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Yongdong Wang - One of the best experts on this subject based on the ideXlab platform.
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Cuticle ultrastructure of Baiera furcata from Northeast China and its implication in taxonomy and paleoenvironment
Review of Palaeobotany and Palynology, 2019Co-Authors: Gaetan Guignard, Xiaoju Yang, Yongdong WangAbstract:Abstract A study on the leaf cuticle ultrastructures of Baiera furcata from the Lower Cretaceous Huolinhe Formation in East Inner Mongolia, Northeast China, was conducted with transmission electron microscopy (TEM) and elements analysis by Energy Dispersive Spectroscopy (EDS). TEM observation revealed the ultrastructural details from ordinary epidermal cells for both upper and lower cuticles, and stomatal apparatus, which were all made with A2 (granular) and B1 (fibrilous) layers. Additionally, well-preserved cell remnants were also observed. Comparisons with other cuticles of the Ginkgoales were made using statistical measurements and evaluations of some potential Order characteristics, and genus–species characteristics were also emphasized. Two potential ultrastructural groups can be recognized: Baiera–Sphenobaiera and Ginkgo–Ginkgoites–Pseudotorellia. This is reinforced by EDS element analysis, whereby ratios could also be compared with another closely related Ginkgoalean taxon Sphenobaiera huangii. The paleoenvironment significances is discussed, and it seems to support the TEM and EDS results. It indicates a signature in the cuticle fine details of Sphenobaiera, which has experienced a putatively warmer paleoenvironment than that of Baiera.
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A Jurassic wood providing insights into the earliest step in Ginkgo wood evolution
Scientific Reports, 2016Co-Authors: Zikun Jiang, Marc Philippe, Yongdong Wang, Wu Zhang, Ning Tian, Shaolin ZhengAbstract:The fossil record of Ginkgo leaf and reproductive organs has been well dated to the Mid-Jurassic (170 Myr). However, the fossil wood record that can safely be assigned to Ginkgoales has not yet been reported from strata predating the late Early Cretaceous (ca. 100 Myr). Here, we report a new fossil wood from the Mid-Late Jurassic transition deposit (153–165 Myr) of northeastern China. The new fossil wood specimen displays several Ginkgo features, including inflated axial parenchyma and intrusive tracheid tips. Because it is only slightly younger than the oldest recorded Ginkgo reproductive organs (the Yima Formation, 170 Myr), this fossil wood very probably represents the oldest bona fide fossil Ginkgo wood and the missing ancestral form of Ginkgo wood evolution.
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Occurrences of Early Cretaceous fossil woods in China: Implications for paleoclimates
Palaeogeography Palaeoclimatology Palaeoecology, 2013Co-Authors: Xiaoju Yang, Yongdong Wang, Wu ZhangAbstract:article i nfo The Chinese Early Cretaceous flora was divided phytogeographically into the Northern Floristic Province and the Southern Floristic Province. The "temperate-wet vegetations" and "tropic-subtropic xeric vegetations" were proposed to represent the two different vegetation types. About 52 species of fossil woods belonging to Cycadophytes (2 species), Ginkgoales (1 species) and coniferales (49 species) have been discovered in the two floristic provinces, mainly from the Northeast China. The biodiversity and anatomical characteristics, espe- cially the growth ring feature analysis of fossil woods indicated climatic conditions with seasonal variation in both the Northern and Southern Floristic Provinces during the Early Cretaceous. It suggests that a tropic to sub-tropic semi-arid climate might dominate over southern China, while warm or temperate, and wet climate prevailed in northern China during the Early Cretaceous. The wood evidence is in accordance with that of the leaf fossils collected from the corresponding formations of the Early Cretaceous in China.
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Cuticular anatomy of Sphenobaiera huangii (Ginkgoales) from the Lower Jurassic of Hubei, China.
