Articles de revues : « Coniferâs, Fossil »

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Ram-Awatar et A. Rajanikanth. « Triassic Conifer wood from the Tiki Formation, South Rewa Basin, Madhya Pradesh, India ». Journal of Palaeosciences 56 (31 décembre 2007) : 127–32. http://dx.doi.org/10.54991/jop.2007.63.

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The present paper records a conifer wood from the Triassic sequence of the Tiki Formation, ~3 km NE of Tiki Village, district Shahdol, Madhya Pradesh, India. Since Triassic wood records are hardly known from India when compared to leaf fossils, the present report of podocarpean wood provides additional evidence for the existence of conifers in the otherwise pteridosperm dominated fossil flora of South Rewa Basin during the Carnian-Norian times.

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Jordan, Gregory J., Raymond J. Carpenter, Jennifer M. Bannister, Daphne E. Lee, Dallas C. Mildenhall et Robert S. Hill. « High conifer diversity in Oligo-Miocene New Zealand ». Australian Systematic Botany 24, n^o 2 (2011) : 121. http://dx.doi.org/10.1071/sb11004.

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Eight species of Podocarpaceae foliage are recognised from the late Oligocene or early Miocene Newvale site, South Island, New Zealand, and the following five new species are described: two of Dacrydium Lamb. and one each of Dacrycarpus (Endl.) de Laub., Phyllocladus Rich. ex Mirb. and Halocarpus Quinn. The latter is the first macrofossil record of this New Zealand endemic genus. All these conifers, plus Agathis Salisb., Microcachrys Hook.f. and Podocarpus Pers., co-occurred in the local vegetation at Newvale. In conjunction with prior records of macrofossils and pollen, these fossils indicate that the late Paleogene to early Neogene conifer flora of New Zealand was very diverse, with all but one of the extant genera present, together with several regionally or globally extinct genera, and multiple species of many of these genera. This fossil diversity is similar to the Paleogene fossil conifer diversity observed in south-eastern Australia (and particularly Tasmania) and in parts of North America.

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Yao, Zhao-Qi, Lu-Jun Liu, Gar W. Rothwell et Gene Mapes. « Szecladia new genus, a late Permian conifer with multiveined leaves from South China ». Journal of Paleontology 74, n^o 3 (mai 2000) : 524–31. http://dx.doi.org/10.1017/s0022336000031784.

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A conifer from the uppermost Permian with small, helically arranged leaves is described from the Guangxi Autonomous Region and Guizhou Province of South China as Szecladia multinervia, new genus and species. The material includes both impression specimens and the first anatomically preserved Paleozoic conifer fossils from China. Shoots are irregularly branched, with small, helically arranged, multiveined leaves. Stems display an endarch eustele with abundant, dense wood. Leaf traces diverge from the stele as a single bundle that divides several times in the cortex and at the base of the leaves, forming about seven or eight parallel veins in each leaf. Szecladia is the earliest known conifer with multiveined leaves and it represents a distinctive coniferous element of the uppermost Permian Cathaysian flora in South China. Szecladia further demonstrates that conifers with wood and leaf venation suggestive of the Podocarpaceae may have evolved by the end of the Paleozoic.

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Bomfleur, Benjamin, Christian Pott et Hans Kerp. « Plant assemblages from the Shafer Peak Formation (Lower Jurassic), north Victoria Land, Transantarctic Mountains ». Antarctic Science 23, n^o 2 (23 novembre 2010) : 188–208. http://dx.doi.org/10.1017/s0954102010000866.

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AbstractThe Jurassic plant fossil record of Gondwana is generally meagre, which renders phytogeographic and palaeoclimatic interpretations difficult to date. Moreover, plant fossil assemblages mainly consist of impressions/compressions with rather limited palaeobiological and palaeoecological significance. We here present a detailed survey of new Early Jurassic plant assemblages from the Pliensbachian Shafer Peak Formation, north Victoria Land, Transantarctic Mountains. Some of the well-preserved fossils yield cuticle. The floras consist of isoetalean lycophytes, sphenophytes, several ferns, bennettitaleans, and conifers. In addition, three distinct kinds of conifer shoots and needles were obtained from bulk macerations. The composition of the plant communities is typical for Jurassic macrofloras of Gondwana, which underscores the general homogeneity of Southern Hemisphere vegetation during the mid-Mesozoic. Altogether, the plant fossil assemblages indicate humid and warm temperate conditions, which is in contrast to recent palaeoclimatic models that predict cool temperate climates for the continental interior of southern Gondwana during the Jurassic. However, there is no evidence for notable soil development or peat accumulation. The environmental conditions were apparently very unstable due to intense volcanic activity that resulted in frequent perturbation of landscape and vegetation, hampering the development of long-lived climax communities. Cuticles of bennettitaleans and conifers show xeromorphic features that may have been beneficial for growth in this volcanic environment.

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Hansen, Barbara C. S. « Conifer stomate analysis as a paleoecological tool : an example from the Hudson Bay Lowlands ». Canadian Journal of Botany 73, n^o 2 (1 février 1995) : 244–52. http://dx.doi.org/10.1139/b95-027.

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The identification of conifer stomata in fossil pollen preparations of peat cores from the Hudson Bay Lowlands is used to determine the local presence of conifers in lieu of macrofossil analyses. The differentiation of eight conifer stomate types (Picea type, Larix laricina, Pinus sp., Abies sp., Tsuga mertensiana, Tsuga heterophylla, Chamaecyparis nootkatensis, and Thuja type) is accomplished with a key, diagrammatic stomate illustrations, photographs, and measurements. Results of fossil conifer-stomate analyses indicate that both Picea and Larix arrived locally in the Albany River area of the Hudson Bay Lowlands about 4800 BP. In the Old Man Bog area, Larix arrived earlier, about 6000 BP, but Picea arrived more than 2000 years later (3700 BP). Fossil stomate and pollen results are compared. Key words: conifer stomata, local conifer presence, Hudson Bay Lowlands.

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Kunzmann, L., B. A. R. Mohr et M. E. C. Bernardes-de-Oliveira. « Gymnosperms from the Lower Cretaceous Crato Formation (Brazil). I. Araucariaceae and Lindleycladus (incertae sedis) ». Fossil Record 7, n^o 1 (1 janvier 2004) : 155–74. http://dx.doi.org/10.5194/fr-7-155-2004.

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Fossil conifers from the Early Cretaceous, most likely late Aptian, Crato Formation were studied. The excellent preservation of several of those fossils allowed detailed investigations of the leaf epidermis by light microscope (LM) and by scanning electron microscope (SEM). Members of two conifer taxa were recognized: The Araucariaceae are represented by a female cone of cf. Araucaria spec. A juvenile cone (Araucariostrobus spec.) and sterile foliage shoots of Brachyphyllum obesum might be attributed to the Araucariaceae as well. The morpho-genus Lindleycladus (incertae sedis) is represented by foliage shoots. The occurrence of Lindleycladus is the first record of this extinct morpho-genus in the Southern Hemisphere. Anatomical features of these conifers are interpreted as adaptations to a warm seasonally dry climate. Taphonomic problems concerning these conifer remains are discussed. Fossile Koniferen aus der unterkretazischen, höchstwahrscheinlich oberaptischen Crato Formation wurden untersucht. Die ausgezeichnete Erhaltung einiger Exemplare gestattete die Analyse von Blattepidermen mittels Licht- und Rasterelektronen-mikroskop. Vertreter zweier Koniferentaxa wurden nachgewiesen: Araucariaceae kommen mit einem weiblichen Zapfen von cf. Araucaria spec. vor. Ein juveniler Zapfen (Araucariostrobus spec.) und sterile Zweige mit der Beblätterung der Morpho-Species Brachyphyllum obesum werden unter Vorbehalt ebenfalls zu den Araucariaceae gestellt. Vegetative Organe der Morpho-Gattung Lindleycladus (incertae sedis) sind ebenfalls erhalten. Das Vorkommen von Lindleycladus ist ein erster Nachweis dieser fossilen Morpho-Gattung in der Südhemisphäre. Anatomische Merkmale dieser Koniferen werden als Anpassungen an ein warmes, saisonal trockenes Klima gedeutet. Im Zusammenhang mit den Koniferenresten werden taphonomische Probleme diskutiert. doi:<a href="http://dx.doi.org/10.1002/mmng.20040070109" target="_blank">10.1002/mmng.20040070109</a>

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Atkinson, Brian A., Dori L. Contreras, Ruth A. Stockey et Gar W. Rothwell. « Ancient diversity and turnover of cunninghamioid conifers (Cupressaceae) : two new genera from the Upper Cretaceous of Hokkaido, Japan ». Botany 99, n^o 8 (août 2021) : 457–73. http://dx.doi.org/10.1139/cjb-2021-0005.

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Conifers of the taxodiaceous grade of Cupressaceae were more diverse and widespread during the Mesozoic than they are today. The earliest diverging subfamily, Cunninghamioideae, only includes a single extant genus, but has at least 10 fossil genera. Here, two additional cunninghamioid genera are characterized on the basis of permineralized seed cones from the Upper Cretaceous of Hokkaido, Japan. These conifers display seed cone characters typical of cunninghamioids; however, they have a mosaic of characters that are not seen in any reported conifer of Cupressaceae. They are, therefore, designated as two new extinct species: Ohanastrobus hokkaidoensis gen. et sp. nov. and Nishidastrobus japonicum gen. et sp. nov. These newly reported conifers expand the taxonomic and morphological diversity of cunninghamioids. The stratigraphic and paleobiogeographic records of cunninghamioids and other fossil Cupressaceae with foliate seed cones indicate they peak in diversity during the Cretaceous. The living genera Taiwania and Cunninghamia appear during the Albian and Campanian, respectively, and maintain a nearly continuous fossil record through to today, while nearly all other extinct genera of Cupressaceae with foliate cones disappear by the close of the Campanian. As more ancient cunninghamioids are recovered, our understanding of macroevolutionary patterns of this once diverse lineage will be further elucidated.

