Sagenopteris

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title: "Sagenopteris" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["pteridospermatophyta", "triassic-first-appearances", "triassic-plants", "jurassic-plants", "early-cretaceous-plants", "early-cretaceous-genus-extinctions", "prehistoric-plant-genera", "fossil-record-of-plants", "mesozoic-antarctica", "mesozoic-life-of-asia", "mesozoic-life-of-europe", "mesozoic-life-of-north-america", "prehistoric-plants-of-north-america", "jurassic-canada", "jurassic-mexico", "jurassic-united-states", "prehistoric-plants-of-south-america", "mesozoic-life-of-south-america", "triassic-argentina", "jurassic-argentina", "fossils-of-argentina", "jurassic-colombia", "fossils-of-colombia", "jurassic-peru", "fossils-of-peru", "fossil-taxa-described-in-1838"] description: "Extinct genus of seed ferns" topic_path: "geography/canada" source: "https://en.wikipedia.org/wiki/Sagenopteris" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Extinct genus of seed ferns ::

| fossil_range = Middle Triassic-Late Cretaceous | image = Sagenopteris_restoration.jpg | image_caption = Illustration showing change in leaf shape of Sagenopteris acuminata during growth, and mature leaves attached to woody stem | taxon = Sagenopteris | authority = Presl 1838 | subdivision_ranks = Species | subdivision = See text

Sagenopteris is a form genus of leaves belonging to the extinct seed plant order Caytoniales, spanning from the Middle Triassic to Late Cretaceous.

Description

::figure[src="https://upload.wikimedia.org/wikipedia/commons/5/51/Sagenopteristrapialensis.jpg" caption="Immature leaf of ''Sagenopteris trapialensis''"] ::

::figure[src="https://upload.wikimedia.org/wikipedia/commons/8/8c/Sagenopteris_phillipsi_Natural_History_Museum_v18596_Retallack_1980.jpg" caption="Mature leaf of ''Sagenopteris phillipsi''"] ::

Sagenopteris has two pairs (making four in total) of palmately arranged leaflets with anastomosing venation and a prominent midrib, which are all attached to the apex of a petiole. Mature leaves are generally lanceolate to oblanceolate, the edges are generally entire (smooth), slightly undulating, and occasionally lobed or dentate (toothed), the cuticle is somewhat thick, and the stomata are only present on the underside (abaxial surface) of the leaflets. According to Xu et al. 2024, the stomata are characterised by "guard cells with a flat surface and a sunken region around the aperture; guard cells typically surrounded by a single ring of weakly modified neighbouring cells in an anomocytic arrangement".

Different organs attributed to the same original plant can be reconstructed from co-occurrence at the same locality and from similarities in the stomatal apparatus and other anatomical peculiarities of fossilized cuticles.

• Sagenopteris phillipsii may have been produced by the same plant as Caytonia nathorstii (ovulate organs) and Caytonanthus arberi (pollen organs).

Species

The following species have been described:

• Sagenopteris colpodes
• Sagenopteris elliptica
• Sagenopteris mclearni
• Sagenopteris nilssoniana
• Sagenopteris oregonensis
• Sagenopteris phillipsii
• Sagenopteris trapialensis
• Sagenopteris variabilis
• Sagenopteris williamsii In a 2024 review, only 5 species, Sagenopteris acuminata (which was designated the lectotype species), S. colpodes, S. hallei, S. phillipsii and S. pualensis were considered valid.

Distribution

Fossils of Sagenopteris have been registered in:

;Triassic Argentina, China, Germany, Greenland, Italy, Japan, Kyrgyzstan, the Russian Federation, Sweden, Tajikistan, Ukraine, United States (Virginia, Virginia/North Carolina).

;Jurassic (to Cretaceous) Afghanistan, Antarctica, Argentina, Azerbaijan, Belarus, Canada (British Columbia, Yukon), China, Colombia (Valle Alto Formation, Caldas), Georgia, Germany, Greenland, India, Iran, Italy, Japan, Kazakhstan, Kyrgyzstan, Mexico, Peru, Poland, Romania, the Russian Federation, Tajikistan, Turkmenistan, Ukraine, the United Kingdom, United States (Alaska, Montana, Oregon/Idaho), and Uzbekistan.

;Cretaceous Spain, Belgium, Canada (British Columbia and Alberta), Greenland, the Russian Federation, and the United States (Montana).

References

References

1. [https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=157221 ''Sagenopteris''] at [[Fossilworks]].org
2. (2019). "Southern Hemisphere Caytoniales: vegetative and reproductive remains from the Lonco Trapial Formation (Lower Jurassic), Patagonia.". Journal of Systematic Palaeontology.
3. (1988). "Reconstructions of selected seed ferns". Missouri Botanical Garden Annals.
4. Bell, W.A. 1956. Lower Cretaceous floras of western Canada; [[Geological Survey of Canada]], Memoir 285, p. 80-81 and plates 31, 33, 34, and 36.
5. Xu, Yuanyuan. (November 2024). "Revision of Sagenopteris (Caytoniales): a major lineage of the Mesozoic seed plants". Papers in Palaeontology.

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::