American journal of botany, 2005Co-Authors: Yongdong Wang, Gaetan Guignard, Frédéric Thévenard, David L. Dilcher, Georges Barale, Volker Mosbrugger, Xiaoju Yang, Shengwu MeiAbstract:Sphenobaiera huangii (Sze) Hsu is typical Early Mesozoic fossil foliage of Ginkgoales in China. It has been recorded from the Upper Triassic to the Lower Jurassic. The cuticular anatomy is investigated based on material from the type locality, Lower Jurassic Hsiangchi Formation, Zigui County, Hubei Province. The specimens are similar to S. huangii, but contain new information about leaf morphology and cuticular anatomy. Lower and upper cuticle is investigated using light and electron microscopy (LM, SEM, and TEM). Many features are described for the first time, including general structures of lower and upper cuticle, stomata, papillae, and cuticular ultrastructure. At the ultrastructural level, two layers have been distinguished in both lower and upper cuticle, including a homogeneous outer layer with granules and a heterogeneous inner layer with fibrils. Based on a literature comparison between S. huangii and other relevant species of Sphenobaiera, S. huangii may represent the best-known taxon in the genus Sphenobaiera in both leaf morphology and cuticular structures. This study provides the first detailed ultrastructural data on the leaf cuticle of Sphenobaiera, one of the oldest foliage taxa of Ginkgoales, and offers further evidence for potential discussion on the taxonomic relationships of S. huangii with other ginkgoalean taxa.
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CUTICULAR ANATOMY OF SPHENOBAIERA HUANGII (Ginkgoales) FROM THE LOWER JURASSIC
2005Co-Authors: Yongdong Wang, David L. Dilcher, Georges Barale, Volker Mosbrugger, Xiaoju Yang, Shengwu MeiAbstract:Sphenobaiera huangii (Sze) Hsuis typical Early Mesozoic fossil foliage of Ginkgoales in China. It has been recorded from the Upper Triassic to the Lower Jurassic. The cuticular anatomy is investigated based on material from the type locality, Lower Jurassic Hsiangchi Formation, Zigui County, Hubei Province. The specimens are similar to S. huangii, but contain new information about leaf morphology and cuticular anatomy. Lower and upper cuticle is investigated using light and electron microscopy (LM, SEM, and TEM). Many features are described for the first time, including general structures of lower and upper cuticle, stomata, papillae, and cuticular ultrastructure. At the ultrastructural level, two layers have been distinguished in both lower and upper cuticle, including a homogeneous outer layer with granules and a heterogeneous inner layer with fibrils. Based on a literature comparison between S. huangii and other relevant species of Sphenobaiera, S. huangii may represent the best-known taxon in the genus Sphenobaiera in both leaf morphology and cuticular structures. This study provides the first detailed ultrastructural data on the leaf cuticle of Sphenobaiera, one of the oldest foliage taxa of Ginkgoales, and offers further evidence for potential discussion on the taxonomic relationships of S. huangii with other ginkgoalean taxa.
Shaolin Zheng - One of the best experts on this subject based on the ideXlab platform.
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A Jurassic wood providing insights into the earliest step in Ginkgo wood evolution
Scientific Reports, 2016Co-Authors: Zikun Jiang, Marc Philippe, Yongdong Wang, Wu Zhang, Ning Tian, Shaolin ZhengAbstract:The fossil record of Ginkgo leaf and reproductive organs has been well dated to the Mid-Jurassic (170 Myr). However, the fossil wood record that can safely be assigned to Ginkgoales has not yet been reported from strata predating the late Early Cretaceous (ca. 100 Myr). Here, we report a new fossil wood from the Mid-Late Jurassic transition deposit (153–165 Myr) of northeastern China. The new fossil wood specimen displays several Ginkgo features, including inflated axial parenchyma and intrusive tracheid tips. Because it is only slightly younger than the oldest recorded Ginkgo reproductive organs (the Yima Formation, 170 Myr), this fossil wood very probably represents the oldest bona fide fossil Ginkgo wood and the missing ancestral form of Ginkgo wood evolution.
