists use a different definition, "a grouping of formerly dispersed continents", which leav ...

— Pangea. These plants went on to become the dominant elements of the southern flora through the rest of the Permian but disappeared in almost all places at the end of the Permian (). The only potential

Triassic The Triassic ( ) is a geologic period and system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.36 Mya. The Triassic is the first and shortest per ...

records are ''Glossopteris'' leaves exposed in the banks of the Gopad River near Nidpur, India, but even these records are stratigraphically ambiguous owing to faulting and complex juxtapositioning of Permian and Triassic

strata In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as e ...

at Nidpur. Moreover, even if some ''Glossopteris'' leaves do persist above the end-Permian extinction horizon, this level pre-dates the Permian-Triassic boundary proper in continental settings of Gondwana by several hundred thousand years and there are no convincing examples of ''Glossopteris'' in confidently dated Triassic strata. Although most modern palaeobotany textbooks cite the continuation of glossopterids into later parts of the Triassic and, in some cases into the

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

, these ranges are erroneous and are based on misidentification of morphologically similar leaves such as '' Gontriglossa'', ''

Sagenopteris ''Sagenopteris'' is a genus of extinct seed ferns from the Triassic to late Early Cretaceous.Mexiglossa''. Glossopterids were, thus, one of the major casualties of the end-Permian mass

extinction event An extinction event (also known as a mass extinction or biotic crisis) is a widespread and rapid decrease in the biodiversity on Earth. Such an event is identified by a sharp change in the diversity and abundance of multicellular organisms. I ...

More than 70

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

species of this genus have been recognized in

India India, officially the Republic of India (Hindi: ), is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area, the List of countries and dependencies by population, second-most populous ...

alone, with additional species from

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the sou ...

Australia Australia, officially the Commonwealth of Australia, is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. With an area of , Australia is the largest country by ...

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Afric ...

and

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest cont ...

. Essentially, ''Glossopteris'' was restricted to the middle- and high-latitude parts of Gondwana during the Permian and was an important contributor to the vast Permian coal deposits of the Southern Hemisphere continents. Most northern parts of South America and Africa lack ''Glossopteris'' and its associated organs. However, in recent years a few disparate localities in Morocco, Oman, Anatolia, the western part of the island of New Guinea, Thailand and Laos have yielded fossils that are of possible glossopterid affinity. These peri-gondwanan records commonly occur together with Cathaysian or Euramerican plant species—the assemblages representing a zone of mixing between the strongly provincial floras of the Permian. Apart from those in India and the peri-gondwanan localities, a few other fossils from the Northern Hemisphere have been assigned to this group, but these are not identified with great certainty. For example, specimens assigned to ''Glossopteris'' from the far east of Russia in the 1960s are more likely to be misdentifications of other

gymnosperms The gymnosperms ( lit. revealed seeds) are a group of seed-producing plants that includes conifers, cycads, '' Ginkgo'', and gnetophytes, forming the clade Gymnospermae. The term ''gymnosperm'' comes from the composite word in el, γυμν� ...

such as '' Pursongia''. Confident assignment of fossil leaves to ''Glossopteris'' normally requires their co-preservation with the distinctive segmented roots of this group (called '' Vertebraria'') or with the distinctive fertile organs. In 2018, ''Glossopteris'' leaves were reported from mid-Permian ( Roadian – early Wordian) deposits in Mongolia, then located at high latitudes in the Northern Hemisphere, but these fossils were not found in association with other typical glossopterid organs, such as chambered roots or reproductive structures, so the phylogenetic affinities of these leaves remain uncertain.

Taxonomy

Long considered a

fern A fern (Polypodiopsida or Polypodiophyta ) is a member of a group of vascular plants (plants with xylem and phloem) that reproduce via spores and have neither seeds nor flowers. The polypodiophytes include all living pteridophytes exce ...

after its discovery in the 1820s, it was later assigned to the

gymnosperm The gymnosperms ( lit. revealed seeds) are a group of seed-producing plants that includes conifers, cycads, '' Ginkgo'', and gnetophytes, forming the clade Gymnospermae. The term ''gymnosperm'' comes from the composite word in el, γυμν ...

s. The genus is placed in the division Pteridospermatophyta. In reality, many of the plant groups included within this division are only distantly related to one another. Glossopterids' relationships with other groups remain obscure. Most recent phylogenetic analyses favour placement of glossopterids as sister to a large group including Corystospermales,

Caytoniales The Caytoniales (Figs. 1-2) are an extinct order of seed plants known from fossils collected throughout the Mesozoic Era, around . They are regarded as seed ferns because they are seed-bearing plants with fern-like leaves. Although at one time c ...

