Evidence of the oldest extant vascular plant (horsetails) from the Indian Cenozoic
Equisetum (Equisetaceae) has long been a focus of attention for botanists and palaeontologists because, given its extensive and well-documented fossil record, it is considered the oldest extant vascular plant and a key element in understanding vascular plant evolution. However, to date, no authentic...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
KeAi Communications Co., Ltd.
2023-09-01
|
| Series: | Plant Diversity |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2468265923000215 |
| _version_ | 1797653651451281408 |
|---|---|
| author | Sampa Kundu Taposhi Hazra Tapan Chakraborty Subir Bera Mahasin Ali Khan |
| author_facet | Sampa Kundu Taposhi Hazra Tapan Chakraborty Subir Bera Mahasin Ali Khan |
| author_sort | Sampa Kundu |
| collection | DOAJ |
| description | Equisetum (Equisetaceae) has long been a focus of attention for botanists and palaeontologists because, given its extensive and well-documented fossil record, it is considered the oldest extant vascular plant and a key element in understanding vascular plant evolution. However, to date, no authentic fossil evidence of Equisetum has been found from the Indian Cenozoic. Here, we describe a new fossil species, namely, E. siwalikum sp. nov., recovered from the middle Siwalik (Late Miocene) sediments of Himachal Pradesh, western Himalaya. We identified fossil specimens based on morphological and epidermal characters. In addition, X-Ray diffraction (XRD) analysis was used to determine the mineral composition of compressed stems of Equisetum. The close affinity of our recovered Siwalik fossils to Equisetum is supported by the presence of both macromorphological and epidermal characters. Because Equisetum generally grows in wet conditions around water reservoirs, our findings indicate that the fossil locality was humid and surrounded by swamp and lowland regions during deposition. Ample fossil evidence indicates that this sphenopsid once existed in the western Himalaya during the Siwalik period. However, at present Equisetum is confined to a particular area of our fossil locality, probably a consequence of severe environmental changes coupled with competition from opportunistic angiosperms. Our discovery of Equisetum fossils in appreciable numbers from the Siwalik sediments of the Himachal Himalayas is unique and constitutes the first reliable recognition of Equisetum from the Indian Cenozoic. |
| first_indexed | 2024-03-11T16:47:41Z |
| format | Article |
| id | doaj.art-df6e8f298c2446fbac0eff01c23761f0 |
| institution | Directory Open Access Journal |
| issn | 2468-2659 |
| language | English |
| last_indexed | 2024-03-11T16:47:41Z |
| publishDate | 2023-09-01 |
| publisher | KeAi Communications Co., Ltd. |
| record_format | Article |
| series | Plant Diversity |
| spelling | doaj.art-df6e8f298c2446fbac0eff01c23761f02023-10-22T04:49:35ZengKeAi Communications Co., Ltd.Plant Diversity2468-26592023-09-01455569589Evidence of the oldest extant vascular plant (horsetails) from the Indian CenozoicSampa Kundu0Taposhi Hazra1Tapan Chakraborty2Subir Bera3Mahasin Ali Khan4Palaeobotany 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, IndiaGeological Studies Unit, Indian Statistical Institute, 203, B.T. Road, Kolkata 700108, West Bengal, IndiaCentre of Advanced Study, Department of Botany, University of Calcutta, 35, B.C. Road, Kolkata 700019, IndiaPalaeobotany and Palynology Laboratory, Department of Botany, Sidho-Kanho-Birsha University, Ranchi Road, Purulia 723104, India; Corresponding author.Equisetum (Equisetaceae) has long been a focus of attention for botanists and palaeontologists because, given its extensive and well-documented fossil record, it is considered the oldest extant vascular plant and a key element in understanding vascular plant evolution. However, to date, no authentic fossil evidence of Equisetum has been found from the Indian Cenozoic. Here, we describe a new fossil species, namely, E. siwalikum sp. nov., recovered from the middle Siwalik (Late Miocene) sediments of Himachal Pradesh, western Himalaya. We identified fossil specimens based on morphological and epidermal characters. In addition, X-Ray diffraction (XRD) analysis was used to determine the mineral composition of compressed stems of Equisetum. The close affinity of our recovered Siwalik fossils to Equisetum is supported by the presence of both macromorphological and epidermal characters. Because Equisetum generally grows in wet conditions around water reservoirs, our findings indicate that the fossil locality was humid and surrounded by swamp and lowland regions during deposition. Ample fossil evidence indicates that this sphenopsid once existed in the western Himalaya during the Siwalik period. However, at present Equisetum is confined to a particular area of our fossil locality, probably a consequence of severe environmental changes coupled with competition from opportunistic angiosperms. Our discovery of Equisetum fossils in appreciable numbers from the Siwalik sediments of the Himachal Himalayas is unique and constitutes the first reliable recognition of Equisetum from the Indian Cenozoic.http://www.sciencedirect.com/science/article/pii/S2468265923000215EquisetumFossil stem and leaf sheathsLate MiocenePaleoecologySiwalikWestern India |
| spellingShingle | Sampa Kundu Taposhi Hazra Tapan Chakraborty Subir Bera Mahasin Ali Khan Evidence of the oldest extant vascular plant (horsetails) from the Indian Cenozoic Plant Diversity Equisetum Fossil stem and leaf sheaths Late Miocene Paleoecology Siwalik Western India |
| title | Evidence of the oldest extant vascular plant (horsetails) from the Indian Cenozoic |
| title_full | Evidence of the oldest extant vascular plant (horsetails) from the Indian Cenozoic |
| title_fullStr | Evidence of the oldest extant vascular plant (horsetails) from the Indian Cenozoic |
| title_full_unstemmed | Evidence of the oldest extant vascular plant (horsetails) from the Indian Cenozoic |
| title_short | Evidence of the oldest extant vascular plant (horsetails) from the Indian Cenozoic |
| title_sort | evidence of the oldest extant vascular plant horsetails from the indian cenozoic |
| topic | Equisetum Fossil stem and leaf sheaths Late Miocene Paleoecology Siwalik Western India |
| url | http://www.sciencedirect.com/science/article/pii/S2468265923000215 |
| work_keys_str_mv | AT sampakundu evidenceoftheoldestextantvascularplanthorsetailsfromtheindiancenozoic AT taposhihazra evidenceoftheoldestextantvascularplanthorsetailsfromtheindiancenozoic AT tapanchakraborty evidenceoftheoldestextantvascularplanthorsetailsfromtheindiancenozoic AT subirbera evidenceoftheoldestextantvascularplanthorsetailsfromtheindiancenozoic AT mahasinalikhan evidenceoftheoldestextantvascularplanthorsetailsfromtheindiancenozoic |