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Morphology and age of Yimaia (Ginkgoales) from Daohugou Village, Ningcheng, Inner Mongolia, China
Cretaceous Research, 2007Co-Authors: Zhi-yan Zhou, Shaolin Zheng, Lijun ZhangAbstract:Abstract New ginkgoalean ovulate organs of Yimaia type were found in the fossil-bearing bed of the village of Daohugou, Ningcheng, Inner Mongolia. They generally resemble other species of Yimaia and some detached seeds described under the morphogeneric name Allicospermum from the Lower and Middle Jurassic in shape and size of ovules, but are markedly distinguished by the cuticular structure of the integument. The ultrastructure of the megaspore membrane and the associated leaves also differ from those known in comparable taxa. Ginkgoalean leaves found in the Daohugou bed are mainly of the Ginkgoites type, some of which are still attached to the shoots. They may be classified in three morphotypes. Leaves of Ginkgoites Morphotype 1, which are most abundant and closely associated with Yimaia , probably belong to the same plant. The presence of the Jurassic element Yimaia supports the opinion of some invertebrate palaeontologists that the Daohugou bed is of Jurassic (most probably mid Jurassic) age. In floristic composition, the Daohugou plant assemblage differs from the early Cretaceous Jehol flora, but closely resembles the Middle Jurassic flora of northeast China.
Frédéric Thévenard - One of the best experts on this subject based on the ideXlab platform.
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A reappraisal of Lignier's Mesozoic fossil wood collection: Ages, nomenclature and taxonomy
Review of Palaeobotany and Palynology, 2018Co-Authors: Marc Philippe, M. Rioult, J.-ph. Rioult, Frédéric ThévenardAbstract:Abstract In 1907 the French palaeobotanist Octave Lignier published a study of Jurassic fossil wood that was to become a seminal palaeoxylological work. Although the names he established were often used or recombined and his contribution is still often quoted today, the original material was never re-studied, except for one of the fifteen originally published samples. This material was only recently been rediscovered, after it was thought to be lost since the 1980s. Here we make use of this opportunity to re-evaluate stratigraphical attributions and ages of Lignier's original samples, to review their nomenclatural status and discuss their taxonomical assignment. Three new combinations are introduced: ( Agathoxylon tranchantii (Lignier) comb. nov., Baieroxylon divesence (Lignier ex Seward) comb. nov., Brachyoxylon blevillense (Lignier) comb. nov.), and a new species ( Agathoxylon crasseradiatum sp. nov.) is published based on Lignier's material. Baieroxylon divesence is anatomically closely related to modern ginkgo and hence an interesting milestone is the little documented history of Ginkgoales wood.
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Cuticular anatomy of Sphenobaiera huangii (Ginkgoales) from the Lower Jurassic of Hubei, China.
American journal of botany, 2005Co-Authors: Yongdong Wang, Gaetan Guignard, Frédéric Thévenard, David L. Dilcher, Georges Barale, Volker Mosbrugger, Xiaoju Yang, Shengwu MeiAbstract:Sphenobaiera huangii (Sze) Hsu is typical Early Mesozoic fossil foliage of Ginkgoales in China. It has been recorded from the Upper Triassic to the Lower Jurassic. The cuticular anatomy is investigated based on material from the type locality, Lower Jurassic Hsiangchi Formation, Zigui County, Hubei Province. The specimens are similar to S. huangii, but contain new information about leaf morphology and cuticular anatomy. Lower and upper cuticle is investigated using light and electron microscopy (LM, SEM, and TEM). Many features are described for the first time, including general structures of lower and upper cuticle, stomata, papillae, and cuticular ultrastructure. At the ultrastructural level, two layers have been distinguished in both lower and upper cuticle, including a homogeneous outer layer with granules and a heterogeneous inner layer with fibrils. Based on a literature comparison between S. huangii and other relevant species of Sphenobaiera, S. huangii may represent the best-known taxon in the genus Sphenobaiera in both leaf morphology and cuticular structures. This study provides the first detailed ultrastructural data on the leaf cuticle of Sphenobaiera, one of the oldest foliage taxa of Ginkgoales, and offers further evidence for potential discussion on the taxonomic relationships of S. huangii with other ginkgoalean taxa.