, Bennettitales, Pentoxylales, Gnetales (in some analyses), and

angiosperm Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants ...

s. A few analyses favour alternative links with

Ginkgoales Ginkgoales are a gymnosperm order containing only one extant species: ''Ginkgo biloba'', the ginkgo tree. It is monotypic, (the only taxon) within the class Ginkgoopsida, which itself is monotypic within the division Ginkgophyta . The order incl ...

, Cordaitales and Pinales. ''Glossopteris'' should strictly be used to refer to the distinctive

spathulate This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary o ...

fossil leaves with reticulate venation, however, the term has also been used to refer to the parent plant as a whole. The name comes from Ancient Greek ( 'tongue'), because the leaves were tongue-shaped, and ( 'fern, feathery').

Description

''Glossopteris'' was a woody, seed-bearing shrub or tree, some apparently reaching 30 meters tall. They had a softwood interior that resembles conifers of the family Araucariaceae. Seeds were borne on one side of variably branched or fused structures, and microsporangia containing

pollen Pollen is a powdery substance produced by seed plants. It consists of pollen grains (highly reduced microgametophytes), which produce male gametes (sperm cells). Pollen grains have a hard coat made of sporopollenin that protects the gametop ...

were borne in clusters at the tips of slender filaments. Both the seed- and pollen-bearing organs were partially fused (adnate) to the leaves, or, in some cases, possibly positioned in the

axils A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...

of leaves. The homologies of the flattened seed-bearing structures have remained particularly controversial with some arguing that the fertile organs represent megasporophylls (fertile leaves) whereas others have interpreted the structures as flattened, seed-bearing, axillary axes (cladodes). It is unclear whether glossopterids were

monoecious Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system alongside gynomonoecy, andromonoecy and trimonoecy. Monoecy is ...

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproducti ...

, the fact that only pollen organ bearing leaves and not ovules were found in some layers suggest that at least some species were the latter.

Paleoecology

They are interpreted to have grown in very wet soil conditions, similar to the modern

Bald Cypress ''Taxodium distichum'' (bald cypress, swamp cypress; french: cyprès chauve; ''cipre'' in Louisiana) is a deciduous conifer in the family Cupressaceae. It is native to the southeastern United States. Hardy and tough, this tree adapts to a wide ...

. The leaves ranged from about 2 cm to over 30 cm in length. The profile of glossopterid trees is largely speculative as complete trees have not been preserved. However, based on analogies with modern high-latitude plants ''Glossopteris'' trees probably tapered upwards like a

Christmas tree A Christmas tree is a decorated tree, usually an evergreen conifer, such as a spruce, pine or fir, or an artificial tree of similar appearance, associated with the celebration of Christmas. The custom was further developed in early modern ...

and were relatively widely spaced to take advantage of the low-angle sunlight at high latitudes, instead of needles, they had large, broad lance- or tongue-shaped leaves commonly with well differentiated palisade and spongy mesophyll layers. Glossopteris cross section

''Glossopteris'' trees are assumed to be have been

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, ...

, as fossil leaves are commonly found as dense accumulations representing autumnal leaf banks. The broad fossilized growth rings in many ''Glossopteris'' woods reveal that the plants experienced strong growth spurts each spring-summer but underwent the abrupt cessation of growth before each following winter. The idea that all ''Glossopteris'' species are deciduous has been challenged, with an isotopic study finding that Antarctic ''Glossopteris'' forests were mixed evergreen-deciduous. ''Glossopteris'' leaves are morphologically simple so there are few characters that can be used to differentiate species. Consequently, many past researchers have considered the Permian ''Glossopteris'' flora to be rather homogeneous with the same species distributed throughout the Southern Hemisphere. However, more recent studies of the more morphologically diverse fertile organs have shown that taxa had more restricted regional distributions and several intra-gondwanan floristic provinces are recognizable. Seeds, much too large to be wind-borne, could not have blown across thousands of miles of open sea, nor is it likely they have floated across vast oceans. Observations such as these led the

Austria Austria, , bar, Östareich officially the Republic of Austria, is a country in the southern part of Central Europe, lying in the Eastern Alps. It is a federation of nine states, one of which is the capital, Vienna, the most populous ...

n geologist Eduard Suess to deduce that there had once been a land bridge between these areas. He named this large land mass Gondwanaland (named after the district in India where the plant ''Glossopteris'' was found). These same observations would also lend support to Alfred Wegener's

Continental drift Continental drift is the hypothesis that the Earth's continents have moved over geologic time relative to each other, thus appearing to have "drifted" across the ocean bed. The idea of continental drift has been subsumed into the science of pl ...

theory. The first Antarctic specimens of ''Glossopteris'' were discovered by members of Robert Scott's doomed ''Terra Nova'' expedition. The expedition members abandoned much of their gear in an effort to reduce their load, but kept 35 pounds of ''Glossopteris'' fossils; these were found alongside their bodies.