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Kvaček, Jiří, et Jakub Sakala. « Late Cretaceous flora of James Ross Island (Antarctica) – preliminary report ». Czech Polar Reports 1, n^o 2 (1 juin 2011) : 96–103. http://dx.doi.org/10.5817/cpr2011-2-9.

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Fossil plants from Late Cretaceous strata (Hidden Lake Formation and Santa Marta Formation) of James Ross Basin exposed in the northern part of the James Ross Island are preliminary described. Both formations contain plant mega fossils, petrified wood, and charcoalified mesofossils. Fossil plants from the Hidden Lake Formation are represented by leaf impressions of pteridophytes (Microphyllopteris, Delosorus, Lygodium), conifers (Elatocladus, Brachyphyllum, Pagiophyllum, Araucaria, Podozamites vel Lindleycladus), Bennettitales vel Cycadales (Zamites vel Dioonites sp.) and angiosperms (Cinnamomoides, Dicotylophyllum ssp., Proteophyllum, Juglandi-phyllum vel Dicotylophyllum). Fossil wood can be attributed to the very broadly defined morphogenus Antarctoxylon Poole & Cantrill.

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Condamine, Fabien L., Daniele Silvestro, Eva B. Koppelhus et Alexandre Antonelli. « The rise of angiosperms pushed conifers to decline during global cooling ». Proceedings of the National Academy of Sciences 117, n^o 46 (2 novembre 2020) : 28867–75. http://dx.doi.org/10.1073/pnas.2005571117.

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Competition among species and entire clades can impact species diversification and extinction, which can shape macroevolutionary patterns. The fossil record shows successive biotic turnovers such that a dominant group is replaced by another. One striking example involves the decline of gymnosperms and the rapid diversification and ecological dominance of angiosperms in the Cretaceous. It is generally believed that angiosperms outcompeted gymnosperms, but the macroevolutionary processes and alternative drivers explaining this pattern remain elusive. Using extant time trees and vetted fossil occurrences for conifers, we tested the hypotheses that clade competition or climate change led to the decline of conifers at the expense of angiosperms. Here, we find that both fossil and molecular data show high congruence in revealing 1) low diversification rates, punctuated by speciation pulses, during warming events throughout the Phanerozoic and 2) that conifer extinction increased significantly in the Mid-Cretaceous (100 to 110 Ma) and remained high ever since. Their extinction rates are best explained by the rise of angiosperms, rejecting alternative models based on either climate change or time alone. Our results support the hypothesis of an active clade replacement, implying that direct competition with angiosperms increased the extinction of conifers by pushing their remaining species diversity and dominance out of the warm tropics. This study illustrates how entire branches on the Tree of Life may actively compete for ecological dominance under changing climates.

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Taylor, David W., J. Michael Moldowan et Leo J. Hickey. « Investigation of the terrestrial occurrence and biological source of the petroleum geochemical biomarker oleanane ». Paleontological Society Special Publications 6 (1992) : 286. http://dx.doi.org/10.1017/s2475262200008467.

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Oleanane is a triterpane that is commonly found in Late Cretaceous (Campanian) through Cenozoic marine and deltaic rocks and related oils. Based on its affinity to the β-Amyrin group of natural products and its abundance in Tertiary deltaic sediments and oils, such as in the Niger Delta, oleanane is thought to be a geochemical fossil of terrestrial flowering plants. The β-Amyrin group forms the basis of many angiosperm triterpenoids and triterpenoid saponins. These compounds appear in moderately advanced flowering plant lineages and are often used as a defense against herbivores. This group of compounds has not been reported from any other seed plant group, including conifers.We examined a suite of middle to early Cretaceous terrestrial sediments and plant fossils for the presence of oleanane. The existence of oleanane was documented by Gas Chromatography - Mass Spectrometry (GC-MS) and confirmed with Metastable Reaction Monitoring (MRM) GC-MS.Oleanane was identified from fossil bennettitaleans, an extinct group of seed plants. Cycadeoidea paynei and C. superba are permineralized fossil stems and are from the Early Cretaceous Inyan Kara Group of the Black Hills, SD. Oleanane was also found in carbonaceous compressed leaf fossils of Dioonites from the Barremian - early Aptian (Zone I) of the Potomac Group from Richmond, VA. This increases the number of seed plant groups known to have oleanane, and is of additional interest as the bennettitaleans are thought to be closely related to angiosperms.Oleanane was not found in contemporaneous fossil conifers. Our sample consisted of fossil conifer wood collected from the Campanian Magothy Beds of Martha's Vineyard, MA; the Cenomanian Raritan Formation of Sayreville, NJ; and the Barremian - early Aptian Patuxent Formation of Greenbelt, MD.Confirmed reports of oleanane have been from Late Cretaceous and younger marine sediments. We now report oleanane from Early Cretaceous terrestrial strata of the Inyan Kara Group. In addition we systematically sampled the sequence of Cretaceous terrestrial sediments of the coastal plain of the eastern U.S.A, and found oleanane in the Barremian - early Aptian (Zone I) Potomac Group. Preliminary data indicate variation in the occurrence of oleanane in contemporaneous Early Cretaceous sites from the Potomac Group. The localities accumulated in different depositional environments and the occurrence may be controlled by lithofacies.

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Alexander, R., R. A. Noble et R. I. Kagi. « FOSSIL RESIN BIOMARKERS AND THEIR APPLICATION IN OIL TO SOURCE-ROCK CORRELATION, GIPPSLAND BASIN, AUSTRALIA ». APPEA Journal 27, n^o 1 (1987) : 63. http://dx.doi.org/10.1071/aj86007.

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Diterpanes occur widely in the resins of modern conifers, suggesting that sedimentary diterpanes are chemical markers for fossil resins, particularly those derived from conifers. In this paper, the use of the relative abundance of these chemical fossils for establishing genetic relationships between the organic matter in sediments and crude oils has been demonstrated using sediments and crude oils from the Gippsland Basin.The crude oils were characterised by their remarkably uniform distributions of diterpanes and similar relative amounts of diterpanes and hopanes. In contrast, the sediments showed much greater variability, with only one sediment horizon, an organic-rich shale, showing the same properties as the crude oils.

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Wilf, Peter. « Eocene “Chusquea” fossil from Patagonia is a conifer, not a bamboo ». PhytoKeys 139 (3 février 2020) : 77–89. http://dx.doi.org/10.3897/phytokeys.139.48717.

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Chusquea oxyphylla Freng. & Parodi, 1941, a fossilized leafy branch from the early Eocene (52 Ma), late-Gondwanan Laguna del Hunco biota of southern Argentina, is still cited as the oldest potential bamboo fossil and as evidence for a Gondwanan origin of bamboos. On recent examination, the holotype specimen was found to lack any typical bamboo characters such as nodes, sheaths, ligules, pseudopetioles, or parallel leaf venation. Instead, it has decurrent, clasping, univeined, heterofacially twisted leaves with thickened, central-longitudinal bands of presumed transfusion tissue. These and other features allow confident placement in the living Neotropical and West Pacific disjunct genus Retrophyllum (Podocarpaceae), which was recently described from the same fossil site based on abundant, well-preserved material. However, the 1941 fossil holds nomenclatural priority, requiring the new combination Retrophyllum oxyphyllum (Freng. & Parodi) Wilf, comb. nov. No reliable bamboo fossils remain from Gondwana, and the oldest South American bamboo fossils are Pliocene. Chusquea joins a growing list of living New World genera that are no longer included in Paleogene Patagonian floras, whose extant relatives are primarily concentrated in Australasia and Malesia via the ancient Gondwanan route through Antarctica.

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Mendes, Mário Miguel, et Else Marie Friis. « The Nossa Senhora da Luz flora from the Early Cretaceous (early Aptian-late Albian) of Juncal in the western Portuguese Basin ». Acta Palaeobotanica 58, n^o 2 (1 décembre 2018) : 159–74. http://dx.doi.org/10.2478/acpa-2018-0015.

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AbstractA new fossil flora is described from the Early Cretaceous of the western Portuguese Basin, based on a combined palynological-mesofossil study. The fossil specimens were extracted from samples collected in the Nossa Senhora da Luz opencast clay pit complex near the village of Juncal in the Estremadura region. The plant-bearing sediments belong to the Famalicão Member of the Figueira da Foz Formation, considered late Aptianearly Albian in age. The palynological assemblage is diverse, including 588 spores and pollen grains assigned to 30 genera and 48 species. The palynoflora is dominated by fern spores and conifer pollen. Angiosperm pollen is also present, but subordinate. The mesofossil flora is less diverse, including 175 specimens ascribed to 17 species, and is dominated by angiosperm fruits and seeds. The mesofossil flora also contains conifer seeds and twigs as well as fossils with selaginellaceous affinity. The fossil assemblage indicates a warm and seasonally dry climate for the Nossa Senhora da Luz flora.

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Miller, Dane M., Ian M. Miller et Stephen T. Jackson. « Biogeography of Pleistocene conifer species from the Ziegler Reservoir fossil site, Snowmass Village, Colorado ». Quaternary Research 82, n^o 3 (novembre 2014) : 567–74. http://dx.doi.org/10.1016/j.yqres.2014.06.003.

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AbstractPleistocene biogeography of conifer species is poorly known in much of western North America. We conducted morphological studies on 201 conifer cones and cone fragments recovered from Pleistocene sediments at the Ziegler Reservoir fossil site (2705 m) near Snowmass Village, Colorado. The basin, formed ~155–130 ka, contains fossil-bearing lacustrine, palustrine, and colluvial sediments spanning approximately 85 ka. Using a suite of morphological characters, particularly cone-scale bracts, we differentiated species of Abies, Picea, and Pseudotsuga. All fossil Abies specimens were assignable based on bract morphology to Abies concolor, which is currently absent from central Colorado (nearest populations are 160 km southwest of the site). A. concolor occurs only in sediments of MIS 5d and 5c. Pseudotsuga menziesii and Picea engelmannii cones occurred in sediments corresponding to MIS 5e, 5d, 5c, and 5a. A fourth conifer species, occurring in sediments of MIS 5e, 5d, 5c, and 5a, is difficult to assign to any extant species. Bract morphology is similar to Picea pungens, which grows near the site today, but scale morphology is unlike P. pungens. These fossils may represent ancestral P. pungens, an extinct variant, or an extinct sister species.