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Assemblages floristiques de l'Albien-Cénomanien de Charente-Maritime (SO France)
Annales de Paléontologie, 2004Co-Authors: Bernard Gomez, Marc Philippe, Frédéric Thévenard, Véronique Daviero-gomez, Vincent Perrichot, Clément Coiffard, Didier NéraudeauAbstract:Resume Des plantes fossiles ont ete recemment collectees dans six localites de Charente-Maritime, d'âge Albien terminal a Cenomanien. Les restes foliaires, et en particulier l'etude des cuticules, etablissent une diversite plus elevee que ne le suggeraient les etudes paleoxylologiques precedentes. Les assemblages presentent des Pteridophytes (trois formes), des Coniferales ( Frenelopsis alata, Glenrosa nov. sp., Geinitzia , d'autres formes brachyphylles et pagiophylles, des cones mâles entiers et des ecailles ovuliferes isolees), des Ginkgoales ( Nehvizdya andegavense ), des Cycadales, de tres nombreuses feuilles d'Angiospermes (e.g., Myrtophyllum cf. angustum , cf. Pseudoasterophylites cretaceus ), et egalement quelques fleurs et des etamines isolees contenant des pollens in situ similaires a Clavatipollenites hughesii . Ces assemblages representent vraisemblablement une mosaique d'habitats distribues selon des gradients de salinite et d'exposition eoliennne.
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A new species of Nehvizdya (Ginkgoales) from the Lower Cretaceous of the Iberian Ranges (Spain).
Review of Palaeobotany and Palynology, 2000Co-Authors: Bernard Gomez, Georges Barale, Carles Martín-closas, Frédéric ThévenardAbstract:Abstract A new species of the formerly monospecific genus Nehvizdya Hlustik, Nehvizdya penalveri sp. nov. is described from the Albian of the Escucha Formation (Eastern Iberian Ranges, Teruel, Spain). The type species Nehvizdya obtusa Hlustik was first found in the Lower–Middle Cenomanian Peruc Member of the Peruc–Korycany Formation (Bohemian Massif, Czech Republic). Both taxa closely resemble each other, not only in leaf shape and venation pattern, but also in their epidermal structures and the occurrence of resin bodies. The Spanish species, however, is notable for its marked amphistomatic leaves with stomatal apparatus, which have inner folds inside the stomatal pits. Comparison with Eretmophyllum andegavense Pons et al. from the Cenomanian of the Baugeois Clays (Maine-et-Loire, France) allows us to transfer this species to the genus Nehvizdya Hlustik. The new combination proposed is Nehvizdya andegavense (Pons et al.) comb. nov. A taphonomic analysis in this layer appears to characterise a biocoenosis formed from N. penalveri sp. nov. and Frenelopsis alata (K. Feistmantel) Knoblock. Similar associations have been described in the Czech and French Cenomanian. In all three cases, the associations grew around coastal lagoons and ponds where they formed a shrubby halophyte vegetation.
Rafael Herbst - One of the best experts on this subject based on the ideXlab platform.
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Guavirá, una nueva localidad con maderas fósiles de la Formación Tacuary (Pérmico Superior) de Paraguay
Gaea - Journal of Geoscience, 2012Co-Authors: Valeria Leiva Verón, Rafael Herbst, Alexandra María Crisafulli, Víctor Filippi, Sonia MolinaAbstract:The article describes gymnospermous fossil woods from Guavira, a new locality exposing rocks from the Upper Permian Tacuary Formation in Paraguay. The identified taxa include the conifers Agathoxylon semibiseriatum (Pant & Singh) Leiva Veron & Crisafulli comb. nov. and Kaokoxylon rioclarense ex Mussa in Crisafulli & Leiva Veron (this paper), Polysolenoxylon whitei (Maniero) Krausel & Dolianiti, Chapmanoxylon jamuriense Pant & Singh, and Baieroxylon cicatricum , Prasad & Lele, a species frequently associated with the Ginkgoales. The discovery of this new assemblage has paleoenvironmental and paleobiogeographic significance because this is the first record of a species with a solenoid pith in the Permian of Paraguay. Thus, it allies the Tacuary Formation to other gondwanic sequences of South America and helps to establish comparisons between their xylotaphofloras. Keywords: wood anatomy, Upper Permian, Tacuary Formation, Paraguay.