Outcrops in Brazil

The first investigation of a ''Glossopteris'' flora associated with coal seams within a paleogeographic and palaeoclimatic context, in the Paraná Basin, southern

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

, was that by geologist Israel Charles White in 1908. This allowed correlation between Gondwanan coal deposits in southern Brazil and those documented in

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring coun ...

and

, and showed that this flora flourished in latitudes near the south pole. In

Rio Grande do Sul Rio Grande do Sul (, , ; "Great River of the South") is a state in the southern region of Brazil. It is the fifth-most-populous state and the ninth largest by area. Located in the southernmost part of the country, Rio Grande do Sul is border ...

, ''Glossopteris'' leaves were found in paleorrota at ''Mina Faxinal'', in Arroio dos Ratos at ''Mina Morro do Papaléo'' in Mariana Pimentel and ''Quitéria'' in

Pantano Grande Pantano Grande is a municipality in the state of Rio Grande do Sul, Brazil. See also *List of municipalities in Rio Grande do Sul This is a list of the municipalities in the state of Rio Grande do Sul (RS), located in the South Region of Brazi ...

. Various species were recovered from the Rio Bonito Formation at these sites including ''G. angustifolia, G. brasiliensis, G. browniana, G. communis, G. indica and G. occidentalis''.

References

Sources

* Brongniart, A. 1828. Prodrome d’une histoire des végétaux fossiles. Paris. 223 pp. * Brongniart, A. 1832. Histoire des végétaux fossiles ou recherches botaniques et géologiques sur les végétaux renfermés dans les diverses couches du globe. G. Dufour and E. D’Ocagne, Paris 1: 265–288. * Anderson, H.M. & Anderson, J.M. 1985. The Palaeoflora of Southern Africa: Prodromus of Southern African Megafloras, Devonian to Lower Cretaceous. A.A. Balkema, Rotterdam. 416 pp. * Chandra, S. & Surange, K.R. 1979. Revision of the Indian species of Glossopteris. Monograph 2. Birbal Sahni Institute of Palaeobotany, Lucknow. 301 pp. * Davis, Paul and Kenrick, Paul. 2004. Fossil Plants. Smithsonian Books (in association with the Natural History Museum of London), Washington, D.C. * Gould, R. E. and Delevoryas, T., 1977. The biology of Glossopteris: evidence from petrified seed-bearing and pollen-bearing organs. Alcheringa, 1: 387–399. * Pant DD 1977 The plant of Glossopteris. J Indian Bot Soc 56: 1-23. * Pant, D.D. & Gupta, K.L. 1971. Cuticular structure of some Indian Lower Gondwana species of Glossopteris Brongniart. Part 2. - Palaeontographica, 132B: 130–152. * Pant, D.D. & Nautiyal, D.D. 1987. Diphyllopteris verticellata Srivastava, the probable seedling of Glossopteris from the Paleozoic of India. - Rev. Palaeobot. Palynol., 51: 31–36. * Pant, D.D. & Pant, R. 1987. Some Glossopteris leaves from Indian Triassic beds. - Palaeontographica, 205B: 165–178. * Pant, D.D. & Singh, K.B. 1971. Cuticular structure of some Indian Lower Gondwana species of Glossopteris Brongniart. Part 3. - Palaeontographica, 135B: 1-40. * Pigg, K. B. 1990. Anatomically preserved Glossopteris foliage from the central Transantarctic Mountains. Rev. Palaeobot. Palynol. 66: 105–127. * * Plumstead, E.P. (1969), Three thousand million years of plant life in Africa. Alex L. du Toit Memorial Lecture no. 11. Trans. Geol. Soc. S. Afr. 72 (annex.): 1-72. * Taylor, E.L, Taylor, T.N. & Collinson, J.W. 1989. Depositional setting and palaeobotany of Permian and Triassic permineralized peat from the central Transantarctic Mountains, Antarctica. - Internat. J. Coal Geol., 12: 657–679.

External links

Glossopteris
{{Taxonbar, from=Q1801472 Prehistoric life of Oceania Pteridospermatophyta Permian plants Cisuralian first appearances Cisuralian genus extinctions Prehistoric life of Africa Prehistoric life of Asia Prehistoric life of South America Prehistoric plant genera Prehistoric plants of South America Prehistory of Oceania Flora of Antarctica Fossils of Antarctica Fossils of Argentina Fossils of Australia Fossils of Bolivia Fossils of Botswana Fossils of Brazil Fossils of China Fossils of the Democratic Republic of the Congo Fossils of India Fossils of Madagascar Fossils of Mozambique Fossils of New Zealand Fossils of Oman Fossils of Pakistan Fossils of Papua New Guinea Fossils of Russia Fossils of South Africa Fossils of Tanzania Fossils of Turkey Fossils of Uganda Fossils of Uruguay Fossils of Zambia Fossils of Zimbabwe Paraná Basin Permian Antarctica Permian life of Australia Permian Brazil Fossil taxa described in 1828