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Dilambodont Molars :a functional interpretation of their evolution
Percy M. Butler
Keywords: Convergent evolution; Dilambdodont; Molar function; Molar teeth
 
  Abstract

    In dilambdodont molars the primitive crest between paracone and metacone (centrocrista) is represented by a pair of crests that join the mesostyle (postparacrista, premetacrista). The cutting action of these crests against the crests of the hypoconid is described. Dilambdodonty is a derived adaptation for greater cutting efficiency. It has evolved several times and in more than one way. 


  Article infos

Published in Vol. 25, Fasc. 2-4 (1996)

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Angolabatis nom. nov.,a replacement name for the Cretaceous genus Angolaia Antunes & Cappetta, 2002 (Chondrichthyes: Rajiformes), a preoccupied name.
Miguel T. Antunes and Henri Cappetta
Keywords: Angola; Campanian/Maastrichtian; homonymy; Hypsobatidae; nomen novum; Rajiformes
 
  Abstract

    In 2002, Antunes & Cappetta published several new taxa (genera and species) in a paper on Cretaceous elasmobranch faunas from Angola. One of the new genera was named Angolaia (Rajiformes, Hypsobatidae; type-species: Angolaia benguelaensis Antunes & Cappetta, 2002, Late Campanian/Early Maastrichtian of Angola). Recently, Dr. Christian Kammerer kindly informed us that the genus Angolaia was preoccupied by a cicadellid homoptere (Insecta), published by Linnavuori & Al-Ne'amy, 1983. So, according to mIes of the International Code of Zoological Nomenclature (ICZN 1999, articles 52, 60) this name became unavailable. Consequently, the Rajiformes genus Angolaia is a junior homonym, invalid and must be rejected. In replacement, we propose the new name Angolabatis


  Article infos

Published in Vol. 34, Fasc. 1-2 (2006)

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Le genre Plagiolophus (Palaeotheriidae, Perissodactyla, Mammalia): révision systématique, morphologie et histologie dentaires, anatomie crânienne, essai d'interprétation fonctionnelle
Jean-Albert Remy
Keywords: New taxa; Paléogène; perissodactyls; skull anatomy; tooth histology
 
  Abstract

    The genus Plagiolophus is documented, almost solely in Western Europe, from the middle Eocene up to the mid Oligocene (MP 12 to MP 25), i.e. more than for 15 MY. Seventeen species are now recorded whose two of them are new, P. ringeadei nov. sp. and P. mamertensis nov. sp. Some anatomical variations and the deflection of certain evolutionary trends justify the distinction of three subgenera, Paloplotherium, Fraasiolophus nov. and Plagiolophus s.s. The genus displays a wide range in size and weight (between 10 and 150 kg). The detailed description of the skull of several species is here given for the first time.
    Despite important evolutionary drifts during this long time span, the dentition shows a great structural homogeneity, which renders difficult the determination of fragmentary specimens or isolated teeth. It is characterized by a great heterodonty; premolars are little molarized and present a certain regression through time with paradoxically some progress in the molarization. The hypsodonty increases: the first Plagiolophus are hardly less brachyodont than Propalaeotherium, and the last ones are nearly as hypsodont as Merychippus from the early Miocene. The upper molars change from a wide crown pattern, with an open occlusal surface, lightly oblique transverse lophs and rounded internal cusps, to a narrower pattern, with a frontally constricted occlusal surface and internal lophs aligned parallel to the ectoloph. The M3/3 become always longer.

    The dental enamel displays horizontal Schreger-bands with imprecise limits occupying only the middle part of the enamel layer. The dentine is remarkable by its high rate of pericanalicular dentine. The crown cementum, lacking in earlier forms, increases to the point where it fills the occlusal valleys of the
    teeth.

    The masticatory musculature shows a increasing prominence of the temporal, with probably an important role devoted to the pterygoid muscles in lateral movements related to a two-phase type of chewing.

    The evolution of the dentition, of the masticatory musculature and of the repartition of masticatory forces indicate that the Plagiolophus have known different diets through their long evolutionary history; at first browsers they became mixed feeders and finally grazers. Their relatively long neck allowed these animals to reach different vegetal layers. The strength of the nuchal crests also suggests that they were able to have strong backwards movements of the head to pull up their food.

    This evolution of diet seems related to the slow degradation of environmental conditions attested during this period in western Europe, with the generalization of more open landscapes, increasing aridity and more marked seasons.

    Besides, a remodeling of the face is ontogenetically and along time observed, in relation with the evolution of the masticatory apparatus and especially with that of the mandibular lever arm. The postcanine diastemata become longer in the course of evolution; the free extremities of the nasals are always relatively long which contradicts the hypothesis according to which Paloplotherium may have had a trunk. At last the lineage Fraasiolophus can be distinguished by the presence of a deep malar fossa, probably related to a strong development of the maxillo-labialis superior muscle.

