Pachypteris

Pachypteris (Brongn.) T.M.Harris. is a Mesozoic pteridosperm leaf fossil probably belonging to the seed fern Order Peltaspermales.
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", "Dicroidium" (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).
"Pachypteris" includes about 20 species ranging from late Triassic to Lower Cretaceous, such as "P. speciosa", "P. rhomboidalis", "P. gradinarui", etc. This genus is mainly a boreal taxon, being extensively reported in Europe, Iran, Afghanistan, China and North America, but it has been cited from Gondwanic occurrences as well, such as India, Argentina and Australia.
Distribution.
Fossils of "Pachypteris" have been registered in:
Brazil, China, Germany, Japan, and the Russian Federation
Antarctica, Argentina, Australia, Colombia (Valle Alto Formation, Caldas), France, Georgia, India, Iran, Italy, Japan, Lithuania, Norway, Poland, Romania, the Russian Federation, Serbia and Montenegro, Tajikistan, the United Kingdom, and Uzbekistan.
Argentina