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Gee, Carole, Douglas Sprinkel, Mary Beth Bennis et Dale Gray. « Silicified logs of Agathoxylon hoodii (Tidwell et Medlyn) comb. nov. from Rainbow Draw, near Dinosaur National Monument, Uintah County, Utah, USA, and their implications for araucariaceous conifer forests in the Upper Jurassic Morrison Formation ». Geology of the Intermountain West 6 (20 novembre 2019) : 77–92. http://dx.doi.org/10.31711/giw.v6.pp77-92.

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A new local flora of silicified logs and wood has been discovered in the Upper Jurassic Morrison Formation in the Rainbow Draw area near Dinosaur National Monument, northeastern Utah, USA. Fossil logs and wood were found in the Salt Wash Member at nine sites at Rainbow Draw and at one site near Miners Draw, south of Blue Mountain. The fossil logs are large and relatively intact, the longest measuring 11 m. The wood is well preserved, coniferous, and can be identified to the species level. Diagnostic anatomical features include resin plugs in the ray cells and axial tracheids, araucarioid tracheary pitting and crossfield pitting, and the lack of resin canals and true, regularly occurring growth rings. This taxon of fossil wood, originally described as Araucarioxylon hoodii Tidwell et Medlyn, is recognized here as a new combination, Agathoxylon hoodii (Tidwell et Medlyn) Gee, Sprinkel, Bennis et Gray, which pertains to the conifer family Araucariaceae. Based on the preserved girth of the logs, the minimum height of the trees could be reconstructed. The largest fossil logs measured at least 127 cm in diameter and hence reached a minimum height of 28 m. Judging from the growth habit of all naturally occurring araucariaceous trees today, the fossil plants likely formed forests of moderately tall trees and were well over 100 years old. The lack of true growth rings shows that there was no seasonality in the local paleoclimate, neither variations in summer–winter temperatures, nor wet–dry cycles. Thus, during the Late Jurassic, tall conifer forests with Agathoxylon hoodii grew in at least two areas in what is now Utah: east of the city of Vernal and near Mt. Ellen in the Henry Mountains. Coupled with the fossil evidence of conifer seed cones and pollen found in the Morrison Formation throughout eastern Utah, the newly discovered fossil logs and wood argue for the reconstruction of Upper Jurassic habitats in this region as mesic and wooded, and the climate as equable, not seasonal, nor semi-arid or arid.

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Matthews Jr., John V., Robert J. Mott et Jean-Serge Vincent. « Preglacial and Interglacial Environments of Banks Island : Pollen and Macrofossils from Duck Hawk Bluffs and Related Sites ». Géographie physique et Quaternaire 40, n^o 3 (4 décembre 2007) : 279–98. http://dx.doi.org/10.7202/032649ar.

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ABSTRACT Sediments ranging in age from Tertiary to Late Quaternary are exposed at Duck Hawk Bluffs near Sachs Harbour on Banks Island (NWT). Fossil pollen and macrofossils of plants and arthropods from various nonglacial sediments at Duck Hawk Bluffs and related sites on Banks and Victoria islands make it possible to infer some of the climatic/biotic changes during that time span. At the time of deposition of the Miocene-Pliocene Beaufort Formation, southern Banks Island supported a rich coniferous forest, containing several species of conifers and various hardwoods. An upper member of the Beaufort Fm. is characterized by a more depauperate coniferous forest assemblage, yet still contains plants now foreign to the entire NWT. The late Tertiary/early Quaternary Worth Point Formation was deposited when larch-dominated forest-tundra characterized southern Banks Island. Larch may have grown on the island during the following Morgan Bluffs Interglaciation (>730 ka), but in other respects the flora and fauna of that time seem to have been low Arctic in character. Similar conditions existed during the Cape Collinson Interglaciation ( = Sangamon), though by that time, coniferous trees had definitely disappeared from the island.

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Kerp, Hans, Patrick Blomenkemper, Abdalla Abu Hamad et Benjamin Bomfleur. « The fossil flora of the Dead Sea region, Jordan – A late Permian Garden of Delights ». Journal of Palaeosciences 70, n^o (1-2) (10 septembre 2021) : 135–58. http://dx.doi.org/10.54991/jop.2021.12.

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The Umm Irna Formation, Jordan, holds one of the most peculiar late Permian plant–fossil assemblages worldwide. Over the last decades of field work, several localities close to the eastern shore of the Dead Sea have yielded a highly diverse ‘mixed flora’ of mesic to xeric environments encompassing elements that are typical either for different floral realms or for different time periods of Earth History. Taxa typical for particular floral realms include, e.g. Cathaysian gigantopterids and Lobatannularia, Euramerican conifers such as Otovicia hypnoides, or the characteristic Gondwanan seed ferns Glossopteris and Dicroidium. Moreover, most taxa are typical for the Permian, some assemblages have also yielded precocious occurrences of taxa that have so far been considered typical for the Mesozoic, such as Umkomasiaceae, Bennettitales, and podocarp conifers. In most cases, fossils from the Umm Irna Formation show well–preserved cuticles that allow sound systematic placement and contribute to the reconstruction of dispersed plant parts into whole–plant–taxa. Altogether, the Umm Irna Formation provides an exceptional window into depositional environments and vegetation types that are rarely preserved in the fossil record but that are crucial for our understanding of plant evolution.

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Moreau, Jean-David, Romain Vullo, Sylvain Charbonnier, Romain Jattiot, Vincent Trincal, Didier Néraudeau, Emmanuel Fara et al. « Konservat-Lagerstätten from the Upper Jurassic lithographic limestone of the Causse Méjean (Lozère, southern France) : palaeontological and palaeoenvironmental synthesis ». Geological Magazine 159, n^o 5 (17 janvier 2022) : 761–81. http://dx.doi.org/10.1017/s0016756821001382.

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AbstractSince the 1980s, the Upper Jurassic lithographic limestone of the Causse Méjean (southern France) has been known by local naturalists to yield fossils. However, until the beginning of the 21st century, this plattenkalk remained largely undersampled and scientifically underestimated. Here, we present the results of two decades of prospection and sampling in the Drigas and the Nivoliers quarries. We provide the first palaeontological inventory of the fossil flora, the fauna and the ichnofauna for these localities. The fossil assemblages show the co-occurrence of marine and terrestrial organisms. Marine organisms include algae, bivalves, brachiopods, cephalopods (ammonites, belemnites and coleoids such as Trachyteuthis), echinoderms, decapod crustaceans (ghost shrimps, penaeoid shrimps and glypheoid lobsters) and fishes (including several actinopterygians and a coelacanth). Terrestrial organisms consist of plant remains (conifers, bennettitaleans, pteridosperms) and a single rhynchocephalian (Kallimodon cerinensis). Ichnofossils comprise traces of marine invertebrates (e.g. limulid trackways, ammonite touch mark) as well as coprolites and regurgitalites. Given the exquisite preservation of these fossils, the two quarries can be considered as Konservat-Lagerstätten. Both lithological features and fossil content suggest a calm, protected and shallow-marine environment such as a lagoon partially or occasionally open to the sea. Most fossils are allochthonous to parautochthonous and document diverse ecological habitats. Similarly to other famous Upper Jurassic plattenkalks of western Europe such as Solnhofen, Cerin or Canjuers, the Causse Méjean is a key landmark for our understanding of coastal/lagoonal palaeoecosystems during the Kimmeridgian–Tithonian interval.

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Staccioli, Giuseppe, Alberto Sturaro, Giorgio Parvoli, Gloria Menchi et Ugo Matteoli. « The Lipophilic Extractives of an Interglacial Fossil Picea abies from Zeifen (Germany) ». Holzforschung 53, n^o 4 (1 juillet 1999) : 391–96. http://dx.doi.org/10.1515/hf.1999.065.

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Summary A fossil Picea abies from Zeifen (Germany), 100,000 years old and still presenting good physical and anatomical properties, is analysed with respect to its lipophilic content. Comparisons are made with a recent Picea abies, with a subfossil larch and with Taxodioxylon gypsaceum fossils ranging from 1.7 to 20 million years ago. Due to the relatively small age and the low degree of degradation, terpenes having structures intermediate between the original compounds and the final terpanes are looked for. Lipophilic components obtained from the fossil Picea abies by extraction with dichloromethane include linear alkanes, fatty acids, high MWs alcohols and terpenoids such as sesquiterpanes, diterpanes and diterpenoids. Some of extractive components result unchanged after the process of ageing while others correspond to substances derived by a process of hydrolysis of original extractives occurring in recent Picea abies. Diterpanes (norabietatriene, norpimarane, retene and α-phyllocladane) correspond to those present in most fossils of conifers, even if a trend to the formation of demethylated compounds is observed. Diterpenoids, on the contrary, are present exclusively as the dehydroabietic acid structure, the form preceding or responsible of those of most diterpanes, while different structures are not found. Since intermediate compounds with structures different from the abietic one are absent they might be looked for in younger fossils. The presence of a large amount of terpanes places this fossil rather closer to Taxodioxylon gypsaceum samples than to the subfossil larch.

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Brown, Peter M., Stephen E. Nash et Douglas Kline. « Identification and dendrochronology of wood found at the Ziegler Reservoir fossil site, Colorado, USA ». Quaternary Research 82, n^o 3 (novembre 2014) : 575–79. http://dx.doi.org/10.1016/j.yqres.2014.02.006.

