Gigantopterid

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Gigantopterids
Temporal range:
Late Permian
 [1]
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Spermatophytes
Division: incertae sedis
Order: †Gigantopteridales
Genera

See text.

Synonyms

Gigantonomiales S.Meyen

Gigantopterids (Gigantopteridales) is an extinct, possibly

angiosperms and/or Bennettitales and/or Caytoniales.[3]

Gigantopterid fossils were documented as early as 1883, but only investigated more thoroughly in the early 20th century. Some of their most significant evidence was initially found in

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.[4]

Description

They bore many of the traits of

reticulate venation arranged in a frond. Gigantopteris nicotianaefolia for example is named thus because each of its leaflets 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 apparently preferred wetlands, while others throve in rather

arid habitats.[5]

The

sporangia (Gigantotheca) and seeds (Gigantonomia, Cornucarpus) have been tentatively referred to this group.[6] While the sporangia are certainly not flowers, they differ from other sporangia of Permian plants.[4]

Chemical analysis of fossil remains indicates that gigantopterids produced oleananes, 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[verification needed].[3]

Systematics

It is probable that the gigantopterids are a non-

cycads or ginkgos, because these lineages were already established and distinct in the Late Permian.[5]

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"

genera of "gigantopterids" and the relationships of these to other plants.[4]

Several genera have been named. Those then known were assigned to a

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.[10]

Proposed subfamilies and genera

Cathaysiopteridieae - may be synonym of Palaeogoniopteridieae

Gigantopteridieae (including Cardioglossieae)

Gothanopteridieae - may be synonym of Cathaysiopteridieae/Palaeogoniopteridieae

Palaeogoniopteridieae

Unresolved

Use as palaeoclimate proxies

Gigantopterids, like the angiosperms of the late Mesozoic and Cenozoic eras, have been used as proxy estimates for palaeoclimate through a process known as foliar physiognomy. Palaeohydroclimate can be estimated based on gigantopteran leaf size, with greater leaf size generally indicating greater precipitation. Additionally, the percentage of entire margined gigantopterid taxa in a palaeobotanical assemblage has been suggested to be a function of palaeotemperature.[12]

See also

Other Permian-Triassic seed plants of unclear relationships are:

Footnotes

  1. S2CID 90421487
    .
  2. ^ Asama (1982)
  3. ^ a b Miller (2007)
  4. ^ a b c Wang (1999)
  5. ^ a b Wang (1999), Glasspool et al. (2004)
  6. ^ Li & Yao (1983)
  7. S2CID 246960147
    .
  8. ^ Meyen (1987)
  9. ^ Koidzumi (1936)
  10. ^ a b Glasspool et al. (2004)
  11. ^ Hongqi Li, B.S., M.S. (1996). "PALEOBIOLOGY OF GIGANTOPTERIDS FROM THE UPPER PERMIAN OF GUIZHOU PROVINCE, CHINA". The Ohio State University. Archived from the original on 2018-07-26.{{cite web}}: CS1 maint: multiple names: authors list (link)
  12. ISSN 0031-0182
    . Retrieved 9 December 2023.

References

External links
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