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Morphotaxonomical study on the plant fossils (leaf and fruit impressions) collected from Lower Siwalik sediments of Tanakpur area, Uttarakhand revealed the occurrence of 57 species of 25 angiospermous families. Of these, 39 species have been recorded new to the fossil flora of Himalayan foot hills and remaining 18 species are reported already from...
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Context 1
... Siwalik Group has been subdivided into Lower, Middle and Upper Siwalik (Pilgrim, 1913). The Siwalik deposits are one of the most comprehensively studied fluvial sequences in the world. They comprise mudstones, sandstones and coarsely bedded conglomerates laid down when the region was a vast basin during Middle Miocene to Upper Pleistocene times (Fig. 2). In the broadest sense, the rocks become coarser grained upward through the Group being dominated by claystone, mudstone and siltstone in the lower part and terminating with conglomerates beds in the uppermost units. The sediments were deposited by rivers flowing southwards from the Greater Himalayas, resulting in extensive ...
Context 2
... strongly indicate their resemblance with the modern leaves of the genus Palaquium Blanco. of the family Sapotaceae. A critical study of the herbarium sheets of this genus shows that the leaves of Plaquium grandis (Thwaites) Engl. (Syn. Dichopsis grandis (Thwaites) C.B. Clarke in shape, size and venation pattern (C.N.H. Herbarium Sheet No. 280694; Pl. 22.2, ...
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... has formulated an equation to estimate the MAP by using the proportion of large size leaves in the assemblage of any region. This equation is as follows: MAP = 47.5 + 6.18X (% Large leaves) (% Large leaves) is the percentage of leaves in an assemblage of mesophyll size or larger in area (≥ 33 cm 2 ). ...
Citations
... • Annonaceae family is reported in Mahakali River (Tanakpur) section (Shashi et al. 2006(Shashi et al. , 2008Prasad et al. 2017b), Godavari section (Sah et al. 2000), Arjun Khola section (Gautam 2017;Prasad et al. , 2018Prasad et al. , 2019, Koilabas section (Prasad et al. 1997a(Prasad et al. , 1999Tripathi et al. 2002;Prasad and Dwivedi 2008;Chandra and Tripathi 2021a), Surai Khola section (Awasthi and Prasad 1990;Prasad and Awasthi 1996), and Tinau Khola and Arung Khola sections (Konomatsu and Awasthi 1999). • Burseraceae family in Mahakali River (Tanakpur) section (Shashi et al. 2008) and Arjun Khola section (Gautam 2017;Prasad et al. 2019). ...
... • Burseraceae family in Mahakali River (Tanakpur) section (Shashi et al. 2008) and Arjun Khola section (Gautam 2017;Prasad et al. 2019). • Combretaceae family in Mahakali River (Tanakpur) section (Prasad et al. 2017b), Arjun Khola section (Gautam 2017;Prasad et al. , 2019, Koilabas section (Tripathi and Tiwari 1983;Prasad and Prakash 1984;Prasad 1990aPrasad , 1994, Surai Khola section (Awasthi and Prasad, 1990), and Chatara-Barahakshetra section (Adhikari 2017;Adhikari et al. 2018). • Clusiaceae family in Mahakali River (Tanakpur) section (Prasad et al. 2017a, b), Arjun Khola section (Gautam 2017;Prasad et al. , 2019, Koilabas section (Prasad 1994;Prasad et al. 1999), Surai Khola section (Awasthi and Prasad 1990;Prasad and Awasthi 1996;Prasad and Pandey 2008), and Tinau Khola and Arung Khola section (Konomatsu and Awasthi 1996). ...
... • Clusiaceae family in Mahakali River (Tanakpur) section (Prasad et al. 2017a, b), Arjun Khola section (Gautam 2017;Prasad et al. , 2019, Koilabas section (Prasad 1994;Prasad et al. 1999), Surai Khola section (Awasthi and Prasad 1990;Prasad and Awasthi 1996;Prasad and Pandey 2008), and Tinau Khola and Arung Khola section (Konomatsu and Awasthi 1996). • Myristicaceae family in Mahakali River (Tanakpur) section (Prasad et al. 2017b) and Surai Khola section (Awasthi and Prasad 1990). ...
