Gigantopterid
Encyclopedia
Gigantopterids is the name given to fossil
s of a group of plants existing in the Late Permian, some . Gigantopterids were among the most advanced land plants of the Paleozoic
and disappeared soon after the massive Permian–Triassic extinction event . Though some lineages of these plants managed to persist initially, they either disappeared entirely or adapted radically, evolving
into undetermined descendants, as surviving life prospered again in much-altered ecosystems. One hypothesis proposes that at least some "gigantopterids" became the ancestors of angiosperms and/or Bennettitales
and/or Caytoniales
.
Gigantopterid fossils were documented as early as 1883, but only investigated more thoroughly in the early 20th century. Some of their most significant evidence has been initially found in Texas
, but they may have been present worldwide: another key region for gigantopterid fossils is in China
, and the consolidation of all major continent
s into Pangea would have allowed for easy global dispersal. They were among the most striking and important plants of the Cathaysian flora of Sino
-Malaya
, also called Gigantopteris flora to reflect this.
s, but are not known to have flowered themselves. Gigantopterid plants had simple, bilaterally symmetrical leaf structures, woody stems and spines. They grew new parts by producing shoots, like flowering plants. Judging from the fossil remains, they were probably robust plants with frond
s that resembled fern
fronds when young. When mature they were more like flowering plant leaves
with reticulate venation arranged in a frond. Gigantopteris nicotianaefolia for example is named thus because each of its leaflet
s resembles a tobacco
leaf in shape.
They grew at least over 20 cm (around 10 in), probably over 50 cm (20 in) tall, depending on whether it grew as a scrambling vine (the initial assumption) or erect (nowadays considered more likely). Some were apparently amphibious
, while others thrived in rather arid
habitat
.
The vascular tissue
contains vessel element
s and in at least some taxa resembles that of the Gnetophyta
. They had a cuticula
similar to that of other seed plants. Some male sporangia (Gigantotheca) and seed
s (Gigantonomia, Cornucarpus) have been tentatively referred to this group. While the sporangia are certainly not flowers, they differ from other sporangia of Permian plants.
Chemical analysis of fossil
remains indicates that gigantopterids produced oleanane
s, chemical compounds otherwise known to be used by flowering plants, for which they function as a suppressant of insect pests. They are apparently also found in certain modern ferns however.
. Plant life from their era is very difficult to document and organize. They have been variously allied with the "seed ferns" (another paraphyletic group of early seed plants) Peltaspermales and Callistophytales
, Gnetum
, and the Magnoliophyta. All that can be said at present is that they were spermatophyte
s. It is also highly unlikely that they were close relatives of gymnosperm
s, cycads or ginkgos, because these lineages were already established and distinct in the Late Permian.
Vegetative leaves of Emplectopteris were at one time included in this group. However, they had ovules attached to the underside of the fronds and are now placed in their own family (Emplectopteridaceae
) within the Callistophytales
.
Some prefer to refer to the presumed "core" taxa of this group as Gigantonomiales. However, many experts remain skeptical of the new name, because they consider such a move premature until more is known about the interrelationships of the genera
of "gigantopterids" and the relationships of these to other plants.
Several genera have been named. Those then known were assigned to a family
Gigantopteridaceae and numerous subfamilies by Gen-ichi Koidzumi
. It appears as if at least some of his divisions ought to prove useful when a more definite phylogenetic, systematic
and taxonomic arrangement for this group is eventually found. On the other hand, the Gigantopteridaceae would with near certainty have to be more narrowly circumscribed even if the Gigantopteridales are by and large verified as a clade
; they might even become limited to the two or so genera now placed in the Gigantopteridieae.
Gigantopteridieae (including Cardioglossieae)
Gothanopteridieae - may be synonym of Cathaysiopteridieae/Palaeogoniopteridieae
Palaeogoniopteridieae
Unresolved
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s of a group of plants existing in the Late Permian, some . Gigantopterids were among the most advanced land plants of the Paleozoic
Paleozoic
The Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...
and disappeared soon after the massive Permian–Triassic extinction event . Though some lineages of these plants managed to persist initially, they either disappeared entirely or adapted radically, evolving
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
into undetermined descendants, as surviving life prospered again in much-altered ecosystems. One hypothesis proposes that at least some "gigantopterids" became the ancestors of angiosperms and/or Bennettitales
Bennettitales
Bennettitales is an extinct order of seed plants that first appeared in the Triassic period and became extinct toward the end of the Cretaceous...
and/or Caytoniales
Caytoniales
The Caytoniales is an extinct order of seed plants whose presence is recorded in fossils collected throughout the Mesozoic Era . The plants are part of the group called seed ferns because they are seed-bearing plants with fern-like leaves....
.
