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 fossil record.

Morphology

Within the form classification system used in paleobotany, ''Komlopteris'' is used to refer to leaves. The leaves are generally lanceolate to slightly falcate, though some are ovate, and form a pinnate arrangement, and are sometimes bipinnate. The cuticles are thick, with at least some having resin bodies within the leaves.

Ecology

Gondwanan ''Komlopteris'' species are often associated with fern dominated, humid temperate forested habitats. The finding of numerous leaves of ''Komlopteris'' in single leaf mat layers suggests that at least some species were deciduous. A 1998 study suggested that the type species ''Komlopteris nordenskioeldii'' likely grew as a tree, based on the presence of distinct sun and shade leaves, as is found in living angiosperm trees.

Affinities

''Komlopteris'' is not known to be definitively associated with any reproductive organs, though corystoperm-like ovulate and pollen producing reproductive organs, as well as corystosperm-like '' Alisporites''/'' Falcisporites'' pollen have been found in the same strata at a number of localities. Its leaf architecture and venation closely resembles that of the archetypal corystosperm ''Dicroidium,'' as well as to '' Kurtziana'' and ''Pachypteris,'' which are also suggested to be a corystoperms, with the particularly close resemblance to ''Kurtziana'' leading to suggestions that they form part of the same lineage. However, some authors have suggested that the ovulate reproducive organ ''Sacculotheca'' from the Early Jurassic of Hungary, which co-occurs with ''Komlopteris'' and shares a similar stomatal pattern, is part of the same plant. ''Sacculotheca'' differs strongly in morphology from typical corystosperm reproductive organs like '' Umkomasia'', meaning that if its association with ''Komlopteris'' is real, it would bring its corystosperm affinities into doubt.

Taxonomy

''Komlopteris'' was named by Barbacka in 1994, to include leaves originally included in '' Thinnfeldia'' and ''Pachypteris.'' The type species is ''K. nordenskioeldii,'' known from the earliest Jurassic (Hettangian) of Sweden, as well as other parts of Europe like Hungary ( Mecsek Coal Formation). Other Northern Hemisphere species include ''K. rotundata'' from the Late Triassic (Rhaetian) of Sweden, ''K. speciosa'' from the Middle Jurassic (Bathonian) Taynton Limestone Formation of England, and ''K''. ''distinctiva'' from the Early Jurassic of Poland. The oldest species from Gondwana are from Argentina, dating to the Early Jurassic, assigned to the species, ''K''. ''artabeae'' and ''K. nestarensis ,''which were originally assigned to the genus ''Alicurana,'' which was considered a synonym of ''Komlopteris'' in a 2023 review of the genus. Species known from the Late Jurassic include ''K. khatangiensis'' from India, ''K. constricta'' from the Antarctic Peninsula, and ''K''. ''purlawaughensis'' from the Talbragar Fish Bed in NSW, Australia. ''K''. ''tiruchirapalliense'' is known from the Early Cretaceous of both southern India and Western Australia. Other Early Cretaceous species include ''K''. ''indica'' from the Indian subcontinent, ''K''. ''boolensis'' from Australia (Victoria and Queensland), and ''K''. ''victoriensis'' from the Early Cretaceous of Victoria, Australia and New Zealand, and the early Late Cretaceous (Cenomanian) of Queensland, Australia. The youngest known species is ''K. cenozoicus'' from the early Eocene (Ypresian) of Tasmania, which are the youngest known remains of any "seed fern".

References

{{Taxonbar, from=Q122695862

Pteridospermatophyta
Prehistoric plant genera