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triassic Ginkgoales from northern chile
Andean Geology, 2010Co-Authors: Alejandro Troncoso, Rafael HerbstAbstract:En el marco de una revision de las tafofloras triasicas del norte de Chile, se presenta, en este articulo, el estudio de las hojas fosiles de Ginkgoales procedentes de dos yacimientos de la Formacion La Ternera y uno de la Formacion El Puquen. Se da cuenta de la presencia de 11 especies diferentes, una de ellas, Ginkgoites covacevicii sp. nov., la cual constituye una nueva especie para la ciencia. El conjunto muestra un marcado caracter gondwanico. Es notable que en los yacimientos de la Formacion La Ternera predominen especies (4) del genero Ginkgoites, en tanto en la Formacion El Puquen lo hacen las especies del genero Sphenobaiera (5). El conjunto estudiado sugiere una edad ladiniano-carnica y un paleoambiente lacustre marginal para los sedimentos portadores en la Formacion El Puquen, pero no son concluyentes, en cambio, salvo para indicar una edad triasica superior en la Formacion La Ternera.
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Gymnospermous woods (Coniferales, Taxales, and Ginkgoales) from the Upper Permian Tacuary Formation, Eastern Paraguay
Palaeobiodiversity and Palaeoenvironments, 2009Co-Authors: Alexandra Crisafulli, Rafael HerbstAbstract:Six gymnosperm woods from the Upper Permian Tacuary Formation from Eastern Paraguay are described. Protophyllocladoxylon dolianitii Mussa, has been recorded in the Lower Permian Rio Bonito Formation from Brazil and the Mount Glossopteris Formation of Antarctica; Podocarpoxylon paralatifolium Vozenin-Serra and Grant Mackie is similar to this species from the Lower Triassic Arawi Formation of New Zealand and the Upper Triassic Laguna Colorada Formation (El Tranquilo Group) from Santa Cruz province (Argentina); Austaloxylon teixeirae Marguerier has been recorded from the Raniganj Formation (India), the Karroo System (Mozambique), and the Yaguary Formation (Uruguay) all of Upper Permian age; Bageopitys herbstii Crisafulli, from the Yaguarí Formation of Uruguay; and Prototaxoxylon brasilianum Kräusel and Dolianiti, a wood assigned to the Taxales, has been recorded in the Upper Permian Estrada Nova Formation of Brazil. Wood with affinities to the order Ginkgoales is represented by Baieroxylon cicatricum Prasad and Lele recorded from the Triassic Tiki Formation from India and the Yaguarí Formation of Uruguay. All the woods show well-marked growth rings which reflect favorable climatic conditions. An analysis of the anatomical characters shows evolutionary intermediate stages between the more primitive (araucarioid) Paleozoic and the more advanced (mixed to abietoid) Mesozoic wood taxa. Except for the numerous species of Podocarpoxylon , Protophyllocladoxylon, Prototaxoxylon and Baieroxylon which have more extended biochrons, Australoxylon and Bageopitys are exclusive Upper Paleozoic (Permian) taxa.