Gigantopterid fossils were documented as early as 1883, but only investigated more thoroughly in the early 20th century. Some of their most significant evidence has been initially found in Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
, but they may have been present worldwide: another key region for gigantopterid fossils is in China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
, and the consolidation of all major continent
Continent
A continent is one of several very large landmasses on Earth. They are generally identified by convention rather than any strict criteria, with seven regions commonly regarded as continents—they are : Asia, Africa, North America, South America, Antarctica, Europe, and Australia.Plate tectonics is...
s into Pangea would have allowed for easy global dispersal. They were among the most striking and important plants of the Cathaysian flora of Sino
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...
-Malaya
Malay Peninsula
The Malay Peninsula or Thai-Malay Peninsula is a peninsula in Southeast Asia. The land mass runs approximately north-south and, at its terminus, is the southern-most point of the Asian mainland...
, also called Gigantopteris flora to reflect this.
Description
They bore many of the traits of flowering plantFlowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...
s, but are not known to have flowered themselves. Gigantopterid plants had simple, bilaterally symmetrical leaf structures, woody stems and spines. They grew new parts by producing shoots, like flowering plants. Judging from the fossil remains, they were probably robust plants with frond
Frond
The term frond refers to a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group...
s that resembled fern
Fern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...
fronds when young. When mature they were more like flowering plant leaves
Leaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
with reticulate venation arranged in a frond. Gigantopteris nicotianaefolia for example is named thus because each of its leaflet
Leaflet
A leaflet in botany is a part of a compound leaf. A leaflet may resemble an entire leaf, but it is not borne on a stem as a leaf is, but rather on a vein of the whole leaf. Compound leaves are common in many plant families...
s resembles a tobacco
Nicotiana
Nicotiana is a genus of herbs and shrubs of the nightshade family indigenous to North and South America, Australia, south west Africa and the South Pacific. Various Nicotiana species, commonly referred to as tobacco plants, are cultivated and grown to produce tobacco. Of all Nicotiana species,...
leaf in shape.
They grew at least over 20 cm (around 10 in), probably over 50 cm (20 in) tall, depending on whether it grew as a scrambling vine (the initial assumption) or erect (nowadays considered more likely). Some were apparently amphibious
Amphibious
Amphibious means able to use either land or water. In particular it may refer to:*Amphibious warfare, warfare carried out on both land and water*Amphibians, vertebrate animals of the Class Amphibia...
, while others thrived in rather arid
Arid
A region is said to be arid when it is characterized by a severe lack of available water, to the extent of hindering or even preventing the growth and development of plant and animal life...
habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
.
The vascular tissue
Vascular tissue
Vascular tissue is a complex conducting tissue, formed of more than one cell type, found in vascular plants. The primary components of vascular tissue are the xylem and phloem. These two tissues transport fluid and nutrients internally. There are also two meristems associated with vascular tissue:...
contains vessel element
Vessel element
A vessel element is one of the cell types found in xylem, the water conducting tissue of plants. Vessel elements are typically found in the angiosperms but absent from most gymnosperms such as the conifers....
s and in at least some taxa resembles that of the Gnetophyta
Gnetophyta
The plant division Gnetophyta or gnetophytes consists of three genera of woody plants grouped in the gymnosperms. The living Gnetophyta consists of around 70 species across the three genera Gnetum , Welwitschia , and Ephedra .The gnetophytes differ from other gymnosperms The plant division...
. They had a cuticula
Plant cuticle
Plant cuticles are a protective waxy covering produced only by the epidermal cells of leaves, young shoots and all other aerial plant organs without periderm...
similar to that of other seed plants. Some male sporangia (Gigantotheca) and seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
s (Gigantonomia, Cornucarpus) have been tentatively referred to this group. While the sporangia are certainly not flowers, they differ from other sporangia of Permian plants.
Chemical analysis of fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
remains indicates that gigantopterids produced oleanane
Oleanane
Oleanane is a natural triterpene. It forms the central core for a wide variety of chemical compounds found in flowering plants which are referred to collectively as oleanane triterpenes.Some oleanane triterpenes have a suppressing effect on insect pests...
s, chemical compounds otherwise known to be used by flowering plants, for which they function as a suppressant of insect pests. They are apparently also found in certain modern ferns however.
Systematics
It is probable that the gigantopterids are a non-monophyletic form taxonForm taxon
Form classification is the classification of organisms based on their morphology, which does not necessarily reflect their biological relationships...
. Plant life from their era is very difficult to document and organize. They have been variously allied with the "seed ferns" (another paraphyletic group of early seed plants) Peltaspermales and Callistophytales
Callistophytales
The Callistophytales was an order of mainly scrambling and lianescent plants found in the wetland "coal swamps" of Euramerica and Cathaysia. They were characterised by having bilaterally-symmetrical, non-cupulate ovules attached to the underside of pinnules that were morphologically similar to the...