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AbstractOver 300 wood fossils were collected from the Ziegler Reservoir fossil site near Snowmass Village in central Colorado, USA. Wood fossils range from fragments of stems and branches only a few centimeters in diameter and length to whole logs >50 cm diameter and >10 m length. Many of the fossils were collected from a “beach” horizon, where they appear to have been washed up on the side of the interglacial lake and buried. The wood is mainly fir (Abies sp.) or Douglas-fir (Pseudotsuga menziesii), with some spruce (Picea sp.), pine (Pinus sp.), and at least one other unidentified conifer species. Douglas-fir and species of fir, spruce, and pine are common in the area today. Dendrochronological analyses compared annual growth rings in fossil wood to similar data from modern trees. Results suggest that fossil trees from the beach horizon grew under similar environmental conditions and annual climate variability as today. Three Douglas-firs and several fir logs also appear to have been alive at the same time based on crossdating of ring widths and other ring characteristics. These trees may have died at the same time, suggesting a stand mortality event in the surrounding forest that resulted in numerous logs being buried synchronously in the beach horizon.

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Herman, A. B., V. V. Kostyleva, P. A. Nikolskii, A. E. Basilyan et A. E. Kotel’nikov. « New data on the late cretaceous flora of the New Siberia island, New Siberian Islands ». Стратиграфия 27, n^o 3 (22 avril 2019) : 53–69. http://dx.doi.org/10.31857/s0869-592x27353-69.

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New plant fossils collected in 2016 from the Derevyannye Gory Formation on the New Siberia Island are studied. Thirty species of fossil plants are identified and illustrated. They belong to liverworts, ferns, ginkgoaleans, conifers and angiosperms. Sixteen of them have not beed found in the New Siberia Flora before. A new angiosperm species Dalembia (?) gracilis Herman is described. The New Siberia Flora is characterised by a moderately high taxonomic diversity, predominance of conifers and angiosperms with large-leafed platanoids and trochodendroids being the most abundant among angiosperms, by predominance of dentate-margined angiosperms and rarity of plants with entire-margined leaves, and by absence of cycadaleans and bennettitaleans. The flora existed during the Turonian–Coniacian time interval and most probably should be dated as Turonian. Plants of the New Siberia Flora experienced a warm-temperate humid climate with warm summers, mild frost-free winters and insignificant seasonality in precipitation.

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Leslie, Andrew B. « Predation and protection in the macroevolutionary history of conifer cones ». Proceedings of the Royal Society B : Biological Sciences 278, n^o 1720 (23 février 2011) : 3003–8. http://dx.doi.org/10.1098/rspb.2010.2648.

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Conifers are an excellent group in which to explore how changing ecological interactions may have influenced the allocation of reproductive tissues in seed plants over long time scales, because of their extensive fossil record and their important role in terrestrial ecosystems since the Palaeozoic. Measurements of individual conifer pollen-producing and seed-producing cones from the Pennsylvanian to the Recent show that the relative amount of tissue invested in pollen cones has remained constant through time, while seed cones show a sharp increase in proportional tissue investment in the Jurassic that has continued to intensify to the present day. Since seed size in conifers has remained similar through time, this increase reflects greater investment in protective cone tissues such as robust, tightly packed scales. This shift in morphology and tissue allocation is broadly concurrent with the appearance of new vertebrate groups capable of browsing in tree canopies, as well as a diversification of insect-feeding strategies, suggesting that an important change in plant–animal interactions occurred over the Mesozoic that favoured an increase in seed cone protective tissues.

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Prakash, Neeru, Neelam Das, Nishith Y. Bhat et Paras M. Solanki. « Reappraisal of palaeofloristics of Himmatnagar Sandstone vis-à-vis palaeogeographic significance ». Journal of Palaeosciences 65, n^o (1-2) (31 décembre 2016) : 169–76. http://dx.doi.org/10.54991/jop.2016.308.

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The state of Gujarat physiographically comprises three distinct zones–the Gujarat Mainland, the Saurashtra and the Kachchh. The sedimentary deposits of Himmatnagar Sandstone (23°36'00": 72°57'45") are mainly exposed in Gujarat Mainland. Palaeobotanical study reveals occurrence of plant fossils Matonidium, Weichselia, Cladophlebis, Gleichenia, Sphenopteris, Dictyophyllum, Pachypteris, Pagiophyllum and Araucarites. Bennettitales are absent. Numerically pteridophytes are represented by 61%, pteridosperms are represented by 7% and cyacads are represented by 7% while conifers are represented by 24%. The assemblage is compared and correlated with contemporaneous deposits in India and other Gondwanic continents and found that it is coeval to fossil floral assemblage of Dharangdhara Formation, (Saurashtra) and Bansa Formation of South Rewa (in central part of India) and Athgarh Formation on east–coast of India, in having common occurrence of Wealden frond Weichselia with dominance of pteridophytic fronds and conifers of family Araucariaceae. Due to common occurrence of pteridophytes and conifers (at generic level) the flora also resembles to Bluff flora of Alexander Island (Antarctica) and Barcó flora of Baqueró Formation of Patagonia (South America) indicating that the dispersal of biota might have taken place through Kerguelen Plateau or Gunners ridge via Antarctica.

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Wilson, Jonathan P., et Andrew H. Knoll. « A physiologically explicit morphospace for tracheid-based water transport in modern and extinct seed plants ». Paleobiology 36, n^o 2 (2010) : 335–55. http://dx.doi.org/10.1666/08071.1.

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We present a morphometric analysis of water transport cells within a physiologically explicit three-dimensional space. Previous work has shown that cell length, diameter, and pit resistance govern the hydraulic resistance of individual conducting cells; thus, we use these three parameters as axes for our morphospace. We compare living and extinct plants within this space to investigate how patterns of plant conductivity have changed over evolutionary time. Extinct coniferophytes fall within the range of living conifers, despite differences in tracheid-level anatomy. Living cycads, Ginkgo biloba, the Miocene fossil Ginkgo beckii, and extinct cycadeoids overlap with both conifers and vesselless angiosperms. Three Paleozoic seed plants, however, occur in a portion of the morphospace that no living seed plant occupies. Lyginopteris, Callistophyton, and, especially, Medullosa evolved tracheids with high conductivities similar to those of some vessel-bearing angiosperms. Such fossils indicate that extinct seed plants evolved a structural and functional diversity of xylem architectures broader, in some ways, than the range observable in living seed plants.

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Lacourse, Terri, J. Michelle Delepine, Elizabeth H. Hoffman et Rolf W. Mathewes. « A 14,000 year vegetation history of a hypermaritime island on the outer Pacific coast of Canada based on fossil pollen, spores and conifer stomata ». Quaternary Research 78, n^o 3 (23 septembre 2012) : 572–82. http://dx.doi.org/10.1016/j.yqres.2012.08.008.

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AbstractPollen and conifer stomata analyses of lake sediments from Hippa Island on the north coast of British Columbia were used to reconstruct the vegetation history of this small hypermaritime island. Between 14,000 and 13,230 cal yr BP, the island supported diverse herb–shrub communities dominated by Cyperaceae, Artemisia and Salix. Pinus contorta and Picea sitchensis stomata indicate that these conifers were present among the herb–shrub communities, likely as scattered individuals. Transition to open P. contorta woodland by 13,000 cal yr BP was followed by increases in Alnus viridis, Alnus rubra and P. sitchensis. After 12,000 cal yr BP, Pinus-dominated communities were replaced by dense P. sitchensis and Tsuga heterophylla forest with Lysichiton americanus and fern understory. Thuja plicata stomata indicate that this species was present by 8700 cal yr BP, but the pollen record suggests that its populations did not expand to dominate regional rainforests, along with Tsuga and Picea, until after 6600 cal yr BP. Conifer stomata indicate that species may be locally present for hundreds to thousands of years before pollen exceed thresholds routinely used to infer local species arrival. When combined, pollen and conifer stomata can provide a more accurate record of paleovegetation than either when used alone.

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Greenwood, David R., S. Bruce Archibald, Rolf W. Mathewes et Patrick T. Moss. « Fossil biotas from the Okanagan Highlands, southern British Columbia and northeastern Washington State : climates and ecosystems across an Eocene landscape ». Canadian Journal of Earth Sciences 42, n^o 2 (1 février 2005) : 167–85. http://dx.doi.org/10.1139/e04-100.

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The late Early to early Middle Eocene Okanagan Highlands fossil sites, spanning ~1000 km northsouth (northeastern Washington State, southern British Columbia) provide an opportunity to reconstruct biotic communities across a broad upland landscape during the warmest part of the Cenozoic. Plant taxa from these fossil sites are characteristic of the modern eastern North American deciduous forest zone, principally the mixed mesophytic forest, but also include extinct taxa, taxa known only from eastern Asian mesothermal forests, and a small number of taxa restricted to the present-day North American west coast coniferous biome. In this preliminary report, paleoclimates and forest types are reconstructed using collections from Republic in Washington State, USA., and Princeton, Quilchena, Falkland, McAbee, Hat Creek, Horsefly, and Driftwood Canyon in British Columbia, Canada. Both leaf margin analysis (LMA) and quantitative bioclimatic analysis of identified nearest living relatives of megaflora indicated upper microthermal to lower mesothermal moist environments (MAT ~1015 °C, CMMT > 0 °C, MAP > 100 cm/year). Some taxa common to most sites suggest cool conditions (e.g., Abies, other Pinaceae; Alnus, other Betulaceae). However, all floras contain a substantive broadleaf deciduous element (e.g., Fagaceae, Juglandaceae) and conifers (e.g., Metasequoia) with the bioclimatic analysis yielding slightly higher MAT than LMA. Thermophilic (principally mesothermal) taxa include various insects, the aquatic fern Azolla, palms, the banana relative Ensete, taxodiaceous conifers, Eucommia and Gordonia, taxa which may have occurred near their climatic limits. The mixture of thermophilic and temperate insect and plant taxa indicates low-temperature seasonality (i.e., highly equable climate).

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Boyarina, Nataliya, et Ganna Kovalenko. « GEOBOTANICAL ANALYSIS OF PLANT FOSSIL ASSEMBLAGES FROM THE UPPER PENNSYLVANIAN LIMNIC DEPOSITS OF THE NORTHERN CAUCASUS ». Collection of Scientific Works of the Institute of Geological Sciences of the NAS of Ukraine 16, n^o 1 (6 juin 2023) : 81–97. http://dx.doi.org/10.30836/igs.2522-9753.2023.296583.