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la flora triasica del grupo el tranquilo provincia de santa cruz patagonia parte vi Ginkgoales
Ameghiniana, 1999Co-Authors: Silvia Gnaedinger, Rafael HerbstAbstract:As part of the systematic study of the flora from El Tranquilo Group, the ginkgoal taxa are revised herein. The following species are considered: Ginkgoiies duioiiii Anderson and Anderson, Ginkgoites patmaia (Ratte) combo nov., Ginkgodium nathorsti Yokoyama, Ginkgodium sp.; Baiera africana Baldoni, Baiera gillkgoides Shirley; Sphenobaiera argentinae (Kurtz) Frenguelli, Sphenobaiera coronata Anderson and Anderson, Sphenobaiera stormbergensis (Seward) Frenguelli, S. sectina Anderson and Anderson, Sphenobaiera sp. d. s. browllialla Anderson and Anderson, Sphenobaiera sp. d. s. he/vetica Anderson and Anderson, Sphenobaiera sp. A, Sphenobaiera sp. B and Sphenobaiera sp. C from the Canadon Largo Formation and Ginkgoites waldeckensis (Anderson and Anderson) combo nov. and Ginkgoites sp. 1from the Laguna Colorada Formation.
Marc Philippe - One of the best experts on this subject based on the ideXlab platform.
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Le site à ambre et plantes du Cénomanien de Neau (Mayenne, France)
'EDP Sciences', 2020Co-Authors: Néraudeau Didier, Saint Martin Jean-paul, Saint-martin Simona, Jeanneau Laurent, Moreau Jean-david, Marc Philippe, Polette France, Gendry Damien, Brunet John, Tréguier JérômeAbstract:International audienceA new Cenomanian amber- and plant-bearing deposit has been discovered at Neau, in the Mayenne department (France). The Cenomanian fossiliferous lignites are located in karst filling in a substratum of Cambrian limestones. The amber corresponds mainly to tiny millimetric grains, devoid of arthropod inclusions, but rich in microorganisms, especially the sheated bacteria Leptotrichites resinatus, and containing pollen grains (Classopollis) and wood fibers (Araucariacae or Cheirolepidiaceae). The lignites provide abundant conifer and ginkgoale cuticle fragments (Frenelopsis, Eretmophyllum) and a lot of palynomorphs (e.g. Gleicheniidites senonicus, Cyathidites, Deltoidospora, Appendicisporites and Cicatricosisporites). The chemical signature of the amber suggests it was produced by conifers of the extinct family Cheirolepidiaceae. According to the palynological assemblage, the age of the lignites is upper lower Cenomanian or lower mid Cenomanian. The deposit environment corresponded to the upstream portion of a mangrove or the most inner part of a lagoon.Un nouveau site à ambre et plantes du Cénomanien a été découvert à Neau, en Mayenne (France). Les lignites fossilifères cénomaniens sont localisés dans des remplissages de karsts développés dans des calcaires du Cambrien. L’ambre se présente essentiellement sous forme de grains millimétriques, dépouvus d’inclusions d’arthropode, mais riches en microorganismes, notamment en bactéries gainées de type Leptotrichites resinatus, et contenant des grains de pollen (Classopollis) et des fibres de bois (Araucariacae ou Cheirolepidiaceae). Les lignites fournissent d’abondants fragments de cuticules de conifères et de Ginkgoales (Frenelopsis, Eretmophyllum) et une grande quantité de palynomorphes (e.g. Gleicheniidites senonicus, Cyathidites, Deltoidospora, Appendicisporites et Cicatricosisporites). La signature chimique de l’ambre suggère qu’il a été produit par des conifères de la famille éteinte des Cheirolépidiacées. D’après l’assemblage palynologique, l’âge des lignites est Cénomanien inférieur tardif ou Cénomanien moyen basal. L’environnement de dépôt correspondait à la partie amont d’une mangrove ou la partie la plus interne d’un lagon
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A reappraisal of Lignier's Mesozoic fossil wood collection: Ages, nomenclature and taxonomy
Review of Palaeobotany and Palynology, 2018Co-Authors: Marc Philippe, M. Rioult, J.-ph. Rioult, Frédéric ThévenardAbstract:Abstract In 1907 the French palaeobotanist Octave Lignier published a study of Jurassic fossil wood that was to become a seminal palaeoxylological work. Although the names he established were often used or recombined and his contribution is still often quoted today, the original material was never re-studied, except for one of the fifteen originally published samples. This material was only recently been rediscovered, after it was thought to be lost since the 1980s. Here we make use of this opportunity to re-evaluate stratigraphical attributions and ages of Lignier's original samples, to review their nomenclatural status and discuss their taxonomical assignment. Three new combinations are introduced: ( Agathoxylon tranchantii (Lignier) comb. nov., Baieroxylon divesence (Lignier ex Seward) comb. nov., Brachyoxylon blevillense (Lignier) comb. nov.), and a new species ( Agathoxylon crasseradiatum sp. nov.) is published based on Lignier's material. Baieroxylon divesence is anatomically closely related to modern ginkgo and hence an interesting milestone is the little documented history of Ginkgoales wood.
