''Pachypteris'' is a

Mesozoic The Mesozoic Era is the Era (geology), era of Earth's Geologic time scale, geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceous Period (geology), Periods. It is characterized by the dominance of archosaurian r ...

pteridosperm 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 ...

("seed fern") genus of fossil leaves. It has either been aligned with the peltasperms or the corystosperms.

Description

''Pachypteris'' is represented by hypostomatic, bipinnate or unipinnate leaves, with alethopteridian venation (midvein and secondary veins divided once or twice before reaching the pinnule margin), pinnules with entire margins and rounded apices. The stomata are haplocheilic, monocyclic or dicyclic, usually depressed, with the guard cells occurring in the lowermost part of the stoma.

Taxonomy

The affinities of ''Pachypteris'' lay with '' Cycadopteris'', ''

Komlopteris ''Komlopteris'' is an extinct genus of "seed fern" with possible corystosperm affinities. Fossils have been found across both hemispheres, dating from the latest Triassic to the early Eocene (Ypresian), making it the youngest "seed fern" in the f ...

'', ''

Dicroidium ''Dicroidium'' is an extinct genus of fork-leaved seed plants. It is the archetypal genus of the corystosperms, an extinct group of seed plants, often called " seed ferns", assigned to the order Corystospermales or Umkomasiales. Species of ''Dic ...

'' (a typical Corystospermalean foliage) and '' Ptilozamites''. It includes the former denomination ''Thinnfeldia'' Ettingshausen 1852, a junior synonym of ''Pachypteris'', as Doludenko (1971) showed. The genus was detailed by Harris (1964), Doludenko (1974), Schweitzer and Kirchner (1998), Popa (2000), and Gordenko (2007). The genus ''Komlopteris'', a segregate from ''Pachypteris'', was defined by Barbacka (1994).Barbacka, M., 1994. ''Komlopteris'' Barbacka, gen. nov., a segregate from ''Pachypteris'' Brongniart. Review of Palaeobotany and Palynology(83): 339–349. ''Pachypteris'' includes about 20 species ranging from late

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 ...

to Lower

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

, such as ''P. speciosa'', ''P. rhomboidalis'', ''P. gradinarui'', etc. This genus is mainly a boreal taxon, being extensively reported in

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

Iran Iran, officially the Islamic Republic of Iran (IRI) and also known as Persia, is a country in West Asia. It borders Iraq to the west, Turkey, Azerbaijan, and Armenia to the northwest, the Caspian Sea to the north, Turkmenistan to the nort ...

Afghanistan Afghanistan, officially the Islamic Emirate of Afghanistan, is a landlocked country located at the crossroads of Central Asia and South Asia. It is bordered by Pakistan to the Durand Line, east and south, Iran to the Afghanistan–Iran borde ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

and

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

, but it has been cited from Gondwanic occurrences as well, such as

India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

and

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

Distribution

Fossils of ''Pachypteris'' have been registered in:''Pachypteris''
at

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.org

Triassic

Brazil, China, Germany, Japan, and the Russian Federation

Jurassic

Antarctica, Argentina, Australia, Colombia (

Valle Alto Formation The Valle Alto Formation (, Jva) is a geological formation of the Central Ranges of the Colombian Andes. The formation is composed of shales, sandstones and conglomerates and dates to the Late Jurassic period. Ammonites and fossil flora have been ...

, Caldas), France, Georgia, India, Iran, Italy, Japan, Lithuania, Norway, Poland, Romania, the Russian Federation, Serbia and Montenegro, Tajikistan, the United Kingdom, and Uzbekistan.

Cretaceous

Argentina

References

{{Taxonbar, from=Q7122207 Pteridospermatophyta Early Triassic genus first appearances Olenekian genera Anisian genera Ladinian genera Carnian genera Norian genera Rhaetian genera Hettangian genera Sinemurian genera Pliensbachian genera Toarcian genera Aalenian genera Bajocian genera Bathonian genera Callovian genera Oxfordian genera Kimmeridgian genera Tithonian genera Berriasian genera Valanginian genera Hauterivian genera Barremian genera Aptian genera Albian genera Cenomanian genera Triassic plants Jurassic plants Early Cretaceous plants Late Cretaceous plants Late Cretaceous genus extinctions Mesozoic Antarctica Mesozoic life of Asia Mesozoic life of Europe Mesozoic life of South America Prehistoric plants of South America Triassic Brazil Fossils of Brazil Jurassic Argentina Cretaceous Argentina Fossils of Argentina Jurassic Colombia Fossils of Colombia Fossil taxa described in 1828 Fossils of Serbia