    The orbit is always large and tends to increase in size, which indicates a good development of the vision and its increasing role in the life relations. A peculiar type of epitympanic sinus could have been used as a resonance chamber insuring a certain amplification of sounds before their transmission to the eardrum. The endocranial cast reveals a relatively large brain with an advanced degree of gyrencephaly. Beside the role eventually played in food research and social relations, these neurophysiological abilities, also related to an advance in cursorial fitness, could have contributed to the survival of these animals facing the predation pressure of the first fissipede carnivores and the competition with new immigrant herbivores after the "Grande Coupure".
    On the basis of some shared apomorphies with the Pachynolophinae, which prevent from considering the latter as Equidae (molarization of the premolars, reduction of the premaxilla dorsal apophysis, peculiar epitympanic sinus, splitting of the jugular process), the hypothesis of an autochthonous origin of Plagiolophus issued from a form near Propalaeotherium, is once again proposed and discussed. Finally, intra-generic relationships are taken into consideration. 


  Article infos

Published in Vol. 33, Fasc. 1-4 (2004)

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La palichnofaune de vertébrés tétrapodes du permien supérieur du Bassin de Lodève (Languedoc-France).
Georges Gand, Jacques Garric, Georges Demathieu and Paul Ellenberger
Keywords: Footprints; France; Languedoc; Lodève basin; new ichnotypus; Saxonian; Upper Permian
 
  Abstract

    Near "la Lieude", in the Lodève basin, more than a thousand of footprints are distributed in a twenty of trackways which amounts to 220 m length. They have been found on calcareous siltstone level in the B site named also "Réserve Naturelle Volontaire". This last is located in the Saxonian summit dated Upper Permian. "La Lieude" tracks are described by using statistical methods then they are compared with others from the world Permian. What allows to distinguish 4 following ichnotaxa: Lunaepes ollierorum nov.ichnosp., Merifontichnus thalerius nov. ichnogen. and nov. ichnosp., Planipes brachydactylus nov.ichnosp. and Brontopus circagiganteus nov. ichnosp. All these traces are attributed with possibility or probability to Therapsida or to Therosauria, except Brontopus circagiganteus nov. ichnosp. that could be due to Caseamorpha. All these animals whose sizes have been estimated between l and 5 m lived probably in a playa environment.The biological and sedimentological data from "la Lieude" footprints levels compared with informations provided by the tracks orientations, suggest the following scenario. Animals coming from the North have crossed a sandy channel bank with plants zones by directing to the South for the majority. Maybe, they were going to the lacustrine part of the playa, close to "la Lieude" footprints that they have just trampled on. 


  Article infos

Published in Vol. 29, Fasc. 1 (2000)

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Les Pseudosciuridae (Mammalia, Rodentia) de l'Eocène moyen de Bouxwiller, Egerkingen et Lissieu.
Jean-Louis Hartenberger
Keywords: Bouxwiller; cranium; Egerkingen; Middle Eocene; Rodents

doi: 10.18563/pv.3.2.27-64
 
  Abstract

    The description of new material from three classic middle Eocene localities of western Europe permits the addition of details to the systematics of primitive Pseudosciurids. The cranial anatomy of Protadelomys cartieri (STEHLIN and SCHAUB) from Egerkingen is described here and compared to that of the Adelomyines from the late Eocene, until now the only ones known. The morphologic and biometric study of the dentition of P. cartieri compared to that of P. alsaticus n. sp. from Bouxwiller and P. Iugdunensis n. sp. from Lissieu, forms respectively older and younger than P. cartieri, permits the evolutionary tendencies of the group to be demonstrated and shows that notable differences in age exist between these localities. This ensemble of forms can constitute a valuable guide lineage in the establishment of a fine stratigraphy of the period. Other less well known lineages are present at Egerkingen along with P. cartieri. They can be related to genera that have been noted int he late Eocene. In conclusion, a criticism of recent zonation proposals, made by divers authors, completes this article. 


  Article infos

Published in Vol. 03, Fasc. 2 (1969)

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The microfauna of the Djebel Qafze Cave
G. Haas
Keywords: Micromammals; Rodents
 
  Abstract

    Abstract not available 


  Article infos

Published in Vol. 05, Fasc. 5 (1972)

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Designating a lectotype for Mesacanthus pusillus (Gnathostomata: Acanthodii)
Matthew Baron and Kevin Seymour
Keywords: acanthodians; Chordata; Devonian; Midland Valley; Orcadian Basin

doi: 10.18563/pv.44.1.e2
 
  Abstract

    The early gnathostome genus Mesacanthus is well represented in both Lower Old Red Sandstone and Middle Old Red Sandstone assemblages of northern and central Scotland. This ‘acanthodian’ taxon is currently thought to comprise two valid species: M. mitchelli and M. pusillus. Although the whereabouts of the holotype of M. mitchelli (NHMUK PV P560) is known, the syntype material for M. pusillus has long been thought lost. Here we identify at least one specimen that formed part of the original syntype material for M. pusillus, albeit in a slightly different condition than when it was originally figured. This specimen is ROM 25872, which is here designated as the lectotype. A second specimen – ELGNM 1978.191.1 – could represent another of the syntype specimens, but poor preservation quality makes it impossible to be certain. 