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A Jurassic wood providing insights into the earliest step in Ginkgo wood evolution
Scientific Reports, 2016Co-Authors: Zikun Jiang, Marc Philippe, Yongdong Wang, Wu Zhang, Ning Tian, Shaolin ZhengAbstract:The fossil record of Ginkgo leaf and reproductive organs has been well dated to the Mid-Jurassic (170 Myr). However, the fossil wood record that can safely be assigned to Ginkgoales has not yet been reported from strata predating the late Early Cretaceous (ca. 100 Myr). Here, we report a new fossil wood from the Mid-Late Jurassic transition deposit (153–165 Myr) of northeastern China. The new fossil wood specimen displays several Ginkgo features, including inflated axial parenchyma and intrusive tracheid tips. Because it is only slightly younger than the oldest recorded Ginkgo reproductive organs (the Yima Formation, 170 Myr), this fossil wood very probably represents the oldest bona fide fossil Ginkgo wood and the missing ancestral form of Ginkgo wood evolution.
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new species of coniferales and Ginkgoales from the lias of la ligua chile with an evaluation of paleoxylological record in the jurassic of south america
Andean Geology, 2010Co-Authors: Teresa Torres, Marc PhilippeAbstract:Se estudiaron maderas fosiles de edad sinemuriana, provenientes de estratos de la Formacion Quebrada del Pobre, que afloran al noreste de la ciudad de La Ligua (71°13'W; 32°24'S), V Region, Chile. El analisis xilotomico permitio distinguir dos nuevas morfoespecies: Agathoxylon liguaensis sp. nov. y Baieroxylon chilense sp. nov. El registro, en este trabajo, de Baieroxylon, perteneciente a las Ginkgoales, amplia a seis el numero de morfogeneros reconocidos en el Jurasico de Sudamerica. El ancho de los anillos anuales de los taxones estudiados indica que los arboles crecieron en condiciones ambientales muy favorables, en un paleoclima calido con bajas fluctuaciones de temperatura.
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Assemblages floristiques de l'Albien-Cénomanien de Charente-Maritime (SO France)
Annales de Paléontologie, 2004Co-Authors: Bernard Gomez, Marc Philippe, Frédéric Thévenard, Véronique Daviero-gomez, Vincent Perrichot, Clément Coiffard, Didier NéraudeauAbstract:Resume Des plantes fossiles ont ete recemment collectees dans six localites de Charente-Maritime, d'âge Albien terminal a Cenomanien. Les restes foliaires, et en particulier l'etude des cuticules, etablissent une diversite plus elevee que ne le suggeraient les etudes paleoxylologiques precedentes. Les assemblages presentent des Pteridophytes (trois formes), des Coniferales ( Frenelopsis alata, Glenrosa nov. sp., Geinitzia , d'autres formes brachyphylles et pagiophylles, des cones mâles entiers et des ecailles ovuliferes isolees), des Ginkgoales ( Nehvizdya andegavense ), des Cycadales, de tres nombreuses feuilles d'Angiospermes (e.g., Myrtophyllum cf. angustum , cf. Pseudoasterophylites cretaceus ), et egalement quelques fleurs et des etamines isolees contenant des pollens in situ similaires a Clavatipollenites hughesii . Ces assemblages representent vraisemblablement une mosaique d'habitats distribues selon des gradients de salinite et d'exposition eoliennne.