https://en.bharatpedia.org/w/index.php?action=history&feed=atom&title=Sahnioxylon_rajmahalenseSahnioxylon rajmahalense - Revision history2026-10-27T14:04:45ZRevision history for this page on the wikiMediaWiki 1.43.6https://en.bharatpedia.org/w/index.php?title=Sahnioxylon_rajmahalense&diff=425052&oldid=prevAjay Kumar: Creating a new article2023-09-04T17:10:43Z<p>Creating a new article</p>
<p><b>New page</b></p><div>{{Short description|Species of prehistoric plant}}<br />
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{{Speciesbox<br />
| fossil_range = {{fossil range|Middle Triassic|Late Cretaceous}}<br />
| genus = Sahnioxylon<br />
| species = rajmahalense<br />
| authority = ([[Birbal Sahni|Sahni]]) M.N. Bose, S.C.D. Sah<br />
| synonyms = *''Homoxylon rajmahalense''<br />
| synonyms_ref = <ref>{{fossilworks |id=414190 |title=''Sahnioxylon rajmahalense'' |date=8 November 2022}}</ref><br />
}}<br />
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'''''Sahnioxylon rajmahalense''''' was a piece of secondary wood found in the [[Rajmahal hills|Rajmahal Hills]] of [[Bengal]], northwest to [[Kolkata|Calcutta]]. It was described by [[Birbal Sahni]] in 1954, and later that year S. andrewsii was found by [[Pramatha Nath Bose|Bose]] & Sah in the same general area. Although it’s exact location of excavation is unknown, evidence states that it ranged from the [[Triassic|lower Triassic Period]], until the [[Upper Cretaceous]]. The fossil of the leaves resemble a [[gymnosperm]] in that it has no vessels, yet the [[tracheid]] walls bear a mixture of scalariform.<ref>{{Cite web |date=2016-08-30 |title=Fossil Anglosperms of a Plant |url=https://www.biologydiscussion.com/angiosperms/fossil-anglosperms-of-a-plant/47716 |access-date=2022-11-15 |website=Biology Discussion |language=en-US}}</ref><ref>{{Cite web |date=2016-08-30 |title=Fossil Anglosperms of a Plant |url=https://www.biologydiscussion.com/angiosperms/fossil-anglosperms-of-a-plant/47716 |access-date=2023-09-04 |website=Biology Discussion |language=en-US}}</ref><br />
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== History ==<br />
The [[Form classification|form-genus]] ''Sahnioxylon'' was first coined by [[paleobotanist]] [[Birbal Sahni]], and is used for fossilized woods, whose primitive features place them in between [[Cycadeoidea]], [[Gnetales]], and homoxylous [[angiosperms]]. These plants have been found in [[Siberia]], [[India]], [[Antarctica]], [[Romania]], [[Central Asia|Middle-Asia]], and [[New Caledonia|New-Caledonia]]. Thus it seems that the genus be of little [[Biogeography|paleobiogeographical]] interest. A [https://www.researchgate.net/publication/280140532 review] by Torres and Phillipe proposes to keep the species below within ''Sahnioxylon''.<ref name="auto">{{Cite web|url=https://www.researchgate.net/publication/280140532_Sahnioxylon_a_Mesozoic_wood_with_a_loose_distribution_China_India_and_western_Antarctica|title=(PDF) Sahnioxylon, a Mesozoic wood with a loose distribution: China, India and western Antarctica}}</ref><ref>{{Cite journal |last=Yadav |first=R. R. |last2=Bhattacharyya |first2=A. |date=1994 |title=Growth ring features in Sahnioxylon from Rajmahal Hills and their climatic implications |url=https://www.jstor.org/stable/24095849 |journal=Current Science |volume=67 |issue=9/10 |pages=739–740 |issn=0011-3891}}</ref><br />
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# ''S. andrewsii'': [[Pramatha Nath Bose|Bose]] & Sah, 1954 ([[Rajmahal hills|Rajmahal Hills]], [[India]], [[Late Jurassic]] or [[Early Cretaceous]]); <br />
# ''S. antarcticum'': Lemoigne & Torres, 1988 ([[South Shetland Islands|South Shetland]], [[Antarctica]], [[Late Cretaceous]]); <br />
# ''S. rajmahalense'': ([[Birbal Sahni|Sahni]]) [[Pramatha Nath Bose|Bose]] & Sah, 1954 ([[Rajmahal hills|Rajmahal Hills]], [[India]], [[Late Jurassic]] or [[Early Cretaceous]]);<br />
# ''S. seward'': Kumarasamy & Jeyasingh, 1995 ([[Madras|Madras area]], [[India]], [[Early Cretaceous]], maybe conspecific with Mesembrioxylon seward [[Birbal Sahni|Sahni]] 1931).<ref name="auto"/><br />
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== Distribution ==<br />
The article by Torres and Phillipe stated that “the distribution of ''Sahnioxylon'', is astonishing and does not comply with [[Mesozoic]] vegetation maps as proposed, for example, by Vakhrameev [1991].” Further in their article they stated 3 hypotheses on how the [[gymnosperm]] has been found in [[Deposition (geology)|deposits]] all over the world.<ref name="auto"/><br />
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# The first bias is that data is lacking. The range of the plant could be larger but is unidentified. It may, in places, not be preserved, found, or published. In rebuttal to the [[hypothesis]], is that [[sediment]]s similar to the ones found in Sahnioxylon [[Type locality (geology)|localities]] are all over the world.<ref>{{Cite journal |date=2022-02-25 |title=On Sahnioxylon Rajmahalense, a new name for Homoxylon Rajmahalense Sahni, and S. Andrewsii, a new species of Sahnioxylon from Amrapara in the Rajmahal Hills, Bihar {{!}} Journal of Palaeosciences |url=https://jpsonline.co.in/index.php/jop/article/view/443 |language=en-US}}</ref><br />
#The next bias is that samples that actually belong to Sahnioxylon, have not been described as such.<br />
#The final possibility is that of [[parallel evolution]].<ref name="auto"/><br />
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== References ==<br />
{{Reflist}}<br />
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[[Category:Prehistoric gymnosperm genera]]<br />
[[Category:Cycads]]</div>Ajay Kumar