Search results for "LAND"
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Paleohistology of the Cretaceous resin‐producing conifer Geinitzia reichenbachii using X‐ray synchrotron microtomography
2021
International audience; PremiseThe conifer Geinitzia reichenbachii was a common member of the Cretaceous Laurasian floras. However, the histology of G. reichenbachii leafy axes was never described in detail, and our knowledge of its paleoecology remains very limited. Using new and exquisitely preserved silicified material from the Upper Cretaceous of western France, we describe G. reichenbachii from the gross morphology to the cellular scale, then discuss paleoecological and taphonomical implications.MethodsWe examined specimens from two localities in western France (Claix and Moragne) using propagation phase-contrast X-ray synchrotron microtomography.ResultsThe cuticle and the inner tissue…
Tendencies in paleontological practice when defining species, and consequences on biodiversity studies
2005
The exploration of evolutionary patterns over geological time has recently received new impetus from the development of morphological disparity as a new biodiversity metric alongside taxonomic diversity. Clade dynamics can be analyzed by comparing and contrasting these two metrics. Like any metrics based on sampling, quantification, and naming, taxonomic diversity and morphological disparity are not free from bias. The long use of taxonomic diversity has prompted many studies of bias and its effects, whereas bias affecting morphological disparity has only been summarily explored. This is particularly so for the effect of the growth of knowledge over paleontographical time (i.e., historical …
Albian flora from Archingeay-Les Nouillers (Charente-Maritime): comparison and synthesis of Cretaceous meso- and macro-remains from the Aquitaine Bas…
2017
International audience; Over recent decades, diverse structures ascribed to angiosperms, bennettitaleans, conifers, cycads, ginkgophytes and pteridosperms have been reported from the Cretaceous deposits of the Aquitaine Basin (southwestern France). However, Albian macrofloras remain uncommon in Aquitania as well as in France. The clay from the Archingeay-Les Nouillers quarries is one of the rare deposits of the Aquitaine Basin to yield Albian plant meso- and macro-remains. Although Albian plant-bearing beds are not accessible any more in these quarries, samples collected from excavations conducted at the end of the XXth century were deposited in the collections of the University of Rennes 1…
Flore turonienne des silex fossilifères de Châtellerault (Ouest de la France)
2018
International audience; Three new localities yielding fossiliferous flints are reported from the Châtellerault area (Vienne, western France). They include one archaeological site (La Grande Vallée) and two zones with alterite deposits (L’Aunas and Les Bariollières). Broken surfaces of flint nodules show co-occurrence of marine invertebrates such as bryozoans, echinoids (Micraster Agassiz, Orthopsis Cotteau), gastropods (Acteonella d’Orbigny), rudists, and sponges. The association of Acteonella, Micraster and Orthopsis confirms the Turonian age (Upper Cretaceous) of the fossil assemblage. The marine invertebrates co-occur with plant macroremains including fragments of conifer leafy axes such…
Conifers from the Cenomanian amber of Fouras (Charente-Maritime, western France)
2020
Fossil inclusions of arthropods and microorganisms are abundant in the Cretaceous amber from western France, but plant meso- or macroremains are scarce. Preserved remains are mostly tiny, very fragmented, and indeterminable. Only one amber locality in the Charente department has already provided conifer remains. Here, we report the first plant mesoremains ensnared in Cenomanian amber from Fouras – Bois Vert, in the Charente-Maritime department. They consist of three well-preserved leafy axes and one cone of Cheirolepidiacean conifers. Based on the helical arrangement of rhomboidal, longer than wide, and highly adpressed leaves, leafy axes are ascribed to the genus Pagiophyllum. The ovoid co…
Synthèse sur la diversité des préservations végétales du site d’Archingeay-Les Nouillers (France) : un Konservat-Lagerstätte pour les flores de l’Alb…
2017
Since the end of the XXth century, the palaeontological site of Archingeay-Les Nouillers (Charente-Maritime, western France) continued to afford Albian-Cenomanian (ca 93–113 Ma) plant meso- and macroremains. The successive excavations provided numerous specimens useful for the reconstruction of mid-Cretaceous coastal forest ecosystems. However, one of the most remarkable features of this locality is the diversity of plant preservations. Unique in Europe from this point of view, the fossiliferous site of Archingeay-Les Nouillers yielded compressions with or without cuticle, impressions/imprints, and silicified permineralizations/petrifications. The quality of the silicified tissues and the c…
Trackways of Arthropleura from the Late Pennsylvanian of Graissessac (Hérault, southern France)
2019
International audience; The Late Pennsylvanian deposits of the Graissessac Basin (southern France) are well known for their abundant and diversified plant remains. Here we report on seven trackways of giant millipede-like arthropods recently discovered from two surfaces. These traces are ascribed to Diplichnites cuithensis. The trackways are up to 200 cm long, up to 36 cm wide, straight to curved and consist of two parallel rows of numerous and elongated appendage imprints that are oriented perpendicular to the midline. Although body fossils of giant millipede-like arthropods remain unknown in sediments from this basin, the morphology and size of the trace fossils indicate that the trails w…
Étude paléobotanique d’une lentille argileuse cénomanienne de la carrière de Hucheloup, Maine-et-Loire, NO France : implications taxonomiques, strati…
2017
International audience; A Cenomanian clay lens in Hucheloup Quarry (Maine-et-Loire, north-western France) has yielded 82 foliar compressions and impressions, of which 62 were identified at several taxonomic levels. The plants are ascribed to diverse Pinales (27%), ferns (27%), Ginkgoales (26%), angiosperms (19%) and Cycadales (1%). The most abundant species in the assemblage are Frenelopsis alata (K. Feistmantel) E. Knobloch emend. J. Kvaček (Pinales) and Eretmophyllum obtusum (Velenovský) J. Kvaček (syn. E. andegavense Pons, Bourreau et Broutin) (Ginkgoales). Wood fragments, along with very well-preserved cuticles, have also been recovered and identified. The specimens are usually very fra…
Comment on the letter of the Society of Vertebrate Paleontology (SVP) dated April 21, 2020 regarding “Fossils from conflict zones and reproducibility…
2020
International audience
Arable-weed flora and its pollen representation: A case study from the eastern part of France
2007
International audience; Local pollen deposition in human-influenced vegetation types is studied with the aim of establishing the relationship between arable-weed vegetation and its pollen representation as an aid in interpreting human presence and impact on vegetation from pollen assemblages. The study area is located in the Franche-Comté region, eastern part of France. The presence of plants within 100 m2 plots and their pollen representation in moss samples within the same plots was recorded from different crops and annual fallows. Patterns in the vegetation and pollen assemblages were investigated separately using principal coordinate analysis (PCoA). Procrustean co-inertia analysis (PCI…