Subir Bera

• M.Sc., M.Phil., Ph. D.
• Professor at University of Calcutta

This study explores the significant role of non-conventional pollinators in the pollination of ten cucurbit crop species in deltaic Bengal, India. While traditional pollinators such as bees, butterflies, and moths are well-documented, this research highlights the overlooked contribution of insects, typically considered pests or predators. The field...

Although modern members of Zygosporium are reported on a wide range of monocotyledons, the fossil record of this hyphomycetous fungus on monocots is rather poor. Here, we document the occurrence of Zygosporium fossils in appreciable numbers on the cuticular fragments of compressed monocot leaves preserved in Late Miocene Middle Siwalik sediments of...

To develop a phytolith (biogenic silica) reference and to understand the eco-climatic indicative values of some grass silica short cells (GSSCs) occurring in the bamboos (Bambusoideae grasses), one of the chief floral components of eastern and north-eastern parts of India, we studied 44 modern bambusoid grasses and 26 surface soils from different e...

Extrafloral nectary-mediated ant pollination in cucurbit crops during monsoon in deltaic Bengal, India

Phytolith analysis is a powerful tool in taxonomic, ecological, and paleoenvironmental studies due to the durability and diagnostic potential of these microscopic silica bodies. This study investigates the variability of phytoliths in four Sporobolus species (Sporobolus diander, Sporobolus spicatus, Sporobolus tremulus, and Sporobolus wallichii) fr...

Ants are considered to be necter thieves and usually do not take part in the pollination process directly. We have Studied the extrafloral nectary mediated interaction of ants with cucurbit crops(Luffa acutangula, Luffa cylindrica, Cucurbita moschata, Momordica charantia, Trichosanthes cucumerina, Lagenaria siceraria, Coccinia grandis, Benincasa hi...

Archaeobotany deals with the interpretation of preserved plant remains from the archaeological sites in order to reconstruct the past vegetation and climate change and past human-plant relationship. The archaeobotanical remains found in the archaeological sites are classified into two groups; macro and microbotanical remains. Usually, the microbota...

In Sunderbans Delta, West Bengal, a good number of phloem sap-feeding fauna is found dependent on wild date palm Phoenix sylvestris (L.) Roxb. for their sustenance. Phoenix sylvestris (L.) Roxb., a hardy palm species found in various regions of the world, stands as a testament to the intricate web of life that exists within ecosystems through phloe...

We report a new type of fossil margin galls arranged in a linear series on dicot leaf impressions from the latest Neogene (Pliocene) sediments of the Chotanagpur Plateau, Jharkhand, eastern India. We collected ca. 1500 impression and compression leaf fossils, of which 1080 samples bear arthropod damage referable to 37 different damage types (DT) in...

INTRODUCTION Pollination is a significant natural process making progress in understanding the interactions between plants and their pollinators when pollinators play a crucial role in reproduction of flowering plants and in the production of most fruits and vegetables. Coriandrum sativum L. usually depend on pollinators during fruit and seed setti...

Equisetum L. (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 fr...

Pollination is an important ecological phenomenon where life exists and grows. Insects are the most important pollinators of plants. From plants, people get food, medicines, and other life stuff, which are actual results of pollination. Among the plant species, the edible and medicinal plants of the Cucurbitaceae family are the most common and olde...

The Ventilago Gaertn. (Rhamnaceae) is widely distributed in pantropical areas of Africa, Asia, and Australia. However, fossil records of this taxon are sparse, which limits understanding of the evolution and biogeographic history of the genus. In the present study, we report and describe two new fossil species of Ventilago, V. siwalika sp. nov. fro...

The intra-seasonal variation in precipitation isotopes shows a characteristic declining trend over northeast India. As of now, no mechanism offers a consistent explanation of this trend. We have performed the isotopic analysis of precipitation (rain) and estimated net ecosystem exchange and latent heat fluxes using an eddy-covariance system in nort...

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 docu...

The mechanism of protein degradation has remained a topic of debate (specifically concerning their preservation in deep time), which has recently been invigorated due to multiple published reports of preservation ranging from Miocene to the Triassic that potentially challenge the convention that protein preservation beyond the Cenozoic is extremely...

We combine phytoliths, non-pollen palynomorphs, stable carbon isotopes of sediment organic matter, environmental magnetic parameters and sediment texture data of a lacustrine sedimentary archive from the Bengal region to understand the ecosystem response to past hydroclimatic changes. The region experienced a high Indian summer monsoon (ISM) rainfa...

