First Discovery of the Earliest Angiospermous Megafossils in the World

The first discovery of the earliest angiospermous megafossils, so far in the world,was made by the authors from the Lower Cretaceous Chengzihe Formation of Jixi Basin, eastern Heilongjiang Province,China.Among the angiospermous fossils there are 5 species belonging to 5 genera (including 4 gen.et sp.nov.) reported in this paper.Their microphyllous leaves with irregular venations show the characteristics of some primitive angiosperms whose age is mostly corresponding to the late Hauterivian-early Barremian, partly proved by the underlying conformably marine beds with the Valanginian-Hauterivian dinoflagellates revealed newly also by the authors.

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 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.

A Miocene Flora from Daotaiqiao Formation in Sifangtai Village,Huanan County,Heilongjiang Province,NE China with Palaeoclimatical and Palaeophytogeological Significance

A Neogene biota was found from the yellowish green or dark gray clay of the Daotaiqiao Formation in gold placer mines in Sifangtai Village,Huanan County,Heilongjiang Province,NE China in the 1990s.The age was determined biostratigraphically to be late Middle Miocene to Late Miocene(most possibly Late Miocene) by vertebrate fossils and floral (including palynological) assemblage analyses.The Miocene age(showing drastic global climate

Palaeogene Angiosperm flora and environmental implications of Intertrappean Series of Central India

The Palaeogene represents the age of spread and diversification of angiosperms in the Indian sub-continent. The palaeogene plant megafossils of this region can broadly are considered under(i) Deccan Intertrappean flora of CentralIndia,(ii) Eocene flora of Kutch and(iii) Eocene plants fossils from Meghalaya. Among the fossil flora recovered from the Deccan Intertrappean sites of central India consists of well preserved fossil representing all the major groups of the Plant Kingdom. Among the reported angiosperms Aerorhizos, Aeschynomene, Cyperaceoxylon, Bridelioxylon(affinities with marshy Bridelia hamiltoniana), Nymphaeocaulon are the indicators of a marshy environment. Nipadites, Nypa, Cocos, Palmoxylon(Cocos) sundaram, Sonneratioxylon, Sahnianthus, Enigmocarpon, Viracarpon(affinities with Pandanaceae) are the indicators of coastal or estuarine, saline environment. Anogeissusoxylon, Boswellia, Phyllites, Sahnipushpum(affinities with Araceae), Ebenoxylon(affinities with Diospyros melanoxylon), Euphorbioxylon(affinities with Euphorbiaceae), Grewioxylon(affinities with Grewia tiliaefolia), Rhamnoxylon, Sapindoxylon, Syzygioxylon are capable of surviving in a climate not unlike the one prevailing presently in this region. Ailanthoxylon, Barringtonioxylon, Elaeocarpoxylon, Grewioxylon, Indocarpa(affinities with Guttiferae), Lagerstroemia, Musa and Musocaulon, Sparganium, Viracarpon are the indicators of a more humid climate in the past. The 38 species of Palmoxylon and 19 of other palm parts(Nypa excluded) variously described as Carpolithus, Deccanthus, Palmocarpon, Palmophyllum, Palmostrobus, Rhizopalmoxylon and Tricoccites are indicative of coastal habitat. Thus the reported flora consists of taxa belonging to marine, esturine, freshwater and terrestrial habitat with both evergreens to deciduous forms. It is suggestive of an equable warm and moist tropical climate over the whole of peninsular India during the Palaeogene.

Low latitude floral assemblage from the Late Oligocene sediments of Assam and its palaeoclimatic and palaeogeographic significance

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 the whole country. The assemblage is also important to confirm whether the suturing between the Indian and Eurasian plates was complete to facilitate plant migration or not. All the reported plant fossils clearly indicate the prevalence of tropical climate in the region during the deposition of the sediments. As the majority of taxa occur in tropical evergreen to moist deciduous and littoral and swampy forest, a warm and humid climate may be envisaged in Upper Assam during the Late Oligocene. The abundance of palms and pantropical megathermal plant families in the Makum Coalfield indicate that the cold month mean temperature(CMMT) was not less than 18°C. The quantitative palaeoclimate reconstruction indicates a monsoonal climate during the period with the same intensity as that of the modern day. The absence of Southeast Eurasian elements in the fossil assemblage provides clear evidence that suturing between the Indian and Asian plates was not complete till the Late Oligocene. Several modern analogues of the fossil taxa are now endemic to the Western Ghats which lies in the same palaeolatitude.

Cenozoic flora of western India and its significance in palaeoclimatic and palaeophytogeographic interpretation

The Cenozoic flora of western India(Rajasthan and Gujarat) is adversely affected by the tectonic activity such as collision of the Indian subcontinent with the Eurasian plate which is responsible for the Himalayan and Tibetan Plateau uplift. This collision and its resultants affected the ubiquitous tropical lowland vegetation of the Indian subcontinent(including western India) and are responsible for different types of topographic regions as seen today in the Indian subcontinent. The region is important as it has witnessed a drastic change in climate of the region since the Cenozoic time and also provided opportunities to the western and eastern flora to intermingle. The main basins in western India comprising Cenozoic sequences are: Bikaner-Nagaur, Jaisalmer and Barmer in Rajasthan and Kachchh, Mainland and Saurashtra in Gujarat. These basins are very rich in lignite which is the main source of electric power generation in western India. This lignite is mainly of Eocene in age. The Cenozoic flora of western India was almost tropical growing in well drained areas as compared to arid to sub-humid regions with xeric vegetation today. The reported fossils are represented by leaves, woods, fruits and seeds. The leaves are abundant in the Palaeogene as compared to the Neogene. The Neogene period can be marked by the abundant legumes and dipterocarpaceous remains. The important families viz., Anacardiaceae, Annonaceae, Arecaceae, Calophyllaceae, Clusiaceae, Combretaceae, Euphorbiaceae, Flacourtiaceae, Icacinaceae, Lauraceae, Lythraceae, Meliaceae, Moraceae, Myrtaceae, Pandanaceae and Sonneratiaceae have been reported from the Palaeogene sediments, whereas Anacardiaceae, Araucariaceae, Arecaceae, Combretaceae, Dipterocarpaceae, Fabaceae, Lauraceae, Lecythidaceae, Lythraceae, Malvaceae, Meliaceae, Moraceae, Podocarpaceae, Rhamnaceae, Rhizophoraceae, Rutaceae, Sapindaceae and Sonneratiaceae are known from the Neogene sediments. All the recovered elements strongly indicate the presence of much better climatic conditions in the region during the Cenozoic as compared to the present. More importantly, a fossil fruit of Cocos L. described from the Eocene sediments of Rajasthan further indicates the presence of sea in the nearby area at the time of deposition of the sediments. The recovery of a few African elements from western India provides the evidence of establishment of land connections between India and Africa up to the Plio-Pleistocene through which these elements could enter the Indian subcontinent.