Siwalik plant megafossil diversity in the Eastern Himalayas: A review

The Eastern Himalayas are renowned for their high plant diversity. To understand how this modern botanical richness formed, it is critical to investigate past plant biodiversity preserved as fossils throughout the eastern Himalayan Siwalik succession (middle Miocene−early Pleistocene). Here, we pres...

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Main Authors: Mahasin Ali Khan, Sumana Mahato, Robert A. Spicer, Teresa E.V. Spicer, Ashif Ali, Taposhi Hazra, Subir Bera
Format: Article
Language:English
Published: KeAi Communications Co., Ltd. 2023-05-01
Series:Plant Diversity
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2468265922001287
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author Mahasin Ali Khan
Sumana Mahato
Robert A. Spicer
Teresa E.V. Spicer
Ashif Ali
Taposhi Hazra
Subir Bera
author_facet Mahasin Ali Khan
Sumana Mahato
Robert A. Spicer
Teresa E.V. Spicer
Ashif Ali
Taposhi Hazra
Subir Bera
author_sort Mahasin Ali Khan
collection DOAJ
description The Eastern Himalayas are renowned for their high plant diversity. To understand how this modern botanical richness formed, it is critical to investigate past plant biodiversity preserved as fossils throughout the eastern Himalayan Siwalik succession (middle Miocene−early Pleistocene). Here, we present a summary of plant diversity records that document Neogene floristic and climate changes. We do this by compiling published records of megafossil plant remains, because these offer better spatial and temporal resolution than do palynological records. Analyses of the Siwalik floral assemblages based on the distribution of the nearest living relative taxa suggest that a tropical wet evergreen forest was growing in a warm humid monsoonal climate at the deposition time. This qualitative interpretation is also corroborated by published CLAMP (Climate Leaf Analysis Multivariate Program) analyses. Here, we also reconstruct the climate by applying a new common proxy WorldClim2 calibration. This allows the detection of subtle climate differences between floral assemblages free of artefacts introduced by using different methodologies and climate calibrations. An analysis of the Siwalik floras indicates that there was a gradual change in floral composition. The lower Siwalik assemblages provide evidence of a predominance of evergreen elements. An increase in deciduous elements in the floral composition is noticed towards the close of the middle Siwalik and the beginning of the upper Siwalik formation. This change reflects a climatic difference between Miocene and Plio-Pleistocene times. This review helps us to understand under what paleoenvironmental conditions plant diversity occurred and evolved in the eastern Himalayas throughout the Cenozoic.
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spelling doaj.art-a151abeac04441f4acc4765e92f76d3d2023-06-18T05:03:06ZengKeAi Communications Co., Ltd.Plant Diversity2468-26592023-05-01453243264Siwalik plant megafossil diversity in the Eastern Himalayas: A reviewMahasin Ali Khan0Sumana Mahato1Robert A. Spicer2Teresa E.V. Spicer3Ashif Ali4Taposhi Hazra5Subir Bera6Palaeobotany and Palynology Laboratory, Department of Botany, Sidho-Kanho-Birsha University, Ranchi Road, Purulia 723104, India; Corresponding author.Palaeobotany and Palynology Laboratory, Department of Botany, Sidho-Kanho-Birsha University, Ranchi Road, Purulia 723104, IndiaCAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, PR China; School of Environment, Earth and Ecosystem Sciences, The Open University, Milton Keynes, MK7 6AA, UKCAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla 666303, PR ChinaPalaeobotany and Palynology Laboratory, Department of Botany, Sidho-Kanho-Birsha University, Ranchi Road, Purulia 723104, IndiaPalaeobotany and Palynology Laboratory, Department of Botany, Sidho-Kanho-Birsha University, Ranchi Road, Purulia 723104, IndiaCentre of Advanced Study, Department of Botany, University of Calcutta, 35, B.C. Road, Kolkata 700019, IndiaThe Eastern Himalayas are renowned for their high plant diversity. To understand how this modern botanical richness formed, it is critical to investigate past plant biodiversity preserved as fossils throughout the eastern Himalayan Siwalik succession (middle Miocene−early Pleistocene). Here, we present a summary of plant diversity records that document Neogene floristic and climate changes. We do this by compiling published records of megafossil plant remains, because these offer better spatial and temporal resolution than do palynological records. Analyses of the Siwalik floral assemblages based on the distribution of the nearest living relative taxa suggest that a tropical wet evergreen forest was growing in a warm humid monsoonal climate at the deposition time. This qualitative interpretation is also corroborated by published CLAMP (Climate Leaf Analysis Multivariate Program) analyses. Here, we also reconstruct the climate by applying a new common proxy WorldClim2 calibration. This allows the detection of subtle climate differences between floral assemblages free of artefacts introduced by using different methodologies and climate calibrations. An analysis of the Siwalik floras indicates that there was a gradual change in floral composition. The lower Siwalik assemblages provide evidence of a predominance of evergreen elements. An increase in deciduous elements in the floral composition is noticed towards the close of the middle Siwalik and the beginning of the upper Siwalik formation. This change reflects a climatic difference between Miocene and Plio-Pleistocene times. This review helps us to understand under what paleoenvironmental conditions plant diversity occurred and evolved in the eastern Himalayas throughout the Cenozoic.http://www.sciencedirect.com/science/article/pii/S2468265922001287MegafossilsSiwalikMiocene−PleistocenePalaeovegetationPalaeoenvironmentEastern Himalayas
spellingShingle Mahasin Ali Khan
Sumana Mahato
Robert A. Spicer
Teresa E.V. Spicer
Ashif Ali
Taposhi Hazra
Subir Bera
Siwalik plant megafossil diversity in the Eastern Himalayas: A review
Plant Diversity
Megafossils
Siwalik
Miocene−Pleistocene
Palaeovegetation
Palaeoenvironment
Eastern Himalayas
title Siwalik plant megafossil diversity in the Eastern Himalayas: A review
title_full Siwalik plant megafossil diversity in the Eastern Himalayas: A review
title_fullStr Siwalik plant megafossil diversity in the Eastern Himalayas: A review
title_full_unstemmed Siwalik plant megafossil diversity in the Eastern Himalayas: A review
title_short Siwalik plant megafossil diversity in the Eastern Himalayas: A review
title_sort siwalik plant megafossil diversity in the eastern himalayas a review
topic Megafossils
Siwalik
Miocene−Pleistocene
Palaeovegetation
Palaeoenvironment
Eastern Himalayas
url http://www.sciencedirect.com/science/article/pii/S2468265922001287
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