Gaurav Srivastava

Birbal Sahni Institute of Palaeosciences · Cenozoic megafossil

The rainforests near the early Eocene palaeo-equator were more resilient to greenhouse warming than mid-latitude vegetation. The mechanism underlying that resilience remains poorly known due to the lack of reliable terrestrial climate data from the palaeo-equator. In this paper, we quantify terrestrial temperature data using a plant proxy approach...

Understanding the evolutionary history of biodiversity hotspots has important implications for their future survival. India hosts four biodiversity hotspots: the Western Ghats of south India, the Andaman and Nicobar Islands, the Eastern Himalaya, and the Indo-Myanmar region. Northeast India (NEI) is an important region that hosts 43% of the total p...

Siwalik sediments were deposited during the Himalayan orogeny in the Himalayan Foreland Basin. They were deposited in a coarsening upward succession to form the Siwalik Group which is further classified into Lower, Middle and Upper Siwalik. These sediments archive abundant plant fossils in the form of wood, leaves, flowers, fruits, seeds and pollen...

A leaf impression of Amesoneuron (Arecaceae) is reported from the Lower Siwalik sediments of the Kankai Mai River section, eastern Nepal. The overall habit, habitat and modern distributions and climatic conditions show the existence of tropical to sub-tropical wet evergreen forests with humid swampy lowland areas during the deposition of the sedime...

The genus Albizia is one of the largest genera in the Fabaceae (the legume family). It is a pantropical genus of ecologically, economically, and chemically important trees, shrubs, and lianas. Fossil records of the genus have been extensively documented from the late Eocene to Pleistocene in Asia. However, no Albizia fossils have been reported from...

During the early Paleogene, greenhouse gases created warm global climates. These warm climates redistributed the habitat of marine and terrestrial biota globally. Understanding the ecology of biotas under extremely warm climates is important to decipher their behavior in future climate warming. Here we report two new legume fossils (Leguminocarpum...

Quantitative Miocene climate and vegetation data from the Siwalik succession of western Nepal indicate that the development of the Indian summer monsoon has had an impact, though in part, on vegetation changes. The climate and vegetation of the Lower (middle Miocene) and Middle (late Miocene–Pliocene) Siwalik successions of Darjeeling, eastern Hima...

Cenozoic plant megafossil records from the eastern part of Nepal are meagre. Here, we report two new fossil leaves, namely Pterygota palaeoalata Srivastava and Mehrotra of the family Malvaceae and Thelypteridaceophyllum tertiarum Joshi and Mehrotra of the family Thelypteridaceae from the Middle Siwalik (late Miocene–early Pliocene) sediments of eas...

Our understanding of the low latitude terrestrial climate of the late Maastrichtian is far from satisfactory. We have attempted to reconstruct the late Maastrichtian vegetation and climate of the Deccan Volcanic Province (DVP), central India. Palaeomagnetic results suggest that the Deccan lava flows were emplaced during the late Maastrichtian C29r...

Neogene fossil records from the Indus Basin sedimentary rocks (IBSR), deposited in the Indus Tsangpo Suture Zone (ITSZ), are very rare, but are important to understand the history of plant diversity and paleoclimate in the Himalaya. We report fossil wood ascribed to Ebenoxylon siwalicus Prakash from late Miocene sediments of the Karit Formation bel...

The existing legume fossil leaves account first report from the lacustrine sediments of intermontane Kathmandu Basin, lying on the southern slope of the central Himalaya. Investigation based on morphological characters and comparison to their nearest living relatives (NRLs) shows closer resemblance to the extant genus of Albizia Durazz. And Bauhini...

Recent paleobotanical investigations in Vietnam provide a good opportunity to improve our understanding of the biodiversity and paleoclimatic conditions in the geological past of Southeast Asia. Palms (Arecaceae) are a diverse family of typical thermophilous plants with a relatively low tolerance for freezing. In this study, we describe well-preser...