Zygosporium Mont. (Zygosporiaceae, Xylariales, Sordariomycetes) is known to have saprophytic or parasitic relationship with various modern angiosperms. Fossil record of such an interaction is unknown till date. Here, we report in situ occurrence of asexual morphs of two fossil species of Zygosporium from the Neogene Siwalik sedimentary strata of ea...

The oldest undisputed fungal fossils date back to the Ordovician, yet display a large diversity and possess noticeable organizational development. On the other hand, molecular clock studies estimate the separation of the fungal clade from basal metazoans during the Cryogenian (Berbee and Taylor, 2010). Some recent studies (Loron et al., 2019; Bonne...

A monolete spore from the upper Permian Raniganj Formation strata of the Madhukunda area in the Damodar Basin is described as Ghoshiasporites manjuae sp. nov. It is laevigate proximally but has a variable densely apiculate ornamentation distally, prompting its classification in the Subinfraturma Varimonoleti and Infraturma Sculptatomonoleti. The di...

Abstract Reliability of grass phytoliths for discriminating different deltaic sub-environments has been assessed on the modern surface sediments collected along the salinity gradient of the Sunderbans delta, India. It has been observed that grass phytolith assemblages can successfully distinguish different deltaic sub- environments especially the...

ABSTRACT: The present study deals with the folk-culture and biodiversity sources and conservation practices in Sundarban Region (WB), India. Almost 19 police stations and community development blocks were taken for this case study. An intensive anthropological field work was carried out with the interview of senior people of study region where we h...

The present study deals with the folk-culture and biodiversity sources and conservation practices in Sundarban Region (WB), India. Almost 19 police stations and community development blocks were taken for this case study. An intensive anthropological field work was carried out with the interview of senior people of study region where we have doc...

Here, we report the in-situ occurrence of a new fossil-species of Meliolinites (fossil Meliolaceae), Meliolinites bhutanensis sp. nov. on the cuticle fragments of a compressed angiosperm dicot leaf recovered from the middle Siwalik (Formation II: latest Miocene to Pliocene) of Bhutan, eastern Himalaya. This unique foliicolous new fossil fungal spec...

Phytolith analysis of grasses is a potential tool in taxonomic, environmental as well as palaeoecological studies. Development of regional grass phytolith reference collection is a prerequisite and extremely crucial for proper utilization of grass phytolith as an effective proxy. During a comprehensive phytolith study from grasses of lower Gangetic...

Lamiaceae Martinov, is the sixth largest angiosperm family and the largest within the order Lamiales, comprising of over 230 genera and more than 7000 species worldwide (Harley et al., 2004; Olmstead, 2016; APG IV, 2016). In flora of India, the family is one of the ten largest families represented by 67 genera and 399 species (Sampath Kumar et al.,...

Plants and insects are essential components of terrestrial ecosystems and insect herbivory is the most important type of biotic interaction in these ecosystems alongside the role of insects as pollinators. Insect damaged fossil leaves are the only direct sources of documenting the historical effect of folivorous arthropods on once living foliar tis...

Thespesia populnea (L) Sol. ex Corrêa (Malvaceae), known as the Indian tulip tree, is a well-known fast-growing, economically and ecologically important evergreen species in the tropical forests of India. However, no reliable fossil evidence of Thespesia has been reported from the Cenozoic sediments of India so far. Here, we document for the first...

Fungivory, most commonly in combination with saprophagy and xylophagy, is characteristic of many families of coleopteran beetles and ants. Fungi and Coleoptera are among the most evolutionarily successful and diverse heterotrophic organisms in the ecosystem. Due to their unique adaptive traits, fungi and beetles co-exist and interact in various way...

Ten palm leaf impressions are documented from the latest Maastrichtian (late Cretaceous) to early Danian (earliest Paleocene) sediments (K-Pg, c. 66–64 Ma) of the Mandla Lobe of the Deccan Inter-trappean Beds, Madhya Pradesh, central India. The palmate leaf shape along with a definite well-preserved costa support their placement in the subfamily Co...

Due to several overlaps of the primary pollen morphological attributes (viz., aperture type and exine sculpturing) throughout the subfamilies and tribes of Rubiaceae, they are of less importance in delineating majority of the taxa at the subfamilial and tribal levels than at generic and specific levels. This in turn renders difficulties in the iden...