Floral taxa from the middle Miocene to the early Pleistocene have been thoroughly documented in the Siwalik sediments in the Nepal Himalayas and are well recorded from 1983–2022. In the present article, we attempted to compile the information about the paleofloristic and paleoclimate changes during the middle Miocene to early Pleistocene period and compile the information related to plant remains recorded so far throughout the Neogene period. The Siwalik Group contains a total of 434 species, comprising 180 genera of 53 families of ferns and angiosperm megafossils and 459 species belonging to 84 families of gymnosperms, angiosperms, pteridophytes, and algal and fungal palynofloral fossils. Due to the fact that palynomorphs have deformed and distorted surface ornamentation and aperture arrangements, most species can only be recognized at the family level. Most of the fossilized families and taxa still exist in the area where the fossils were found. However, some of them, like Calophyllum polyanthum, Dipterocarpus, Cinnamomum tavoyanum, and Filicium decipiens, have disappeared because of changes in rainfall and temperature seasonality after the rise of the Himalayas. Based on the reconstructed climate data, the distribution pattern of fossil assemblages looks more or less similar in most of the Siwalik Group. However, there are still some gaps in our knowledge about how the floral assemblages in the eastern and far-western parts of Nepal changed and developed over time. The overall fossil assemblages of the Siwalik Group suggest that there were tropical and subtropical evergreen rain forests with warm and humid climates that received high rainfall. The plant fossils also suggest that the vegetation shifts occurred due to changes in regional aridification and temperature seasonality.
... Additionally, there is L. siwalika from Lower Siwalik of Koilabas, western Nepal (Prasad, 1994a) and Neyveli Lignite Mine-1, South Arcot district, Tamil Nadu (Agarwal, 2002). The fossil leaves L. mioparvifolia and L. eomicrocarpa (Dwivedi et al., 2006) were found in Siwalik sediments of the Koilabas area in western Nepal, while L. mioparvifolia Dwivedi et al. and L. prakashii were discovered in the Lower Siwalik of Tanakpur, Uttrakhand (Prasad et al., 2017). L. imamurae Tanai and Uemura (1991) was found in the Oligocene of Honshu, Japan, and L. corvinusii was reported in the Middle Churia Formation, Arjun Khola, western Nepal (Prasad, 2013). ...
Palaeobotanical investigations were conducted on plant macrofossils obtained from the Middle Siwalik sediments of Sarkaghat, Mandi District, Himachal Pradesh, India as part of this current communication. This study discovered the existence of two previously unknown fossil species that correspond to the taxa that are now living, Lagerstroemia Linn. and Millettia Wight & Arn. of the families Lythraceae and Fabaceae, respectively. These modern comparable taxa of the macrofossils reported here are distributed in the tropical evergreen to moist deciduous forests of the southeast Asian region which may suggest that tropical forests under moist conditions were prevalent during the Upper Miocene times in this region in contrast to mixed deciduous forest under the reduced precipitation at present. It also indicates the prevalence of a humid tropical climate during the Miocene in the Sarkaghat area.
... Of these four species are described from the Siwalik sediments of India and Nepal. These are Randia miowallichii from Siwalik sediments of Koilabas, western Nepal and from Oodlabari, Derjeeling District, West Bengal, India (Antal & Awasthi, 1993), R. siwalica and R. palaeofasciculata from Siwalik sediments of Suraikhola, western Nepal and R. miouncaria Prasad & Diwvedi (2007) from the Siwalik sediments of Serianaka, Koilabas area, western Nepal and R. tanakpurensis Prasad et al. (2017) from the Siwalik sediments of Tanakpur area, Uttarakhand. ...