Late Oligocene is considered as the last significant globally warm climate. In India, the Makum Coalfield has exposures of sediments which were deposited at a low latitude of 10–15° N during the late Oligocene. Here, we report a diverse assemblage of fossil leaves and fruits. The assemblage envelops 18 leaf and 9 fruit morphotypes. The floristic as...

Today, Northeastern India receives some of the highest annual rainfall totals globally. The major portion of annual precipitation in this region falls during the Indian Summer Monsoon season (June–September); however, this region also receives a significant amount of rainfall during the pre-monsoon season (March–May). Here, we quantitatively recons...

After India separated from Gondwana, its 9000 km northward voyage from the Southern Hemisphere to its modern position joined with Eurasia took 160 million years. During that journey, India experienced a range of climatic conditions due to secular climate variations and its changing latitudinal position. Documenting India's climate during its trans-...

Significance The ancient topography of the Tibetan Plateau and its role in biotic evolution are still poorly understood, mostly due to a lack of fossil evidence. Our discovery of ∼47-Mya plant fossils from a present elevation of 4,850 m in central Tibet, diminishes, significantly, that lack of knowledge. The fossils represent a humid subtropical ve...

Our understanding regarding the onset and development of the modern South Asia monsoon (SAM) is still incomplete due to its complex nature and differing views about its relationship with major orographic features such as the Himalaya and Tibetan Plateau. Climate data derived from some terrestrial and marine sediments from the Neogene suggests the o...

The early Cenozoic was a turning point in the geological history of the Indian subcontinent as it was during this interval that the Indian plate collided with Asia, leading to profound changes in global climates, faunal and floral evolution, orogeny and oceanography. Later Cenozoic records include those from the well known Siwalik successions which...

The Late Paleogene surface height and paleoenvironment for the core area of the Qinghai-Tibetan Plateau (QTP) remain critically unresolved. Here, we report the discovery of the youngest well-preserved fossil palm leaves from Tibet. They were recovered from the Late Paleogene (Chattian), ca. 25.5 ± 0.5 million years, paleolake sediments within the L...

A substantial biotic interchange took place between Gondwanan India and Laurasia immediately following the India-Eurasia collision. Located just north of the collision zone, the role of the Tibetan Plateau in the geographic interchange of biota is still unknown because lack of fossil evidence. Here, well-preserved samara fossils of Ailanthus (the f...

Northeast India is considered as corridor for the plant migration from India to Southeast Asia and vice–versa after the collision of Indian Plate with the Eurasian Plate. The fossil record of the family Lecythidaceae is very sparse globally. We report a fossil leaf of Barringtonia (Lecythidaceae) from the late Oligocene sediments of Assam, India. T...

Arunachal Pradesh, earlier known as NEFA, is the largest among the Seven (now, Eight) Sister States of Notheastern India and most of its parts are covered by the Himalayas. The second Himalayan uplift in the late Oligocene resulted in the development of Main Boundary Fault (MBF) and the Siwalik basin between the rising Himalaya in the north and the...

p>Leaves of Terminalia (Combretaceae) and Daphnogene (Lauraceae) are described from the lower member of Lower Siwalik of Chatara- Barahakshetra area, eastern Nepal. The habit, habitat and present day distribution of the comparable extant taxa indicates the existence of tropical to sub-tropical evergreen to semi evergreen forest with humid climate i...

A fossil wood of Lagerstroemia L. from the Upper Siwalik sediments of Arunachal Pradesh is described. The genus is recorded for the first time from this state. The modern analog of the fossil species i.e. L. tomentosa C. Presl is not found in the fossil locality at present.. The most plausible reason for the disappearance of the species from the fo...

The morning glory family, Convolvulaceae, is globally important in medicine and food crops. The family has worldwide distribution in a variety of habitats; however, its fossil record is very poorly documented. The current fossil record suggests an origin in North America, which is in contrast to molecular data that indicate an East Gondwana origin....