The present study reports in situ occurrence of species of Phomites, a fossil epiphyllous fungus (comparable to cosmopolitan filamentous modern plant pathogen Phoma Sacc.), on the cuticular surface of fossilized leaf fragments of different compressed angiosperm leaf remains recovered from the Siwalik sediments (middle Miocene to early Pleistocene)...

Although dicot megafossils are well-known from Siwalik sediments of India, the record of monocot fossils during the Siwalik period is rather poor. The present study highlights, for the first time, the recovery of a large number of monocot leaf remains from the middle Siwalik sediments (late Miocene) of Himachal Pradesh, western Himalaya. The diagno...

Plant–insect interactions in the fossil record are, as yet, sparsely known and understudied. Here, we document evidence of a new type of insect skeletonization on Abroma augustum (L.) L. f. (Malvaceae) leaf remains from the latest Neogene (Pliocene) sediments of Chotanagpur plateau, Jharkhand, eastern India. This unique skeletonization feeding trac...

Reliability of grass phytoliths for discriminating different deltaic sub-environments has been assessed on the modern surface sediments collected along the salinity gradient of the Sunderbans delta, India. It has been observed that grass phytolith assemblages can successfully distinguish different deltaic sub-environments especially the true mangro...

Indian Cenozoic deposits contain well-preserved diverse angiosperm leaf assemblages, but galling, a common form of angiosperm leaf damage in modern tropical forests, has not been well-documented. Here we report insect herbivory on diverse angiosperm fossil leaf specimens from Pliocene (Rajdanda Formation) sediments of the Chotanagpur Plateau, easte...

Evidence of predatory marks on fossil leaf remains provides a unique window into ecological and evolutionary associations of the past, but finding both damage and the phytophagous insects causing that damage pattern in the same fossil specimen is a very rare phenomenon. Normally, caterpillars have little fossilization potential because of their del...

We report for the first time well-preserved leaflets of Hylodesmum palaeoglutinosum from the latest Neogene sediments (Rajdanda Formation: Pliocene) of Jharkhand, eastern India. Macromorphological features show that the fossil leaflet remains are identical to those of modern endemic taxon H. glutinosum (Muhl. ex Wild.) Ohashi & Mill (tribe: Desmodi...

Phytolith assemblages of Shorea robusta Gaertn. (Dipterocarpaceae), an important constituent of tropical deciduous/semi-evergreen forests were studied from six different districts of West Bengal, the western margin of the Bengal Basin. Since S. robusta grows in the tropical mixed dry to wet deciduous and semi-evergreen forests and can tolerate a wi...

Peltophorum (Caesalpinioideae: Fabaceae) is a well-known extant legume genus characterized by marginally bi-winged fruits. No reliable fossils of Peltophorum have been reported previously. Here, we report for the first time well-substantiated fossil fruits of Peltophorum exhibiting an oblong to narrowly elliptic fruit body with longitudinal wings a...

Porteresia coarctata (Roxb.) Tateoka is a true halophytic perennial wild grass that grows profusely along newly formed, highly saline landmasses and mudflats in the coastal mangroves of the Indian subcontinent and acts as a pioneer species in mangrove succession. Comprehensive phytolith analyses on sixteen P. coarctata samples collected from differ...

Integration of palaeobotanical (spores, pollen, phytoliths and non-pollen palynomorphs) and organic geochemical proxies, such as stable isotopes of organic carbon (δ ¹³ C) and n-alkanes, for studying the evolution and palaeoenvironmental conditions of an archaeological site are rare in India. The evolution of a protohistoric-historic site at Erenda...

Although Asia shows moderate species richness of mulberry (Morus L.) today, unfortunately no mulberry fossil has been reported from the Cenozoic sediments of this continent to date. Here, we report for the first time the occurrence of leaf remains (both impression and compression) having similarity with modern leaves of Morus from the early Eocene...

Fabaceae, presently a significant dominant taxon of the tropical vegetation of India, has been recognized as the most widespread and common component of Indian Cenozoic flora and known from numerous fossil woods, leaflets, pollen, and fruits. However, unfortunately no fossil legume flower has been reported from the Cenozoic sediments of India so fa...

Albizia, a diverse tree genus, occupies monsoonal warm, humid rain forests in tropical and subtropical regions. We recovered a well-preserved compound fossil leaf and two fossil fruits of Albizia (Fabaceae) from the latest Neogene (Rajdanda Formation: Pliocene) sediments of Jharkhand of Chotanagpur Plateau, eastern India. On the basis of the archit...

