''Lepidopteris'' ("scaly fern") is a

form genus Form classification is the classification of organisms based on their morphology, which does not necessarily reflect their biological relationships. Form classification, generally restricted to palaeontology, reflects uncertainty; the goal of sc ...

for leaves of

Peltaspermaceae The Peltaspermales are an extinct order (biology), order of seed plants, often considered "Pteridospermatophyta, seed ferns". They span from the Late Carboniferous to the Early Jurassic or the Jurassic-Cretaceous Boundary. It includes at least on ...

, an extinct family of

seed plants A seed plant or spermatophyte (; New Latin ''spermat-'' and Greek ' (phytón), plant), also known as a phanerogam (taxon Phanerogamae) or a phaenogam (taxon Phaenogamae), is any plant that produces seeds. It is a category of embryophyte (i.e. la ...

, which lived from around 260 to 190 million years ago, from the 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 251.902 Mya. It is the s ...

to Early Jurassic. Fossils of the genus have been found across both hemispheres. Nine species are currently recognized.''Lepidopteris'' was a common and widespread seed fern, which survived the Permian-Triassic extinction event but was largely wiped out by the Triassic-Jurassic extinction event. ''Lepidopteris callipteroides'' is especially common between the first two episodes of the Permian-Triassic extinction event, and ''L. ottonis'' forms a comparable acme zone immediately 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 Paleobotany or palaeobotany, also known as paleophytology, is the branch of botany dealing with the recovery and identification of plant fossils from geological contexts, and their use for the biological reconstruction of past environments ( pal ...

''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 sporangium, megasporangium), ...

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 (geology), epoch of the Triassic geologic time scale, Period in the geologic time scale, spanning the time between annum, Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch a ...

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. * ''Lepidopteris scassoi'' Early Jurassic of Argentina.

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, assigned to the gymnosperms. The scientific name is also used as the English common name. The order to which the genus belongs, Ginkgoales, first appeared in the Permian, , and ''Ginkgo'' is n ...

'', which has been used to estimate past atmospheric carbon dioxide from its

stoma In botany, a stoma (: stomata, from Greek language, Greek ''στόμα'', "mouth"), also called a stomate (: stomates), is a pore found in the Epidermis (botany), epidermis of leaves, stems, and other organs, that controls the rate of gas exc ...

tal 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 or LATE may refer to: Everyday usage * Tardy, or late, not being on time * Late (or the late) may refer to a person who is dead Music * ''Late'' (The 77s album), 2000 * Late (Alvin Batiste album), 1993 * Late!, a pseudonym used by Dave Groh ...

and

Triassic The Triassic ( ; sometimes symbolized 🝈) is a geologic period and system which spans 50.5 million years from the end of the Permian Period 251.902 million years ago ( Mya), to the beginning of the Jurassic Period 201.4 Mya. The Triassic is t ...

''Lepidopteris'' leaves.

References

External links

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