''Lepidopteris'' ("scaly fern") is a form genus for leaves of Late

Permian The Permian ( ) is a geologic period and System (stratigraphy), 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 ...

to Late

Triassic The Triassic ( ) is a geologic period and system (stratigraphy), system which spans 50.6 million years from the end of the Permian Period 251.902 million years ago (Year#Abbreviations yr and ya, Mya), to the beginning of the Jurassic Period 201.36 ...

Period Period may refer to: Common uses * Era, a length or span of time * Full stop (or period), a punctuation mark Arts, entertainment, and media * Period (music), a concept in musical composition * Periodic sentence (or rhetorical period), a concept ...

Pteridospermatophyta The term Pteridospermatophyta (or "seed ferns" or "Pteridospermatopsida") is a polyphyletic group of extinct seed-bearing plants (spermatophytes). The earliest fossil evidence for plants of this type is the genus ''Elkinsia'' of the late Devonia ...

, or seed ferns, which lived from around 260 to 200 million years ago in what is now Australia,

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and China. Nine species are currently recognized. ''Lepidopteris'' was a common and widespread seed fern, which survived the Permian-Triassic extinction event but succumbed to 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.''

Description

In the form generic system of paleobotany ''Lepidopteris'' is used only for leaves, which are fern-like with pinnules attached to the rachis as well as the pinnae. The cuticle of the leaves is thick and has a distinctive cuticular structure with stomatal opening overhung by papillae. This structure has been used to link the fossil leaves with well preserved reproductive structures in the same deposits. The

ovule In seed plants, the ovule is the structure that gives rise to and contains the female reproductive cells. It consists of three parts: the '' integument'', forming its outer layer, the ''nucellus'' (or remnant of the megasporangium), and the ...

s are commonly arranged in peltate structures, which have been used to assign ''Lepidopteris'' to the Order Peltaspermales. Not all leaf species are associated with reproductive material, but well established associations include the following. * ''Lepidopteris ottonis'' (leaves), ''Peltaspermum rotula'' (ovulate structures) and ''Antevsia zeilleri'' (pollen organ). * '' Lepidopteris stormbergensis'' (leaves), ''Peltaspermum thomasii'' (ovulate structures) and ''Antevsia extans'' (pollen organ). * '' Lepidopteris callipteroides'' (leaves), ''Peltaspermum townrovii'' (ovulate structures) and ''Permotheca helbyi'' (pollen organ).

Distribution and species

''Lepidopteris'' was geographically widespread and ranged from Late

Late Triassic The Late Triassic is the third and final epoch of the Triassic Period in the geologic time scale, spanning the time between Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch and followed by the Early Jurassic Epoch. ...

but individual species had more restricted geographic extent and shorter stratigraphic ranges, as seen in the list below in stratigraphic order * ''Lepidopteris martinsii'' from Late Permian of Germany, England and Italy. * '' Lepidopteris callipteroides'' from Late Permian of Madagascar and Australia. * ''Lepidopteris madagascariensis'' from Early Triassic of Madagascar and Australia. * '' Lepidopteris stormbergensis'' from Middle-Late Triassic of South Africa, India, South America and Australia. * ''Lepidopteris remota'' from Middle Triassic of Russia. * ''Lepidopteris haizeri'' from Middle to Late Triassic of Russia * ''Lepidopteris heterolateralis'' from Middle to Late Triassic of Russia. * ''Lepidopteris microcellularis'' from Middle to Late Triassic of Russia. * ''Lepidopteris ottonis'' from Late Triassic of Greenland, Germany, Poland, China and Vietnam.

Atmospheric carbon dioxide paleobarometer

The cuticular structure of ''Lepidopteris'' is comparable to that of modern ''

Ginkgo ''Ginkgo'' is a genus of non-flowering seed plants. The scientific name is also used as the English name. The order to which it belongs, Ginkgoales, first appeared in the Permian, 270 million years ago, and is now the only living genus with ...

'', which has been used to estimate past atmospheric carbon dioxide from its stomatal index. Because ''Lepidopteris'' and ''

'' leaves in the same South African fossil quarries have the same stomatal index, the calibration for modern ''

'' has been used to calculate carbon dioxide levels from

Late Permian Late may refer to: * LATE, an acronym which could stand for: ** Limbic-predominant age-related TDP-43 encephalopathy, a proposed form of dementia ** Local-authority trading enterprise, a New Zealand business law ** Local average treatment effect, ...

and

''Lepidopteris'' leaves.

References

External links

{{Taxonbar, from=Q16984362 Permian plants Triassic plants Prehistoric plant genera Pteridospermatophyta Guadalupian first appearances Late Triassic extinctions