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Analysis of plant fossil assemblages from the Upper Pennsylvanian deposits of the Northern Caucasus was carried out within the intervals, which are compared with the megafloral zones of the Stephanian of the Western European scale. The identification of the taxonomic composition and the interpretation of environments of the Late Pennsylvanian plant communities showed that the Northern Caucasus vegetation was represented by wetland and seasonally dry forests of river valleys. The wetland forests were composed of the calamitalean-fern and calamitalean-fern-pteridosperm communities of the shores of floodplain lakes and the lycopsid-calamitalean-fern-pteridosperm communities of floodplains. Throughout the Late Pennsylvanian (Stephanian and early Autunian), the most widespread taxa of wetland forests were lycophytes Subsigillaria brardii, calamitaleans with the stems of Calamites suckowii and the foliage of Annularia sphenophylloides, A. spinulosa, ferns Acitheca polymorpha, Cyathocarpus arboreus, C. cyatheus, ‘Pecopteris’ bredovii, Nemejcopteris feminaeformis, Diplazites unitus and pteridosperms Odontopteris brardii, Callipteridium gigas, C. pteridium, Pseudomariopteris cordato-ovata, Dicksonites sterzelii. The seasonally dry vegetation was widespread in the middle Stephanian (Stephanian B) and the late Stephanian–early Autunian (Stephanian C–early Autunian) and composed of the pteridosperm-conifer communities of river valley slopes. In the middle Stephanian, the drought-tolerant plants were represented by pteridosperms Odontopteris subcrenulata, Sphenopteridium cf. germanicum, Taeniopteris jejunata, cordaitaleans Cordaites sp. and conifers Walchia piniformis, Culmitzschia frondosa. In the late Stephanian–early Autunian, the seasonally dry vegetation of the river valley slopes included pteridosperms Autunia conferta, Dichophyllum flabelliferum, Sphenopteridium germanicum, Taeniopteris jejunata, conifers Walchia piniformis, Otovicia hypnoides and cordaitaleans Cordaites sp.

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Gengwu, Liu, Li Haomin et Leng Qin. « Occurrence of Late Miocene flora from north-east China ». Journal of Palaeosciences 45 (31 décembre 1996) : 440–46. http://dx.doi.org/10.54991/jop.1996.1265.

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A flora containing both plant microfossils and megafossils has been reported from four placer gold wells in Huanan County, Heilongjiang Province of north-east China. Most of the pollen and megafossil plants are in common. Families Fagaceae, Betulaceae and Pinaceae are abundant in this fossil flora which probably implies a mixed conifer and deciduous broad-leaved forest of warm temperate climate. On the basis of associated vertebrate fossils and correlation with equivalent floras a Late Miocene age has been assigned.

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Rothwell, Gar W., et Tamiko Ohana. « Stockeystrobusgen. nov. (Cupressaceae), and the evolutionary diversification of sequoioid conifer seed cones ». Botany 94, n^o 9 (septembre 2016) : 847–61. http://dx.doi.org/10.1139/cjb-2016-0025.

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An anatomically preserved seed cone from Late Cretaceous (Santonian–Coniacian) sediments of the Yezo Group on the Japanese Island of Hokkaido documents additional diversity among sequoioid conifers, and reveals previously unknown mechanisms for pollination and post-pollination seed enclosure in the conifer family Cupressaceae. The cylindrical seed cone of Stockeystrobus interdigitata gen. et sp. nov., consists of a central axis bearing helically arranged bract–scale complexes. Individual complexes are tightly packed and peltate in form, with completely fused bracts and scales. Peltate heads of adjacent complexes are attached to each other by elongated interdigitating epidermal trichomes. Each complex bears 6–8 inverted seeds on the adaxial surface of the inside of the peltate bract–scale complex head. Seeds occur in a single row, are roughly disk shaped, with broad wings in the major plane of symmetry. The nucellus is attached to the seed integument at the chalaza and free distally, with a convoluted apex. This cone reveals greater diversity of sequoioid reproductive biology than is represented among living species, and demonstrates that completely enclosed cones with well protected seeds were produced by Late Cretaceous fossil conifers of the Cupressaceae.

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Pandya, Neeru, et Sukh-Dev. « Fossil flora of Gollapalle Formation ». Journal of Palaeosciences 38 (31 décembre 1989) : 147–54. http://dx.doi.org/10.54991/jop.1989.1648.

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The plant megafossil assemblage of Gollapalle Formation, Andhra Pradesh is enriched and updated. The flora is chiefly constituted of Cladophlebis, Sphenopteris, Marattiopsis, Pachypteris, Taeniopteris, Ptillophyllum, Dictyozamites, Pterophyllum, Williamsonia, Bucklandia, Elatocladus, Pagiophyllum, Brachyphyllum and Araucarites. Conifers and cycadophytes are dominant: pteridophytes and pteridosperms are poorly represented. Early Cretaceous age is supported for the Gollapalle flora.

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Pang, Li-bo, Shao-kun Chen, Xin Hu, Yan Wu et Guang-biao Wei. « Fossil flying squirrels (Petauristinae, Sciuridae, Rodentia) from the Yumidong Cave in Wushan County, Chongqing, China ». Fossil Record 27, n^o 1 (21 mai 2024) : 209–19. http://dx.doi.org/10.3897/fr.27.e115693.

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Flying squirrels are important forest environment indicators. There have been many reports on them from fossil localities of the Late Cenozoic in southwest China, but relatively few detailed studies have been carried out on them. Numerous flying squirrel fossils of the Mid-Late Pleistocene were unearthed from the Yumidong Cave in Wushan County, Chongqing Municipality, China, providing excellent materials for morphological comparison and further research on this group. Four species have been recognised from this locality, including Pteromys volans, Trogopterus xanthipes, Belomys pearsonii and Aeretes melanopterus. P. volans and A. melanopterus are Palearctic species, which adapted to the cold environment and had been completely extinct in the study area since the Holocene Megathermal period. Based on the analyses of paleozoogeography and paleoecology of these four species, it could be concluded that the Yumidong Cave area was dominated by subalpine evergreen coniferous forest or coniferous and broad-leaved mixed forest during MIS 2 and MIS 4 periods, which were colder and had more coniferous forest than now, while the vegetation landscape of MIS 3 and MIS 5 periods were similar to that of nowadays.

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Gomez, Bernard, Véronique Daviero-Gomez, Géraldine Garcia, Laurent Caner, Anaïs Boura, Abel Barral, Patrice Cantinolle et Xavier Valentin. « Silicified plant megafossils from the upper Turonian of Vienne, western France ». Earth and Environmental Science Transactions of the Royal Society of Edinburgh 108, n^o 4 (décembre 2017) : 449–57. http://dx.doi.org/10.1017/s1755691018000105.

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ABSTRACTA new locality with silicified permineralised plant megafossils is reported from the upper Turonian of Colombiers, Vienne, western France. The plant fossil assemblage consists of Geinitzia reichenbachii (Geinitz) Hollick et Jeffrey and ‘Lomatopteris' superstes Saporta. Whilst G. reichenbachii is a worldwide widespread Cretaceous conifer, ‘L.' superstes is reported in western France for the first time. The latter fossil shows bipinnately compound leaf, marginal teeth, one thick primary vein, pinnate secondary veins and faint, reticulate, narrower veins. Besides its fern-like gross morphology, these characters indicate that it most likely belongs to angiosperms and eudicots. The formation of silicified nodules bearing such fossils from the Cenomanian to the Coniacian of western France was previously attributed to the secondary silicification of limestones during Cenozoic climatic weathering episodes. However, based on both petrography and preservation evidence, we demonstrate that it was an endogenic process contemporaneous to the earliest stages of fossil diagenesis created by palaeoenvironmental and climatic conditions.

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Quamar, Md Firoze, Pooja Tiwari et Biswajeet Thakur. « The modern pollen–vegetation relationship in Jammu, India : a comparative appraisal ». Acta Palaeobotanica 61, n^o 1 (juin 2021) : 1–19. http://dx.doi.org/10.35535/acpa-2021-0001.

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An understanding of the relationship between modern pollen and vegetation is a prerequisite for reconstruction of vegetation and climate change from fossil pollen records. We conducted palynological studies of thirty-five surface soil samples from the Jammu region of India, which revealed that Pinus, among the conifers (regional needle-leaved taxa), is over-represented in the pollen assemblage due to its high production and effective dispersal of pollen. Other coniferous and broadleaved (regional and/or extra-regional) taxa have comparatively lower values in the pollen assemblages, similar to the representation of subtropical deciduous forest elements (regional), as well as shrubby (regional and/or extra-regional) taxa. This inconsistency in the pollen assemblage could be due to long-distance transport of the former by wind and/or water from the higher reaches of the Himalayas, and also because the latter have an entomogamous pollination syndrome and are not high pollen producers. The recovered pollen assemblage presents a distorted picture of the extant vegetation; hence, caution should be exercised in interpreting fossil pollen records from the study area. Principal component analysis (PCA) shows variability in the distribution of pollen from different sites in the Jammu region, perhaps the result of transport (by wind and/ or water), altitude and/or edaphic factors of the Himalayan terrain. The study should improve our understanding of the modern pollen-vegetation relationship and aid further calibration and interpretation of fossil pollen records.

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Carpenter, Raymond J., Jennifer M. Bannister, Daphne E. Lee et Gregory J. Jordan. « Proteaceae leaf fossils from the Oligo - Miocene of New Zealand : new species and evidence of biome and trait conservatism ». Australian Systematic Botany 25, n^o 6 (2012) : 375. http://dx.doi.org/10.1071/sb12018.