Qualitative and quantitative analysis of fossil assemblage so for recovered from
the Middle Siwalik sediments of Darjeeling district,West Bengal revealed the
occurrence of 35 new taxa belonging to 18 angiospermous families. On the basis
of present data as well as already known data from there, the reconstruction of
vegetation scenarios of Himalayan foot hills during Siwalik time has been done
and also discussed on problems related to plant diversity, endemism, and
migratory pathways of mainly phytogeograpraphically important taxa. The
analysis of present day distribution of all the recovered taxa from the region
shows that they are mostly known to occur in Northeast India, Bangladesh,
Myanmar and Malayan region wherever favourable climatic conditions are
available. About 1/3 taxa of total assemblage found to grow presently in the
Himalayan foot hills of the eastern region and remaining 2/3 taxa are locally
extinct. This indicates that the climatic changes must have taken place after MioPiocene, times. The dominance of evergreen elements in present fossils
assemblage indicates the prevalence of tropical warm humid climate with plenty
of rainfall during the deposition of sediments. Foliar physiognomic approach for
reconstruction of palaeoclimate further suggests that the Oodlabari area in the
Himalayan foot-hills of West Bengal enjoyed a tropical climate (with MAT 28.90C
and MAP 448mm) during the Miocene period. This is, however, contrary to the
present day climate of the area with reduced precipitation.
On the basis of present fossil assemblage, the Coexistence intervals of different
climatic parameter ie. Mean annual temperature (MAT), Wormest month
temperature (WMT), Coldest month temperature (CMT), and Mean annual
precipitation (MAP) have been estimated as 220C-26.50C, 17.80C -200C, 250C, 300C, and 2650mm-3200mm respectively. The other approach, Leaf margin
analysis (LMA) suggests the MAT value as 28.90C for the area during Upper
Miocene times.
... The Churia Zone has number of east-west running thrusts. The Churia sediment is characterized by alternate presence of sand stone and mud stone facies, the later very often containing abundant plant fossils belonging to both Monocotyledonous and Dicotyledonous families [2][3][4][5]. ...
... So far, there is only one record of fossil leaves of the genus Drimycarpus Hook f. as D. siwalicus from the Siwalik sediments of Tanakpur area, Uttarakhand, India (Prasad et al., 2017). The comparative study shows that the above siwalik fossil is narrow (4.2cm in width) and the intersecondary veins are not seen in it. ...
Dalbergia is a pantropical genus of Fabaceae with a limited fossil record. In this study we describe diverse and well-preserved Dalbergia fossils distributed through Cenozoic (Eocene to Pliocene) strata in Yunnan Province, Southwest China. Comparison with newly collected modern samples from Eurasian forests and herbarium specimens allow accurate identification of our fossil materials, and we demonstrate that Yunnan Province represents an hitherto unrecognised hotspot for the diversification of Dalbergia. Our findings also include evidence of the earliest known mining damage reported on Dalbergia leaflets, which sheds light on their interactions with various arthropods (Leucoptera and other insects) during the early Neogene. As such, our results improve knowledge of Dalbergia fossils in East Asia and are crucial for understanding the evolutionary history of analogous mining behavior observed from modern Dalbergia.
In the present investigation, a morpho-taxonomic study has been carried out on recently recovered plant macrofossils from the Siwalik Group (Middle Miocene) sediments of Sarkaghat, Mandi District, Himachal Pradesh, India. This has revealed the occurrence of two new fossil leaves belonging to the extant taxa, Artocarpus heterophyllus Lam. and Phoebe opaca Blume. of the tropical dicotyledonous families, Artocarpaceae and Lauraceae respectively. As the nearest living relatives of the macrofossils reported here, are restricted to the southern part of India and southeastern Asia (Sri Lanka, Malaya, Indonesia, and Philippines), it is plausible that tropical forests under moist conditions were prevalent during the Upper Miocene times in this region. The recovered data also indicates prevalence of tropical climatic conditions during the Miocene in the Sarkaghat and nearby area.