The collision of the Indian and Eurasian plates led to the formation of Himalaya. The uplift of Himalaya had a direct impact on the intensification of South Asian monsoon which has influenced the evolution of many Asian biotas. The plant fossil records from the Indus-Tsangpo-Yarlung Suture Zone are exceptionally significant for the reconstruction o...

We reconstruct climate and vegetation applying the Coexistence Approach (CA) methodology on two palaeofloras recovered from the Lower (middle Miocene; ~ 13–11 Ma) and Middle Siwalik (late Miocene; 9.5–6.8 Ma) sediments of Surai Khola section, Nepal. The reconstructed mean annual temperature (MAT) and cold month mean temperature (CMT) show an increa...

The plant fossil records from the Siwalik Group of Arunachal Pradesh, India are far from satisfactory due to remoteness and dense vegetation of the area. We report seven fossil woods of which three belong to the Middle Siwalik (Subansiri Formation), while the rest are from the Upper Siwalik (Kimin Formation). The modern analogues of the fossils fro...

Plants produce and release a large array of volatile organic compounds that play many ecological functions. These volatile plant metabolites serve as pollinator attractants, herbivore and pathogen repellents and protect plants from abiotic stresses. To date, the geological evolution of these organic compounds remains unknown. The preservation poten...

A leaf of Dipterocarpus (Dipterocarpaceae) is described from the Lower member of Middle Siwalik of eastern Nepal. Its presence indicates that during the deposition of the sediments there was a warm and humid climate with dry season of not more than 3-4 months. The modern distribution of the genus and family reveals that nowadays they have disappear...

Monsoonal climates at low latitudes (< 32°N) are an inevitable consequence of seasonal migrations of the Inter-tropical Convergence Zone (ITCZ), but the character of these monsoons depends on continental configuration, orographic expression and the strength of Hadley circulation. To explore the evolution of monsoon systems across southern Asia we c...

The state of Tripura is inadequately explored as far as the plant remains are concerned. Hence, a fieldwork was undertaken to explore its northern part for building the palaeofloristics and palaeoclimate of the region, and a good number of fossil woods were collected from the Tipam Group (late Miocene) of Laljuri situated near Kumarghat in Unakoti...

Fossil wood was collected from an in situ upright tree encased in the late Oligocene mudstone sediments exposed in the Tirap Mine, Makum Coalfield, tinsukia district, Assam. the wood belongs to Careya of the Lecythidaceae. This genus is reported for the first time from Paleogene sediments. Its presence supports the occurrence of tropical evergreen...

A fossil wood resembling Shorea and other allied genera of the Dipterocarpaceae is described from the Tipam Group of Manipur. This is for the first time any angiosperm wood is recorded from this state. The fossil collected from Jiribam district is considered as late Miocene in age. Its occurrence indicates warm and humid climate in the region durin...

We reconstruct the rise of a segment of the southern flank of the Himalaya-Tibet orogen, to the south of the Lhasa terrane, using a paleoaltimeter based on paleoenthalpy encoded in fossil leaves from two new assemblages in southern Tibet (Liuqu and Qiabulin) and four previously known floras from the Himalaya foreland basin. U-Pb dating of zircons c...

The fossil flora recovered from the Kangvai well, Ratnagiri District, Maharashtra (17°53′41″ N; 73°12′23″ E) has been used to reconstruct the monsoon variations and seasonal rainfall pattern during the Late Pleistocene (44,020 ± 390 years BP) by using the Coexistence Approach. The reconstruction suggests that the Southwest (SW) and Northeast monsoo...

Dilcherocarpon M. C. Singh, R. A. S. Kushwaha, Gaurav Srivastava & R. C. Mehrotra, published in 2012 as a name for a fossil fruit of unknown systematic affinities, is a later homonym of Dilcherocarpon Manchester & E. O'Leary (Combretaceae) and is therefore illegitimate. The new name Davidocarpon Srivastava & Mehrotra is proposed as a replacement na...