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At least seven foliar taxa of Proteaceae occur in Oligo–Miocene lignite from the Newvale site. These taxa include two new species of the fossil genus Euproteaciphyllum, and previously described species of tribe Persoonieae and Banksia. Other specimens from Newvale are not assigned to new species, but some conform to leaves of the New Caledonian genus Beauprea, which is also represented in the lignite by common pollen. Two other Euproteaciphyllum species are described from the early Miocene Foulden Maar diatomite site. One of these species may belong to Alloxylon (tribe Embothrieae) and the other to tribe Macadamieae, subtribe Gevuininae. Ecologically, the species from Newvale represented important components of wet, oligotrophic, open vegetation containing scleromorphic angiosperms and very diverse conifers. In contrast, Proteaceae were large-leaved and rare in Lauraceae-dominated rainforest at the volcanic Foulden Maar site. Overall, the Oligo–Miocene fossils confirm that Proteaceae was formerly much more diverse and dominant in the New Zealand vegetation, and provide fossil evidence for biome conservatism in both leaf traits and lineage representation.

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Rajanikanth, A. « Diversification and evolution of Early Cretaceous East Coast flora of India ». Journal of Palaeosciences 45 (31 décembre 1996) : 369–77. http://dx.doi.org/10.54991/jop.1996.1257.

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The Early Cretaceous continental sediments in the East Coast of India are characterized by the Ptilophyllum flora. Interplay of tectonism and sedimentation caused plant fossil preservation in different unconnected paralic deposits distributed in Cauvery, Palar, Krishna-Godavari and Mahanadi basins and in the associated Pranhita-Godavari Graben. Plant megafossils assigned to pteridophytes, pteridosperms, cycadophytes, Taxales, Ginkgoales and Coniferales are variously distributed in these basins. Differential preservation of plant parts denotes an incomplete evolutionary pattern. Variation within the basinal flora reflects a localised aspect. Plant fossils preserved in the Cauvery, Palar, Krishna-Godavari and Mahanadi basins reflect a near shore continental sedimentary fill subjected to more dynamic events like marine transgression, which probably did not allow better preservation of plant fossils. Paucity of carbonised/silicified material, abundance of impressions of plant leaf fossils, scarcity of wood and reproductive parts indicate an unfavourable environment for plant fossil preservation in these pericratonic basins. Whereas in the associated Pranhita-Godavari Graben the plant fossils are better preserved in the sub-aerially exposed basinal areas away from the main coast-line. The Early Cretaceous flora of Cauvery, Palar and Krishna-Godavari basins dominated by cycadophytes suggests presence of seaward margins of fluviodeltaic palaeoenvironment. The pteridophyte dominant flora of Mahanadi Basin represents a decreasing marine influence contrary towards the south-eastwards. The evolution and diversification of the East Coast Early Cretaceous flora runs parallel to other intracratonic basinal flora. The uniformity in the floral component supports an equable climate. Conifers being the upland floral elements constitute chief components of intracratonic basinal flora. The fluviomarginal elements like cycadophytes predominate the pericratonic sedimentation with some upland near basinal taxa. Pteridosperms and Ginkgoales are scanty. Presence of leaves with entire margin indicates a favourable growth environment.

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Coiro, Mario, Guillaume Chomicki et James A. Doyle. « Experimental signal dissection and method sensitivity analyses reaffirm the potential of fossils and morphology in the resolution of the relationship of angiosperms and Gnetales ». Paleobiology 44, n^o 3 (30 juillet 2018) : 490–510. http://dx.doi.org/10.1017/pab.2018.23.

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AbstractThe placement of angiosperms and Gnetales in seed plant phylogeny remains one of the most enigmatic problems in plant evolution, with morphological analyses (which have usually included fossils) and molecular analyses pointing to very distinct topologies. Almost all morphology-based phylogenies group angiosperms with Gnetales and certain extinct seed plant lineages, while most molecular phylogenies link Gnetales with conifers. In this study, we investigate the phylogenetic signal present in published seed plant morphological data sets. We use parsimony, Bayesian inference, and maximum-likelihood approaches, combined with a number of experiments with the data, to address the morphological–molecular conflict. First, we ask whether the lack of association of Gnetales with conifers in morphological analyses is due to an absence of signal or to the presence of competing signals, and second, we compare the performance of parsimony and model-based approaches with morphological data sets. Our results imply that the grouping of Gnetales and angiosperms is largely the result of long-branch attraction (LBA), consistent across a range of methodological approaches. Thus, there is a signal for the grouping of Gnetales with conifers in morphological matrices, but it was swamped by convergence between angiosperms and Gnetales, both situated on long branches. However, this effect becomes weaker in more recent analyses, as a result of addition and critical reassessment of characters. Even when a clade including angiosperms and Gnetales is still weakly supported by parsimony, model-based approaches favor a clade of Gnetales and conifers, presumably because they are more resistant to LBA. Inclusion of fossil taxa weakens rather than strengthens support for a relationship of angiosperms and Gnetales. Our analyses finally reconcile morphology with molecules in favoring a relationship of Gnetales to conifers, and show that morphology may therefore be useful in reconstructing other aspects of the phylogenetic history of the seed plants.

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Hill, Robert S., et Tim J. Brodribb. « Southern Conifers in Time and Space ». Australian Journal of Botany 47, n^o 5 (1999) : 639. http://dx.doi.org/10.1071/bt98093.

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The three southern conifer families, Araucariaceae, Cupressaceae and Podocarpaceae, have a long history and continue to be an important part of the vegetation today. The Araucariaceae have the most extensive fossil record, occurring in both hemispheres, and with Araucaria in particular having an ancient origin. In the Southern Hemisphere Araucaria and Agathis have substantial macrofossil records, especially in Australasia, and Wollemia probably also has an important macrofossil record. At least one extinct genus of Araucariaceae is present as a macrofossil during the Cenozoic. Cupressaceae macrofossils are difficult to identify in older sediments, but the southern genera begin their record in the Cretaceous (Athrotaxis) and become more diverse and extensive during the Cenozoic. Several extinct genera of Cupressaceae also occur in Cretaceous and Cenozoic sediments in Australasia. The Podocarpaceae probably begin their macrofossil record in the Triassic, although the early history is still uncertain. Occasional Podocarpaceae macrofossils have been recorded in the Northern Hemisphere, but they are essentially a southern family. The Cenozoic macrofossil record of the Podocarpaceae is extensive, especially in south-eastern Australia, where the majority of the extant genera have been recorded. Some extinct genera have also been reported from across high southern latitudes, confirming an extremely diverse and widespread suite of Podocarpaceae during the Cenozoic in the region. In the Southern Hemisphere today conifers achieve greatest abundance in wet forests. Those which compete successfully with broad-leaved angiosperms in warmer forests produce broad, flat photosynthetic shoots. In the Araucariaceae this is achieved by the planation of multiveined leaves into large compound shoots. In the other two families leaves are now limited to a single vein (except Nageia), and to overcome this limitation many genera have resorted to re-orientation of leaves and two-dimensional flattening of shoots. The Podocarpaceae show greatest development of this strategy with 11 of 19 genera producing shoots analogous to compound leaves. The concentration of conifers in wet forest left them vulnerable to the climate change which occurred in the Cenozoic, and decreases in diversity have occurred since the Paleogene in all regions where fossil records are available. Information about the history of the dry forest conifers is extremely limited because of a lack of fossilisation in such environments. The southern conifers, past and present, demonstrate an ability to compete effectively with angiosperms in many habitats and should not be viewed as remnants which are ineffectual against angiosperm competitors.

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Greenwood, David R., Kathleen B. Pigg, James F. Basinger et Melanie L. DeVore. « A review of paleobotanical studies of the Early Eocene Okanagan (Okanogan) Highlands floras of British Columbia, Canada, and Washington, USA ». Canadian Journal of Earth Sciences 53, n^o 6 (juin 2016) : 548–64. http://dx.doi.org/10.1139/cjes-2015-0177.

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The history of plant fossil collecting in the Okanagan (Okanogan) Highlands of British Columbia and northeastern Washington is closely intertwined with the history of geological surveys and mining activities from the 1870s onward. The first descriptions of fossil plants from British Columbia were published in 1870–1920 by J.W. Dawson, G.M. Dawson, and D.P. Penhallow. In the United States, fossil leaves and fish were first recognized at Republic, Washington, by miners in the early 1900s. Many early workers considered these floras to be of Oligocene or Miocene age. C.A. Arnold described Canadian occurrences of conifers and Azolla in the 1950s. Palynological studies in the 1960s by L.V. Hills, G.E. Rouse, and others and those of fossil fish by M.V.H. Wilson in the 1970–1980s provided the framework for paleobotanical research at several key localities. Permineralized plants were first described from the Princeton chert in the 1970s by C.N. Miller, J.F. Basinger, and others, followed by R.A. Stockey and her students. W.C. Wehr and K.R. Johnson revitalized the study of fossils at Republic with the discovery of a diverse assemblage in 1977. In 1987, J.A. Wolfe and Wehr produced a United States Geological Survey monograph on Republic, and Wehr cofounded the Stonerose Interpretive Center as a venue for public collecting. Systematic studies of the Okanagan Highlands plants, as well as paleoecological and paleoclimate reconstructions from palynomorphs and leaf floras, continue to expand our understanding of this important Early Eocene assemblage.

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Donovan, Michael P., Peter Wilf, Ari Iglesias, N. Rubén Cúneo et Conrad C. Labandeira. « Insect herbivore and fungal communities on Agathis (Araucariaceae) from the latest Cretaceous to Recent ». PhytoKeys 226 (26 mai 2023) : 109–58. http://dx.doi.org/10.3897/phytokeys.226.99316.

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Agathis (Araucariaceae) is a genus of broadleaved conifers that today inhabits lowland to upper montane rainforests of Australasia and Southeast Asia. A previous report showed that the earliest known fossils of the genus, from the early Paleogene and possibly latest Cretaceous of Patagonian Argentina, host diverse assemblages of insect and fungal associations, including distinctive leaf mines. Here, we provide complete documentation of the fossilized Agathis herbivore communities from Cretaceous to Recent, describing and comparing insect and fungal damage on Agathis across four latest Cretaceous to early Paleogene time slices in Patagonia with that on 15 extant species. Notable fossil associations include various types of external foliage feeding, leaf mines, galls, and a rust fungus. In addition, enigmatic structures, possibly armored scale insect (Diaspididae) covers or galls, occur on Agathis over a 16-million-year period in the early Paleogene. The extant Agathis species, throughout the range of the genus, are associated with a diverse array of mostly undescribed damage similar to the fossils, demonstrating the importance of Agathis as a host of diverse insect herbivores and pathogens and their little-known evolutionary history.