, Gnetum
Gnetum
Gnetum is a genus of about 30-35 species of gymnosperms, the sole genus in the family Gnetaceae and order Gnetales. They are tropical evergreen trees, shrubs and lianas. Unlike other gymnosperms they possess vessel elements in the xylem...
, and the Magnoliophyta. All that can be said at present is that they were spermatophyte
Spermatophyte
The spermatophytes comprise those plants that produce seeds. They are a subset of the embryophytes or land plants...
s. It is also highly unlikely that they were close relatives of gymnosperm
Gymnosperm
The gymnosperms are a group of seed-bearing plants that includes conifers, cycads, Ginkgo, and Gnetales. The term "gymnosperm" comes from the Greek word gymnospermos , meaning "naked seeds", after the unenclosed condition of their seeds...
s, cycads or ginkgos, because these lineages were already established and distinct in the Late Permian.
Vegetative leaves of Emplectopteris were at one time included in this group. However, they had ovules attached to the underside of the fronds and are now placed in their own family (Emplectopteridaceae
Emplectopteridaceae
The Emplectopteridaceae were pteridosperms known mainly from Permian floras of the Cathaysian Realm. They were mostly shrubby plants with a scrambling or upright habit, and favoured a range of habitats from arid to moist or even aquatic...
) within the Callistophytales
Callistophytales
The Callistophytales was an order of mainly scrambling and lianescent plants found in the wetland "coal swamps" of Euramerica and Cathaysia. They were characterised by having bilaterally-symmetrical, non-cupulate ovules attached to the underside of pinnules that were morphologically similar to the...
.
Some prefer to refer to the presumed "core" taxa of this group as Gigantonomiales. However, many experts remain skeptical of the new name, because they consider such a move premature until more is known about the interrelationships of the genera
Genera
Genera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...
of "gigantopterids" and the relationships of these to other plants.
Several genera have been named. Those then known were assigned to a family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Gigantopteridaceae and numerous subfamilies by Gen-ichi Koidzumi
Gen-ichi Koidzumi
was a Japanese botanist, author of several papers and monographs on phytogeography including work on roses and Prunoideae , maples , mulberries , and many other plants. His name is sometimes transliterated as Gen’ichi or Gen-Iti, or as Koizumi.-Published works:* 1956. Plants of Jaluit Island was a...
. It appears as if at least some of his divisions ought to prove useful when a more definite phylogenetic, systematic
Systematic
Systematic is an American hard rock band from Oakland, California. They were one of the first signings to Metallica drummer Lars Ulrich's record label, The Music Company, via Elektra Records. The band released two studio albums before disbanding in 2004....
and taxonomic arrangement for this group is eventually found. On the other hand, the Gigantopteridaceae would with near certainty have to be more narrowly circumscribed even if the Gigantopteridales are by and large verified as a clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
; they might even become limited to the two or so genera now placed in the Gigantopteridieae.
Proposed subfamilies and genera
Cathaysiopteridieae - may be synonym of Palaeogoniopteridieae- Cathaysiopteris
- Cathaysiopteridium
Gigantopteridieae (including Cardioglossieae)
- Gigantonoclea - includes Cardioglossum and apparently Progigantopteris
- Gigantopteris
Gothanopteridieae - may be synonym of Cathaysiopteridieae/Palaeogoniopteridieae
- Gothanopteris
Palaeogoniopteridieae
- Gigantopteridium
- Palaeogoniopteris
- Zeilleropteris
Unresolved
- Delnortea
- Emplectopteridium
- Emplectopteris
- Neogigantopteridium - probably Cathaysiopteridieae/Palaeogoniopteridieae
- Vasovinea
See also
Other Permian-Triassic seed plants of unclear relationships are:- GlossopteridalesGlossopteridalesGlossopteridales is an extinct order of plants belonging to Pteridospermatophyta, or Seed Ferns. They arose at the beginning of the Permian on the southern continent of Gondwana, but dwindled to extinction by the end of the Permian period . The best known genus is Glossopteris.- External links :*...
- Lyginopteridopsida
- Pentoxyales
External links
- Image from Li & Yao (1983), showing fossils and life reconstructions of Gigantonomia (denoted F) and Gigantotheca (denoted V). Retrieved 2007-DEC-12.
- Photo of Delnortea abbottiae leaflet, specimen USNM 387473. Retrieved 2007-DEC-12.
- Reconstruction of Gigantopteris leaves. Retrieved 2007-DEC-12.
- Wikiadugi: Version of this article in Cherokee languageCherokee languageCherokee is an Iroquoian language spoken by the Cherokee people which uses a unique syllabary writing system. It is the only Southern Iroquoian language that remains spoken. Cherokee is a polysynthetic language.-North American etymology:...
. Retrieved 2007-DEC-12.