Although presently indigenous to eastern Himalaya in India, no Engelhardioideae have been reported from the Cenozoic sediments of India till date. Here, we report the first Indian occurrence of a characteristic engelhardioid winged samaroid fruit having a tri‐lobed wing (oblong‐ovate shaped median lobe and two lateral lobes) and a globose nut from...

Detailed pollen morphological account of four species of Maesa Forssk. (Primulaceae) [M. chisia, M. indica, M. macrophylla, M. rugosa] from Darjeeling Himalaya and its possible taxonomic implications have been investigated using light (LM) and scanning electron microscopy (SEM). The pollen grains are 3-zonocolporate with reticulate exine having pro...

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-...

To assess the pattern of climatic evolution during the late Miocene to early Pleistocene in the largest fluvio-deltaic sedimentary system on the Earth, the Bengal Basin (BB), a quantitative palaeoclimatic reconstruction was made, based on 20 fossil wood floras. Those floras show that moisture-loving taxa have decreased considerably since the Miocen...

Dipterocarpaceae, a tropical plant family that forms a major component of low-lying rainforests in Southeast Asia, is represented by a large number of fossils from the Cenozoic sedimentary successions of India, but the origin and antiquity of this family has been actively debated. The earliest reliable dipterocarp megafossils so far reported in Ind...

Here, we describe a new impressed palm frond from the latest Maastrichtian (late Cretaceous)-earliest Danian (early Palaeocene) sediments of the Deccan Intertrappean beds of Madhya Pradesh, Central India. The diagnostic characters of the recovered fossil specimen are large palmate fan-shaped leaf with well-preserved long costa (costapalmate), plica...

Terminalia arjuna (Roxb.) Wight & Arn., a large evergreen tree, shows massive flowering during spring season (March–April). The floral characteristics with deep seated nectar having high sugar concentration serve this plant as an important pollen and nectar source for Apis bees. The inflorescences with clusters of flowers of this plant provide an e...

A well-preserved fossil dragonfly (Odonata: Anisoptera) recovered from the late Neogene sediments of the Chotanagpur plateau, Jharkhand, eastern India.

Past climate reconstructions from palaeoecological records require an understanding of relationships between modern vegetation and climate. Phytoliths are being used widely to reconstruct variations in C3/C4 grasses in the past vegetation and corresponding climate. However, little understanding is available on their relationships with the climate d...

Past climate reconstructions from palaeoecological records require an understanding of relationships between modern vegetation and climate. Phytoliths are being used widely to reconstruct variations in C3/C4 grasses in the past vegetation and corresponding climate. However, little understanding is available on their relationships with the climate d...

Here we study a well-preserved petrified palm stem from the latest Maastrichtian (Late Cretaceous) to earliest Danian (early Paleocene) sediments (c. 66-65 Ma old) of the Deccan Intertrappean Beds of Madhya Pradesh, Central India. We infer its systematic relationships and relevance to palm evolution. The significant anatomical attributes of the fos...

A compressed fossil fish bearing close resemblance to sub-family Leuciscinae (family: Cyprinidae) is reported from latest Neogene (?Pliocene) sediments of Chotanagpur plateau, eastern India. The recovered fossil fish contains exceptionally well-preserved skeleton. It is characterized by compressed belly, medium-sized head, well-preserved skull, ten...

Silicified fossil legume woods of Cynometroxylon Chowdhury & Ghosh collected from the Neogene (late Miocene) sediments of the Bengal Basin, eastern India, exhibit fungal decay seldom found in the fossil record. The wood possesses numerous perforate areas on the surface that seem to be the result of extensive fungal activity. In transverse section,...

Silicified fossil legume woods of Cynometroxylon Chowdhury & Ghosh collected from the Neogene (late Miocene) sediments of the Bengal Basin, eastern India, exhibit fungal decay seldom found in the fossil record. The wood possesses numerous perforate areas on the surface that seem to be the result of extensive fungal activity. In transverse section,...

In situ preservation of fossil insect damage in plant fossils is an excellent tool to study the coevolution of flora and fauna through geological time, but finding both damage and the insect causing that damage in the same specimen is a very rare phenomenon. Galling is a common form of angiosperm leaf damage, which can be regarded as a kind of exte...

A unique kind of fern-insect interaction in the paddy fields of West Bengal, India is described. The interaction was recorded between the floating fern Azolla pinnata R. Br. and a lepidopteran Elophila obliteralis Walker. Azolla balls were found to be floated in the paddy field. Larval phases of the insect made oval 'case' like structures primarily...