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Ríos-Santos, César, et Sergio R. S. Cevallos-Ferriz. « Upper Jurassic, Upper Cretaceous and Palaeocene conifer woods from Mexico ». Earth and Environmental Science Transactions of the Royal Society of Edinburgh 108, n^o 4 (décembre 2017) : 399–418. http://dx.doi.org/10.1017/s1755691018000245.

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ABSTRACTAlthough there are reports of permineralised woods in Mesozoic and Cenozoic strata in Mexico, there are few palaeobotanical studies based on coniferous stems. Four taxa of fossil wood from three localities in Mexico are described at the anatomical level and identified taxonomically based on detailed comparisons with woods of extant and fossil taxa. Agathoxylon gilii sp. nov. and A. jericonse sp. nov. are determined from the Todos Santos Formation (Upper Jurassic), in Chiapas; A. parrensis sp. nov. is described from the Las Encinas Formation (Palaeocene) in Coahuila; and Taxodioxylon cabullensis sp. nov. corresponds with material from the Packard Shale Formation in Sonora. Dominance of Araucariaceae and Cupressaceae in this region during the Mesozoic and early Cenozoic is further supported by leaf records, but these materials may also represent other taxa, like Cheirolepidaceae, which may have araucarioid secondary xylem. Records of Brachyphyllum and/or Pagiophyllum, which may represent araucarioid or cheirolepidaceous taxa, and different cupressaceous leaves, have been collected in rocks of the same period in nearby formations. At present, the amalgamation of isolated organs to form one plant is uncertain and, thus, there is an open challenge to reconstruct the plants and better understand these extinct communities. The new fossil taxa will add to the diversity of extinct plants and conifer communities during the Mesozoic and early Cenozoic in low-latitude North America.

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Kustatscher, Evelyn, Giovanni G. Scanu, Jiří Kvaček et Johanna H. A. Van Konijnenburg-van Cittert. « The Krasser collection In the Faculty of Sciences, Charles University, Prague – New insights into the Middle Jurassic flora of Sardinia ». Fossil Imprint 72, n^o 3-4 (30 décembre 2016) : 140–54. http://dx.doi.org/10.14446/fi.2016.140.

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Revision of part of the Middle Jurassic flora of Sardinia, the Krasser collection, stored in Prague (Lovisato B collection), containing 23 fossil taxa of horsetails, ferns, cycadophytes, ginkgophytes and conifers. The conifers are most diverse, followed by cycadophytes and ferns. The composition of this assemblage differs notably from the Lovisato collection stored in Cagliari, suggesting that it might derive from a different stratigraphic level and/or palaeoenvironment. The palaeodiversity of the Middle Jurassic flora of Sardinia increases to 46 fossil taxa with this revision. Cycadolepis sp. Nilssonia sp., Nilssonia sp. cf. N. orientalis, Pagiophyllum sp. and Agathoxylon sp. are described for the first time from the Middle Jurassic of Sardinia.

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Royer, Dana L., Kylen M. Moynihan, Melissa L. McKee, Liliana Londoño et Peter J. Franks. « Sensitivity of a leaf gas-exchange model for estimating paleoatmospheric CO2 ; concentration ». Climate of the Past 15, n^o 2 (17 avril 2019) : 795–809. http://dx.doi.org/10.5194/cp-15-795-2019.

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Abstract. Leaf gas-exchange models show considerable promise as paleo-CO2 proxies. They are largely mechanistic in nature, provide well-constrained estimates even when CO2 is high, and can be applied to most subaerial, stomata-bearing fossil leaves from C3 taxa, regardless of age or taxonomy. Here we place additional observational and theoretical constraints on one of these models, the “Franks” model. In order to gauge the model's general accuracy in a way that is appropriate for fossil studies, we estimated CO2 from 40 species of extant angiosperms, conifers, and ferns based only on measurements that can be made directly from fossils (leaf δ13C and stomatal density and size) and on a limited sample size (one to three leaves per species). The mean error rate is 28 %, which is similar to or better than the accuracy of other leading paleo-CO2 proxies. We find that leaf temperature and photorespiration do not strongly affect estimated CO2, although more work is warranted on the possible influence of O2 concentration on photorespiration. Leaves from the lowermost 1–2 m of closed-canopy forests should not be used because the local air δ13C value is lower than the global well-mixed value. Such leaves are not common in the fossil record but can be identified by morphological and isotopic means.

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Uhl, Dieter, et André Jasper. « Charred conifer remains from the Late Oligocene – Early Miocene of Northern Hesse (Germany) ». Acta Palaeobotanica 58, n^o 2 (1 décembre 2018) : 175–84. http://dx.doi.org/10.2478/acpa-2018-0012.

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AbstractFire is an important constituent of many modern and fossil ecosystems. During the last decades a large number of studies have dealt with fires in pre-Cenozoic ecosystems. Evidence for the occurrence of Palaeogene and Neogene wildfires (e.g. in the form of pyrogenic inertinites in lignite deposits) is geographically and stratigraphically widespread. However, as compared to earlier periods (i.e. the Permian and Cretaceous), fewer studies have focussed so far on plants burnt (or charred) in wildfires from these periods, even though these periods are of considerable interest for our understanding of the evolution of modern ecosystems. Here we report the occurrence of charred wood remains belonging to different conifer taxa from the base seam of the former Frielendorf opencast lignite mine in Northern Hesse (Germany). These findings are evidence that these conifers, and the types of vegetation they were growing in, were affected by wildfires occurring during the Late Oligocene – Early Miocene in this region.

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Wilf, Peter. « From Patagonia to Indonesia : plant fossils highlight West Gondwanan legacy in the Malesian flora ». Berita Sedimentologi 47, n^o 3 (28 décembre 2021) : 81–82. http://dx.doi.org/10.51835/bsed.2021.47.3.367.

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Rainforests with the chinquapin Castanopsis and the yellowwood conifer Dacrycarpus occur today throughout Indonesia and the larger Malesian ecoregion, but they represent, in part, a history of survival stretching tens of millions of years and thousands of kilometers to the palaeo-Antarctic. Unlike New World and African tropical rainforests, the Malesian flora’s history is closely tied to tectonic introductions from exotic terranes, and thus, much palaeobotanical data about the origins of the Malesian rainforest comes from those terranes. For example, South America, Antarctica, and Australia remained adjacent until the Eocene final separation of Gondwana, and warm climates promoted high-latitude dispersals among those landmasses. Australia’s subsequent northward movement led to the late Oligocene Sahul-Sunda collision and the uplift of New Guinea, allowing the introductions into Malesia of survivor taxa that were once widespread in mesic Gondwanan rainforests. In Patagonian Argentina, the prolific Laguna del Hunco (52.2 Ma) site preserves abundant and well-preserved fossils of an unexpectedly large number of lineages whose living relatives characteristically associate in perhumid, lower montane “oak-laurel” rainforests of Malesia, especially in New Guinea. These taxa include the angiosperms Castanopsis (Fagaceae), Gymnostoma (rhu, Casuarinaceae), Alatonucula (extinct engelhardioid Juglandaceae), Eucalyptus (gums, Myrtaceae), Ceratopetalum (coachwood, Cunoniaceae), Lauraceae (laurel family), and Ripogonum (supplejack, Ripogonaceae); conifers in Cupressaceae (cypress family: Papuacedrus), Araucariaceae (dammars and relatives: Agathis and Araucaria Section Eutacta), and Podocarpaceae (yellowwoods: Dacrycarpus, Podocarpus, and a species similar to Phyllocladus); and the fern Todea (king fern, Osmundaceae). Many of these records are the only occurrences of the respective taxa in South America, living or fossil, vastly extending their past ranges and thus the biogeographic history of part of the Malesian mountain flora. The living-fossil taxa inhabit, and several dominate, critical watershed areas of high endemism and biodiversity in Malesia’s endangered tropical-montane rainforests. In Malesia itself, there have been very few Cenozoic palaeobotanical investigations for about a century or more. To remedy this situation and improve understanding of the evolution of the Malesian flora in situ, we have begun palaeobotanical fieldwork in collaboration with Professor Yahdi Zaim and ITB, along with international colleagues. So far, we have discovered several promising new fossil sites in the Eocene-Oligocene of West Sumatra (Sangkarewang and Sawahlunto formations) and South Kalimantan (Tanjung Formation), and I will report preliminary observations.

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Czaplewski, Nicholas J. « First report of bats (Mammalia : Chiroptera) from the Gray Fossil Site (late Miocene or early Pliocene), Tennessee, USA ». PeerJ 5 (27 avril 2017) : e3263. http://dx.doi.org/10.7717/peerj.3263.

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Thousands of vertebrate fossils have been recovered from the Gray Fossil Site, Tennessee, dating to the Miocene-Pliocene boundary. Among these are but eight specimens of bats representing two different taxa referable to the family Vespertilionidae. Comparison of the fossils with Neogene and Quaternary bats reveals that seven of the eight specimens pertain to a species of Eptesicus that cannot be distinguished from recent North American Eptesicus fuscus. The remaining specimen, a horizontal ramus with m3, is from a smaller vespertilionid bat that cannot confidently be assigned to a genus. Although many vespertilionid genera can be excluded through comparisons, and many extinct named taxa cannot be compared due to nonequivalence of preserved skeletal elements, the second taxon shows morphological similarities to small-bodied taxa with three lower premolar alveoli, three distinct m3 talonid cusps, and m3 postcristid showing the myotodont condition. It resembles especially Nycticeius humeralis and small species of Eptesicus. Eptesicus cf. E. fuscus potentially inhabited eastern North America continuously since the late Hemphillian land mammal age, when other evidence from the Gray Fossil Site indicates the presence in the southern Appalachian Mountains of a warm, subtropical, oak-hickory-conifer forest having autochthonous North American as well as allochthonous biogeographical ties to eastern Asia and tropical-subtropical Middle America.

