The Peltaspermales are an extinct

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

seed plant 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 ...

s, often considered "

seed ferns Pteridospermatophyta, also called pteridosperms or seed ferns, are a polyphyletic grouping of extinct Spermatophyte, seed-producing plants. The earliest fossil evidence for plants of this type are the Lyginopteridales, lyginopterids of late Devon ...

". They span from the Late Carboniferous to the Early Jurassic or the Jurassic-Cretaceous Boundary. It includes at least one valid family, Peltaspermaceae, which spans from the Permian to Early Jurassic, which is typified by a group of plants with ''

Lepidopteris ''Lepidopteris'' ("scaly fern") is a form classification, form genus for leaves of Peltaspermaceae, an extinct family of seed plants, which lived from around 260 to 190 million years ago, from the Late Permian to Early Jurassic. Fossils of the ge ...

'' leaves, '' Antevsia'' pollen-organs, and '' Peltaspermum''

ovulate Ovulation is an important part of the menstrual cycle in female vertebrates where the egg cells are released from the ovaries as part of the ovarian cycle. In female humans ovulation typically occurs near the midpoint in the menstrual cycle and ...

organs, though the family now also includes other genera like '' Peltaspermopsis'', '' Meyenopteris'' and '' Scytophyllum''. Along with these, two informal groups (the " Supaioids" DiMichele, William A., Chaney, Dan S., Lucas, Spencer G., Kerp, Hans, and Voigt, Sebastian. 2013
"Flora of the Lower Permian Abo Formation redbeds, western equatorial Pangea, New Mexico."
''New Mexico Museum of Natural History and Science Bulletin'', 59 265–288. and the " Comioids"Chaney, Dan S., Mamay, Serguis H., DiMichele, William A., and Kerp, Hans. 2009. "''Auritifolia'' gen. nov., Probable Seed Plant Foliage with Comioid Affinities from the Early Permian of Texas, U.S.A." ''International Journal of Plant Sciences'', 170, (2) 247–266. https://doi.org/10.1086/595293. ) of uncertain taxonomic affinities exist, each centered around a specific genus; ''

Supaia ''Supaia'' is an extinct genus of fern-like plants, possibly seed ferns. Species belonging to the genus lived during the Permian The Permian ( ) is a geologic period and System (stratigraphy), stratigraphic system which spans 47 million years, ...

'' and '' Comia,'' known from the Early Permian of the Northern Hemisphere, especially of North America. Both the "Comioids" and the "Supaioids" are associated with the peltaspermacean ovulate organ '' Autunia'' (also known as ''Sandrewia''). The Late Triassic-Middle Jurassic genus '' Pachydermophyllum'' may also have affinities to the peltasperms. The morphology of peltasperm leaves is highly variable, ranging from dissected

pinnate Pinnation (also called pennation) is the arrangement of feather-like or multi-divided features arising from both sides of a common axis. Pinnation occurs in biological morphology, in crystals, such as some forms of ice or metal crystals, and ...

(fern-like) to forked and

simple Simple or SIMPLE may refer to: *Simplicity, the state or quality of being simple Arts and entertainment * ''Simple'' (album), by Andy Yorke, 2008, and its title track * "Simple" (Florida Georgia Line song), 2018 * "Simple", a song by John ...

morphologies. The leaves of many peltasperms have "monocyclic

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 ...

ta with wedge-shaped subsidiaries ending in a beak-like papilla overarching the guard cells", something which is found among other seed plant groups. The seed-bearing organs are generally fan-shaped or peltate. It is unclear whether the broad grouping of peltasperms as a whole is

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

. Some authors have suggested that some peltasperms may have close affinities to corystosperms, another group of extinct "seed ferns". Meyen (1987) argued that Peltaspermales were ancestral to

Ginkgoales Ginkgoales are a gymnosperm Order (biology), order containing only one Neontology, extant species: ''Ginkgo biloba'', the ginkgo tree. The order has a long fossil record extending back to the Early Permian around 300 million years ago from fossi ...

