Umkomasia

{{Short description|Extinct genus of seed ferns}} {{Automatic taxobox | fossil_range = {{fossilrange|Early Triassic|Late Triassic}} | image = Umkomasia macleani.jpg | image_caption = ''Umkomasia macleanii'' ovulate structure, Late Triassic, Molteno Formation, Umkomaas, South Africa. | taxon = Umkomasia | authority = Thomas 1933 | subdivision_ranks = Species | subdivision = * ''Umkomasia feistmantelii'' Early Triassic, Australia * ''Umkomasia macleanii'' Late Triassic South Africa * ?''Umkomasia mongolica'' Early Cretaceous (Aptian-Albian), Mongolia<ref>{{Cite journal|author=Gongle Shi|author2=Andrew B. Leslie|author3=Patrick S. Herendeen|author4=Fabiany Herrera|author5=Niiden Ichinnorov|author6=Masamichi Takahashi|author7=Patrick Knopf|author8=Peter R. Crane|name-list-style=amp |year=2016 |title=Early Cretaceous ''Umkomasia'' from Mongolia: implications for homology of corystosperm cupules |journal=New Phytologist |volume=210 |issue=4 |pages=1418–1429 |doi=10.1111/nph.13871 |pmid=26840646|doi-access=free }}</ref><ref>However, Rothwell & Stockey (2016) transferred this species to the genus ''Doylea''. See: {{Cite journal|author1=Gar W. Rothwell |author2=Ruth A. Stockey |year=2016 |title=Phylogenetic diversification of Early Cretaceous seed plants: The compound seed cone of ''Doylea tetrahedrasperma'' |journal=American Journal of Botany |volume=103 |issue=5 |pages=923–937 |doi=10.3732/ajb.1600030 |pmid=27208360|doi-access=free }}</ref> }}

'''''Umkomasia''''' is a genus of seed bearing organs produced by corystosperm seed ferns, first based on fossils collected by Hamshaw Thomas from the Burnera Waterfall locality near the Umkomaas River of South Africa.<ref name="Thomas-1933">{{cite journal | title=On some pteridospermous plants from the Mesozoic rocks of South Africa | author=Thomas, H.H. | journal=Philosophical Transactions of the Royal Society B | year=1933 | volume=222 | issue=483–493 | pages=193–265 | doi=10.1098/rstb.1932.0016 | doi-access=free }} </ref> He recognized on the basis of cuticular similarities that the same plant produced pollen organs ''Pteruchus'' and the leaves ''Dicroidium''. Various other corystosperm seed bearing organs from the Jurassic and Cretaceous have been assigned to this genus, but recently have been given distinct genera, with ''Umkomasia'' being restricted to the Triassic.<ref>{{Cite journal|last1=Anderson|first1=Heidi M.|last2=Barbacka|first2=Maria K.|last3=Bamford|first3=Marion K.|last4=Holmes|first4=W. B. Keith|last5=Anderson|first5=John M.|date=2019-01-02|title=Umkomasia (megasporophyll): part 1 of a reassessment of Gondwana Triassic plant genera and a reclassification of some previously attributed|url=https://www.tandfonline.com/doi/full/10.1080/03115518.2018.1554748|journal=Alcheringa: An Australasian Journal of Palaeontology|language=en|volume=43|issue=1|pages=43–70|doi=10.1080/03115518.2018.1554748|s2cid=134483119|issn=0311-5518|url-access=subscription}}</ref> [[File:Umkomasia macleani reconstruction.jpg|thumb|left|200px|''Umkomasia macleanii'' reconstruction with pollen organs (''Pteruchus africanus'') and leaves (''Dicroidium odontopteroides'') from the Late Triassic, Molteno Formation of South Africa]]

== Description == Umkomasia has helmet like cupules around ovules born in complex large branching structures.

== Whole plant associations == *''Umkomasia feistmantelii'' from the Early Triassic of Australia may have been produced by the same plant as ''Pteruchus barrealensis'' (pollen organs) and ''Dicroidium zuberi'' (leaves)<ref>{{cite journal | title=Reconstructing Triassic vegetation of southeastern Australia: a new approach to the biostratigraphy of Gondwanaland | author=Retallack G.J. | journal=Alcheringa | year=1977 | volume=1 | pages=247–265 | doi=10.1080/03115517708527763 }} </ref> *''Umkomasia macleanii'' from the Late Triassic of South Africa may have been produced by the same plant as ''Pteruchus africanus'' (pollen organs) and ''Dicroidium odontopteroides'' (leaves)<ref name="Thomas-1933" /><ref>{{Cite journal|title=Reconstructions of selected seed ferns|author1=Retallack, G.J. |author2=Dilcher, D.L. |name-list-style=amp |journal=Missouri Botanical Garden Annals|year=1988|volume=75|issue=3 |pages= 1010–1057 |doi=10.2307/2399379|jstor=2399379 }}</ref>

== Reassigned species ==

* ''U.'' ''franconica'' Lower Jurassic, Germany, reassigned to the genus ''Kirchmuellia'' * ''U. asiatica'' Triassic, China reassigned to the genus ''Stenorachis'' * ''U. mongolica'' Lower Cretaceous, Mongolia, moved to the genus ''Doylea.''

==See also== * Evolution of plants

==References== {{Reflist}}

==External links== *{{cite web|url=https://paleobiodb.org/classic/checkTaxonInfo?taxon_no=157186|title=Fossilworks: Lepidopteris|publisher=paleodb.org|access-date=2016-03-18}}

Category:Permian plants Category:Triassic plants Category:Prehistoric plant genera Category:Pteridospermatophyta Category:Permian first appearances Category:Triassic extinctions