The collision between the Indian and Asian plates during Cenozoic resulted in the creation of a peripheral foreland basin occurring all along the southern flank of the Himalaya. In this chapter, the broad tectonic framework, chronostratigraphy, climate, dispersal pattern, depositional systems and large-scale paleogeography of the foreland basin are...

A fossil leaf assemblage from latest Neogene (Pliocene) sediments exposed in Jharkhand of Chotonagpur Plateau, eastern India, is subjected to a CLAMP (Climate Leaf Analysis Multivariate Program) analysis using a new high spatial resolution (~1 km2) WorldClim2 gridded climate data and PhysgAsia2 calibration. The CLAMP analysis of 80 different morpho...

Collagens are the most abundant proteins in the animal kingdom. They form the structural framework of connective tissues such as bones, tendons and skin, and play important biomechanical role in supporting tissue functions. The preservation of collagen in deep time is a topic of intense debate. Here we provide indisputable evidence for the presence...

A new petrified palm stem Palmoxylon dindoriensis Khan, Roy et Bera, sp. nov. from the latest Maastrichtian (late Cretaceous)-earliest Danian (early Paleocene) sediments of the Deccan Intertrappean beds of Madhya Pradesh, central India is reported. Sections from different parts of the recovered stem were prepared by using standard thin section tech...

Polar transport of the phytohormone auxin is a well-known physiological phenomenon recorded in different extant plant groups including bryophytes and pteridophytes. Earlier, this phenomenon has been recorded in an Upper Devonian (375 million-year) arborescent progymnosperm, Archaeopteris. Since then further record of such occurrence of polar auxin...

Two hitherto unexplored settlements at Karim Shahi and Vigakot are reported from the uninhabited hyper-arid region of the western Great Rann of Kachchh (GRK), located near southern fringe of Thar Desert, Gujarat, NW India. The archaeological evidence, supported by radiocarbon and optical chronology indicate presence of settlement from the Early Iro...

We report here the occurrence of petrified wood resembling the modern dipterocarp Dryobalanops from the Neogene (late Miocene) of the Bengal Basin, India. We have determined the taxonomic position by comparing its anatomical features with similar extant and fossil specimens and have finally identified this late Miocene wood as Dryobalanoxylon neosu...

CenozoicHimalayan foreland basin: an overview and regional perspective of the evolving sedimentary succession Tapan Chakraborty1*, Suchana Taral1, Sandip More2, Subir Bera2 1Geological Studies Unit, Indian Statistical Institute, Kolkata 700108 2Center of Advanced Study, Department of Botany, University of Calcutta, Kolkata, 700019 *corresponding au...

The pollen morphology of seven species of the genus Bauhinia L. (Leguminosae: Caesalpinioidae) namely Bauhinia acuminate L., B. malabarica Roxb., B. purpurea L., B. scandens L., B. tomentosa L., B. vahlii Wight & Arn. and B. variegata L. from the sub-Himalayan Terai-Duars region of West Bengal was examined with light and scanning electron microscop...

We report the in situ occurrence of a new species of Meliolinites (fossil Meliolaceae, Ascomycota), Meliolinites pliocenicus, on the lower epidermal surface of fossilized angiosperm leaf of Shorea siwalika (Dipterocarpaceae) recovered from the middle Siwalik stratum (Subansiri Formation: Pliocene) of Arunachal sub-Himalaya. This fungal morph is cha...

We report in this article, the in situ occurrence of a new species of Meliolinites (fossil Meliolaceae), Meliolinites neogenicus sp. nov. on the abaxial cuticular surface of fossilized leaf cuticle fragments of the angiosperm Litsea cf. salicifolia Khan et al. (Lauraceae) recovered from the upper part of the Siwalik succession of Neogene sediments...

A new species of permineralized palm stem, Palmoxylon deoriensis Khan, Mandal et Bera, sp. nov. is described from the Late Maastrichtian (late Cretaceous) – Danian (early Paleocene) sediments of the Deccan Intertrappean Beds of Deori village in Dindori District, Madhya Pradesh, Central India. The fossil specimen is a stem, characterized by the pres...

To study the atmospheric moisture transport processes from the source to a receiver region, isotopic analysis of rainwater from Port Blair (as source region), the Andaman Islands, Bay of Bengal has been carried out. In addition to the island site, rainwater collected at three sites on the Indian mainland (as receiver region) namely Nagpur, Kolkata,...