, due to similarities between certain peltasperm form genera ('' Tatarina'', '' Kirjamkenia'', '' Stiphorus'', ''Antevsia'') and the extinct gingko ''

Glossophyllum ''Glossophyllum'' is an extinct genus of plants known from fossilized leaves of the Triassic of Eurasia, with affinities to Ginkgoales. The leaves are elongate relative to modern ''Ginkgo'', being lanceolate, strap or tongue shaped. Description ...

,'' and grouped peltasperms with Ginkgoales as part of

Ginkgoopsida Ginkgoopsida is a proposed class of gymnosperms defined by Sergei V. Meyen in 1984 to encompass Ginkgoales (which contains the living ''Ginkgo'') alongside a number of extinct seed plant groups, which he considered to be closely related based on ...

. Later authors have considered the position of Peltaspermales within seed plants to be uncertain. It is suggested that at least some peltasperms may have been

insect pollinated Entomophily or insect pollination is a form of pollination whereby pollen of plants, especially but not only of flowering plants, is distributed by insects. Flowers pollinated by insects typically advertise themselves with bright colours, somet ...

, with Pemian members of the long- probiscis

scorpionfly Mecoptera (from the Greek language, Greek: ''mecos'' = "long", ''ptera'' = "wings") is an Order (biology), order of insects in the superorder Holometabola with about six hundred species in nine Family (biology), families worldwide. Mecopterans a ...

family Protomeropidae from Russia associated with peltasperm pollen. The insects are suggested to have fed on pollination drops produced by peltasperm reproductive organs.

Evolutionary history

During the late Paleozoic, peltasperms are primarily known from the Northern Hemisphere, with ''Lepidopteris'' first appearing in the region during the Late Permian. During the

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'' became globally distributed and was abundant, especially during the Late Triassic. ''Lepidopteris'' populations collapsed during the end-Triassic mass extinction, with small populations persisting in Patagonia into the Early Jurassic. The genus '' Pachydermophyllum'', along specimens referred as ''Lepidopteris?'' from the Battle Camp Formation of

Clack Island Clack Island is part of the Great Barrier Reef Marine Park at the tip of Cape Melville, Queensland in Bathurst Bay, Australia. It is north-east of Denham Island and Flinders Island in the Flinders Group National Park Flinders Group Nation ...

, of latest Jurassic or earliest Cretaceous age may indicate an even longer survival in Gondwana.

Families, genera, and other groupings

* Family Peltaspermaceae ** ''

'' (leaves) ** '' Antevsia'' (pollen organs) ** '' Peltaspermum'' (ovulate organ) ** '' Peltaspermopsis'' (ovulate organ) ** '' Meyenopteris'' (ovulate organ) ** '' Kirjamkenia'' (leaves) ** '' Scytophyllum'' (leaves) ** '' Tatarina'' (leaves) * "Supaioids" ** ''

'' (leaves) ** '' Glenopteris'' (leaves) ** '' Compsopteris'' (leaves) ** '' Brongniartites'' (leaves) * "Comioids" ** '' Comia'' (leaves) ** '' Auritifolia'' (leaves) * '' Autunia'' (ovulate organ, formerly ''Sandrewia'') * '' Autuniopsis'' (ovulate organ) * '' Lopadiangium'' (ovulate organ) * '' Navipelta'' (ovulate organ) * '' Permoxylocarpus'' (ovulate organ) * '' Sporophyllites'' (ovulate organ) * '' Stiphorus'' (ovulate organ) * '' Tinsleya'' (ovulate organ) * '' Pachydermophyllum''? (leaves) * '' Vittaephyllum'' (leaves) * '' Taimyria'' (ovulate organ) * ''

Furcula The (Latin for "little fork"; : furculae) or wishbone is a forked bone found in most birds and some species of non-avian dinosaurs, and is either an interclavicle or formed by the fusion of the two clavicles. In birds, its primary function is ...

'' (leaves) * Matatiellaceae? (Other authors consider this family to be ''incertae sedis'' within seed plants) ** '' Dejerseya'' (leaves) ** '' Matatiella'' (ovulate organ)

References

{{Taxonbar, from=Q1536417 Permian plants Triassic plants Prehistoric plant orders Permian first appearances Triassic extinctions