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Bhatt, Nishith Y., Paras M. Solanki, Neeru Prakash et Neelam Das. « Depositional environment of Himmatnagar Sandstone (Lower/Middle Cretaceous) : a perspective ». Journal of Palaeosciences 65, n^o (1-2) (31 décembre 2016) : 67–84. http://dx.doi.org/10.54991/jop.2016.300.

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Himmatnagar Sandstone (lower to middle Cretaceous) is exposed in between Sabarmati River in the west to Vantada in the east around Himmatnagar Town in north Gujarat, India. The sequence is divisible in two members: The lower member is 65 m thick, mostly massive, horizontally stratified to hummocky stratified with abundant plant and trace fossils in assorted shales and sandstones. The upper member is ~ 12 m thick, cross–stratified and medium to coarse grained–gritty to cobbly in nature. Six lithofacies have been identified in the sequence, viz. 1. grey wacke (GW), 2. silty–shale (SS), 3. cross–stratified sandstone (CS), 4. horizontally stratified sandstone (HSS), and 5. planar cross–stratified sandstone (PCS) in the lower member; and 6. gritty–cobbly cross–stratified sandstone (GCCS) in the upper member. The lower member consists of plant fossils which are poor to moderately preserved and transported. The silty–shale lithofacies contains plant fossils (Pagiophyllum, Brachyphyllum, Gleichenia, Araucarites, circinate vernation of ferns, Williamsonia flower, twigs, petrified wood, conifer and its cone, etc.), body fossil (insect wing) and trace fossils (Skolithos, Monocraterion, Psilonichnus, Thalassinoides, Chondrites, Planolites, Palaeophycus, Calycraterion, Circulichnus, Ophiomorpha, Phoebichnus, etc.). In the cross–stratified sandstone lithofacies, body fossils (mainly fragmented bivalves, plant fossils (Weichselia reticulata, Matonidium indicum, Ptilophyllum, cycadean frond and fossil wood) and trace fossils (Monocraterion, Chondrites, Calycraterion, Thalassinoides, Psilonichnus and Skolithos) are recognized. On the other hand, in horizontally stratified sandstone lithofacies plant fossils (Sphenopteris, Pagiophyllum, Gleichenia, Elactocladus, Brachyphyllum, ferns, petrified wood, etc.) and trace fossils (Skolithos, Ophiomorpha, Psilonichnus, Monocraterion, Arenicolites, Diplocraterion, Thalassinoides, Teichichnus, Palaeophycus, Planolites, etc.) are present. While, large crustacean and vertebrate burrows, Skolithos, Thalassinoides, Ophiomorpha, etc are found in planar cross–stratified sandstone lithofacies. The trace fossils belong to Psilonichnus, Skolithos and Cruziana ichnofacies as per Seilacher (1967). The member also contains wedge shape geometry of beds similar to tidal partings as well as ridge and runnel structures, low–angle to hummocky cross–stratification, herringbone structure and parting lineation. Here, north to northeast palaeo–current direction is indicated by cross–stratification in the member. All these features lead to the depositional environment, which seems to be foreshore–tidal flat to middle shoreface for the lower member of the sequence. The upper member is composed of trough cross–stratified sandstones showing prominently southwest to south palaeo–current direction with angular to sub–rounded pebbles and cobbles of underlying rocks and fossil wood with lower erosional contact and channel structures at places. Based on above characteristics, depositional environment of upper member can be interpreted from estuarine to fluvial.

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Lacourse, Terri, Rolf W. Mathewes et Daryl W. Fedje. « Paleoecology of late-glacial terrestrial deposits with in situ conifers from the submerged continental shelf of western Canada ». Quaternary Research 60, n^o 2 (septembre 2003) : 180–88. http://dx.doi.org/10.1016/s0033-5894(03)00083-8.

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AbstractExtensive portions of the continental shelf off the coast of British Columbia were subaerially exposed during Late Wisconsinan deglaciation due to lowering of relative sea level by as much as 150 m. Paleoecological analyses were conducted at two sites on the emergent continental shelf where terrestrial surfaces with in situ conifers are preserved. The woody plant remains confirm that, during the latest period of subaerial exposure, terrestrial vegetation was established on the continental shelf. Microscopic identification of fossil wood, and analyses of pollen and plant macrofossils from the associated paleosols and overlying shallow pond sediments indicate that productive Pinus contorta-dominated communities with abundant Alnus crispa and ferns grew on the shelf adjacent to and on the Queen Charlotte Islands around 12,200 14C yr B.P. Dwarf shrubs including Salix and Empetrum, and herbaceous plants such as Heracleum lanatum and Hippuris vulgaris, were also important components of the shelf vegetation. Near northern Vancouver Island, mixed coniferous forests dominated by Pinus contorta with Picea, Tsuga spp., Alnus spp., and ferns occupied the shelf at 10,500 14C yr B.P.

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Cichan, Michael A. « Conductance in the wood of selected Carboniferous plants ». Paleobiology 12, n^o 3 (1986) : 302–10. http://dx.doi.org/10.1017/s0094837300013804.

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Specific conductance was calculated for secondary xylem in seven Carboniferous stem taxa utilizing an equation derived from the Hagen-Poiseuille relation. Arborescent and lianoid representatives of major pteridophytic (Calamitaceae, Lepidodenraceae, Sphenophyllaceae) and gymnospermous (Cordaitaceae, Medullosaceae) groups were examined. In the calamite Arthropitys communis and the seed plant Cordaites (Cordaixylon sp. and Mesoxylon sp.), conductance corresponded approximately to the low end of the range for both extant conifers and angiosperms. A substantially higher conductance was determined for the wood of Arthropitys deltoides, conforming to the high end of the range for conifers and the low-middle part of the range for angiosperms. The highest conductance values were found in Sphenophyllum plurifoliatum, Medullosa noei, and Paralycopodites brevifolius and corresponded to the middle-high portion of the range for vessel-containing angiosperms. This outcome is particularly significant in light of the fact that tracheary elements in the fossils are imperforate. The results indicate that conductance in secondary xylem of some of the most ancient, woody groups was comparable to that in extant plants and that highly effective conducting tissue developed relatively early in plant evolution. Moreover, it is suggested that the general relationship between wood anatomy, growth habit, and ecology demonstrated for living plants can also be extended back in time to include fossil plants.

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Pott, Christian, et Baoyu Jiang. « Plant remains from the Middle–Late Jurassic Daohugou site of the Yanliao Biota in Inner Mongolia, China ». Acta Palaeobotanica 57, n^o 2 (1 décembre 2017) : 185–222. http://dx.doi.org/10.1515/acpa-2017-0012.

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AbstractA late Middle–early Late Jurassic fossil plant assemblage recently excavated from two Callovian–Oxfordian sites in the vicinity of the Daohugou fossil locality in eastern Inner Mongolia, China, was analysed in detail. The Daohugou fossil assemblage is part of the Callovian–Kimmeridgian Yanliao Biota of north-eastern China. Most major plant groups thriving at that time could be recognized. These include ferns, caytonialeans, bennettites, ginkgophytes, czekanowskialeans and conifers. All fossils were identified and compared with species from adjacent coeval floras. Considering additional material from three collections housed at major palaeontological institutions in Beijing, Nanjing and Pingyi, and a recent account in a comprehensive book on the Daohugou Biota, the diversity of the assemblage is completed by algae, mosses, lycophytes, sphenophytes and putative cycads. The assemblage is dominated by tall-growing gymnosperms such as ginkgophytes, czekanowskialeans and bennettites, while seed ferns, ferns and other water- or moisture-bound groups such as algae, mosses, sphenophytes and lycophytes are represented by only very few fragmentary remains. The floral composition underlines the Callovian–Kimmeridgian age of the Yanliao Biota. The Daohugou/Yanliao flora is a typical member of the Middle to Late JurassicConiopteris-Phoenicopsisassemblage of north-eastern China, differing from the Early Cretaceous Jehol flora. Both floras probably belong to the same cycle of volcanism and sedimentation, although the Daohugou Bed is older than the Yixian Formation. The Yanliao fossil assemblage is placed in a larger palaeo-phytogeographical context and its relationships with Middle–Late Jurassic floras from north-eastern China, north-eastern and eastern Siberia and Japan are evaluated.

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Carpenter, Raymond J., Matthew P. Goodwin, Robert S. Hill et Karola Kanold. « Silcrete plant fossils from Lightning Ridge, New South Wales : new evidence for climate change and monsoon elements in the Australian Cenozoic ». Australian Journal of Botany 59, n^o 5 (2011) : 399. http://dx.doi.org/10.1071/bt11037.

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Diverse Cenozoic (possibly latest Oligocene to mid–late Miocene) macrofossils from the Lightning Ridge opal fields are illustrated and discussed. Specimens identified to, or closely comparable with, extant taxa include ferns (Lygodium, Gleichenia and others), conifers now extinct in Australia (Dacrydium, Retrophyllum and Papuacedrus), Lauraceae (Cryptocarya/Cinnamomum), sclerophyllous Proteaceae (Banksia, Lomatia and Grevillea), Cunoniaceae/Elaeocarpaceae and Eucalyptus (and/or other Myrtaceae). Overall, at least four fern, three conifer and 30 angiosperm taxa are recognised. The climate supported many species with close relatives in wet Australasian habitats, including rainforests. However, a drier or more seasonal (?monsoonal) aspect is especially indicated by the presence of lobed leaves that resemble extant species of Brachychiton (Malvaceae), Erythrina (Fabaceae) and tribe Cercideae (Fabaceae). A degree of water stress is also suggested by the prevalence of narrow, toothed and/or deeply lobed angiosperm leaves.

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