AimEarly in their evolution, angiosperms evolved a diversity of leaf form far greater than that of any other group of land plants. Some of this diversity evolved in response to varying climate. Our aim is to test the global relationship between leaf form in woody dicot angiosperms and the climate in which they live.LocationWe have compiled a data s...

Fossil leaves of Lagerstroemia (Lythraceae) are described from the Siwalik deposits (middle Miocene) of Kathgodam, Uttarakhand, India. The fossil records of the Lythraceae indicate its worldwide distribution in the Cenozoic. The family had its widest distribution during the Miocene but became less widespread during the Pliocene, followed by range e...

We describe, in this paper, two fossil leaves preserved in amber for the first time from northeast India. The amber collected from the Thingdawl Hmar Veng quarry belongs to the Upper Bhuban Unit of the Bhuban Formation of Surma Group and is of an early to middle Miocene age. The occurrence of leaf fossils suggest the presence of evergreen forests i...

The coal and carbonaceous shales collected from the Tura Formation (late Palaeocene) of Nangwalbibra, East Garo Hills, Meghalaya, have been analysed for palynological study to deduce palaeovegetation and palaeoclimate. The palynoflora represented by pteridophytic spores and angiospermic pollen grains shows similarity with other contemporaneous depo...

Premise of research: A large number of fossil coryphoid palm wood and fruits have been reported from the Deccan Intertrappean beds of India. We document the oldest well-preserved and very rare costapalmate palm leaves and inflorescence like structures from the same horizon. Methodology: A number of specimens were collected from Maastrichtian–Danian...

Background: The family Phyllanthaceae has a predominantly pantropical distribution. Of its several genera, Bridelia Willd. is of a special interest because it has disjunct equally distributed species in Africa and tropical Asia i.e. 18–20 species in Africa-Madagascar (all endemic) and 18 species in tropical Asia (some shared with Australia). On the...

A fossilised palm fruit of Cocos L. (C. binoriensis sp. nov.) is reported from the Binori Reserve Forest, Ghansor, Seoni District, Madhya Pradesh, India. The fruit is a 3-dimensionally preserved drupe, ovoid with clearly visible longitudinal ridges. The husk is made up of a thin smooth exocarp and fibrous mesocarp, with vertical and horizontal fibr...

The study of the Miocene flora of extra peninsula India is important in order to understand the change in the flora as a result of the upheaval of Himalaya. The Miocene megafossil vegetation of the region is predominantly found in the form of leaf impressions/ compressions, though flowers, fruits and woods are also known. It is known mainly from Ja...

The Miocene flora of peninsular India is of special interest because during this epoch large scale migration of taxa took place from Southeast Asia as a result of the establishment of land connections caused by the suturing of the Indian and Eurasian plates. In order to understand this change in the flora, the study of the Miocene flora of peninsul...

There are many outcrops of the Tertiary sediments in northeast India and a large number of plant megafossils have been described from there. Among all, the Late Oligocene sedimentary basin of Makum Coalfield is very important because there is no other exposure having such a rich palaeofloral assemblage not only from northeast India but also from th...

Mizoram, a state situated in the northeast corner of India, is very rich in fossil woods belonging to the Tipam Group (Late Miocene-Early Pliocene in age). Four new fossil woods, namely Swintonioxylon hailakandiense Prakash & Tripathi, Bombacacioxylon tertiarum Mehrotra et al., gen. et sp. nov., Dipterocarpoxylon jammuense Guleria et al. and Bischo...

An assemblage of fossil leaves is described from the late Oligocene (Chattian 28.1–23 Ma) sediments of Assam, which was located in a low palaeolatitude (∼10–15◦N) during the period of sedimentation. It includes four new fossil leaves resembling Firmiana and Pterygota of the Malvaceae s.l. and Paranephelium and Sapindus of the Sapindaceae. The prese...

A fossil leaf resembling Poeciloneuron indicum Bedd. (Clusiaceae) is described from the Late Oligocene (Chattian 28.4–23 Myr) sediments of Assam. The modern analogue is endemic to the Western Ghats which is situated in the same palaeolatitude. Its presence, along with other known fossil records, indicates that the seasonality in temperature was les...

A new fossil leaf impression of Alphonsea Hk. f. & T. of the family Annonaceae is described from the Late Oligocene sediments of Makum Coalfield, Assam, India. This is the first authentic record of the fossil of Alphonsea from the Tertiary rocks of South Asia. The Late Oligocene was the time of the last significant globally warm climate and the fos...

Climate Leaf Analysis Multivariate Program (CLAMP) is a versatile technique for obtaining quantitative estimates for multiple terrestrial palaeoclimate variables from woody dicot leaf assemblages. To date it has been most widely applied to the Late Cretaceous and Tertiary of the mid- to high latitudes because of concerns over the relative dearth of...

Eleven fossil woods belonging to seven families are described from a petrified wood forest of Mizoram. This fossil assemblage is derived from sediments belonging to the Tipam Group considered to be Late Miocene–Early Pliocene in age. The modern counterparts of the identified taxa are: Gluta L., Mangifera L. (Anacardiaceae), Bursera Jacq. ex L. (Bur...

The fossil megaflora, from the late Oligocene deltaic sediments exposed in the Tirap coal mine, Assam, India (27° 17′ 20″ N, 95° 46′ 15″ E), laid down at a palaeolatitude of 10–15° N, records the composition and climate of tropical vegetation during the last episode of pronounced global warmth before the progressive overall cooling to present day c...

The sedimentology, palynofacies and pollen and spore assemblages, together with observations on the preserved megaflora, from the Tirap coal mine, Assam, India (27° 17′ 20″ N, 95° 46′ 15″ E) provide important insights into the composition and distribution of plant communities in a late Oligocene tropical delta (palaeolatitude approximately 18°N). T...

Some plant remains are described from the Laisong Formation (Barail Group) of Thoubal and Senapati districts of Manipur. The flora is diverse comprising gymnospermous, monocotyledonous and dicotyledonous forms and indicates tropical to subtropical climate in the vicinity of the area during the deposition of the host rocks.

Pterospermumocarpon (Type: P. kalviwadiensis), a new morphogenus of fossil fruits showing resemblance with fruits of extant Pterospermum Schreb. (Malvaceae s.l.), is described from the Sindhudurg Formation (Miocene) at the Kalviwadi Village, Sindhudurg District, Maharashtra, India. Diagnostic feature of the fossil taxon is the dehiscent pentalocula...

Two new palm leaf impressions, cf. Iguanura wallichiana and Palmacites makumensis sp. nov. are described from the Makum Coalfield, Tinsukia District, Assam. They belong to the Tikak Parbat Formation being considered as Late Oligocene (Chattian 28–23 Myr) in age. Their presence, along with the other known fossil records indicates that CMMT (cold mon...

Plant fossils, mainly leaf impressions, are described for the first time from the Tipam Group of rocks exposed at Subankhata Locality in Manas National Park in Baksa District of Assam. Two new fossil leaves showing affinities with Parashorea stellata Kurz and Shorea ovalis (Korth.) Bl. respectively of the family Dipterocarpaceae, along with a fern...

In order to reconstruct the palaeoclimate, a number of fossil wood pieces were collected and investigated from two new fossil localities situated in the Dhemaji and Lakhimpur districts of Assam. They belong to the Tipam Group considered to be of Middle–Late Miocene in age and show affinities with Gluta (Anacardiaceae), Bischofia (Euphorbiaceae), Ba...

A new fossil leaf impression is described from the Early Miocene sediments of Kasauli–Kalka road section, Himachal Pradesh. The characteristic leaf venation pattern suggests that it has a close affinity with Ficus L., particularly with F. racemosa L. (= F. glomerata Roxb.). Its presence indicates a warm and humid climate in the region during the de...