  Article infos

Published in 44-1 (2021)

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S.I. Data
Saturnin Garimond (1914-1987)
Jean-Albert Remy
Keywords: biography
 
  Abstract

    Biographie et liste des publications de S. Garimond. 


  Article infos

Published in Vol. 17, Fasc. 3 (1987)

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Les traces de pas d'amphibiens, de dinosaures et autres reptiles du Mesozoïque Français : inventaire et interprétations.
Georges Gand, Georges Demathieu and Christian Montenat
Keywords: Footprints; France; Inventory; Mesozoic; palaeontology; palaeovenvironments; Stratigraphy

doi: 10.18563/pv.35.1-4.1-149
 
  Abstract

    Since the 19th century, thousands of footprints were observed in the geological series of the French Mesozoic. All are located in the Triassic and Jurassic. After a promising beginning, in France, it is only a few papers which will be published in the first half 20th century, unlike the USA and of others countries of Western Europe. One ought to wait about 1950 for a revival and now they are nearly 200 papers which were devoted to the ichnofossils. The literature abundance and the renewed interest of the naturalists for the palichnologic studies decided to us to write a synthesis work. This one begins with a stratigraphic inventory in which, localisation, age and paleontological contents of about 180 fossiliferous sites are specified. After having pointed out the followed methods, the footprints paleontological interpretation is then approached in detail and the results obtained are replaced in stratigraphy to deduce the fauna evolution during the Mesozoic. So, it appears that Ichnologic data, more varied and rich in the Triassic and Liassic than those relating to the bones, very rare for the considered periods, are very informative. The middle Triassic (Anisian-Ladinian), thus reveals Cotylosauria, Lepidosauria, Crurotarsi with Rauisuchia, Ornithosuchidae, Crocodylia and Dinosauromorpha more the "Prodinosauria": Dinosamiforme whose skeletons are known in Argentina but only in Ladinian. The rather fast domination of Dinosaurs during Norian is also as well shown. The almost exclusive presence of their footprints, up to fifty cm long, in the Lower Hettangian indicates their supremacy in the environments. Footprints characterise not very deep life places located between inter-supratidal limits and often out of water. Sedimentologic and Palaeontologic studies showed that they were great coastal spaces during Middle Triassic, flood-plain with sebkhas while Upper Triassic, and a large !!coastal marsh!! in Grands-Causses during Liassic in which, mainly, fine stromatolithic layers were deposited. During the same periad, bay beaches spread in Vendée. During the Middle Jurassic, they are also brackish to lacustrine environments and recifallagoons in- the Upper Jurassic. Numerous measurements of the footprints and trackways directions showed that the animaIs moved there in weil defined directions, for long periods. They seem due to the palaeotopography of the life environments relatively stable. Also, the discovery of vegetal radicular networks and small footprints far away from the continental borderlands has suggested that the animals continuously lived in these palaeoenvironnements, belonging to large ecosystems, where the sedimentation rate was weak. This explains that thebadies could not fossilize there but only their footprints through the cyanobacterian action in main cases. From the vertical distribution of different ichnospecies, defined with adapted statistical methods, explained in this work, a palichnostratigraphy was established for the Middle Triassic. Although the footprints are also abundant in Hettango-Sinemurian of "Grands-Causses" and the Vendée, it was not possible, up to now, to establish any zonation in this series; Probably because the palichnofauna is too little diversified there, currently reduced to a majority of Theropods II-IV tridactyl traces.
      


  Article infos

Published in Vol. 35, Fasc. 1-4 (2007)

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Les mammifères Montiens de Hainin (Paléocène moyen de Belgique) Part III : Marsupiaux
Jean-Yves Crochet and Bernard Sigé
Keywords: Belgium; Marsupials; Paleobiogeography; Paleocene
 
  Abstract

    The oldest european marsupials are described from some specimens (isolated upper molars) recently found from the Hainin sediment (Middle Paleocene of Belgium). These fossils document a new species of the Peradectes genus. They give evidence of a much older occurrence of the marsupials in Europe than it was assumed. They allow us to postulate a didelphid dispersal from South America towards the western-holarctic area operating in two phases : the first one of the Peradectes genus at the end of the Cretaceous; the second one of the Didelphíni tribe at the end of the Paleocene. A central american crossing is likely for the first one,  whereas a transafrican way is tentatively argued for the second one. 


  Article infos

Published in Vol. 13, Fasc. 3 (1983)

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Table ronde sur les phosphorites du Quercy Montauban 15-16 Décembre 1972
Louis Thaler and Jean-Louis Hartenberger
Keywords: Quercy Phosphorites
 
  Abstract

    Voici une centaine d'années débutait sur les Causses du Quercy l'exploitation des phosphorites qui devait permettre d'amasser des collections de Vertébrés fossiles uniques au monde. Ces fossiles firent l'objet de nombreuses publications et les noms de Filhol, Gaudry, Schlosser, Stehlin, Teilhard de Chardin sont attachés à ces premières études.

    Après quelques années de prospection, les fouilles dans le Quercy ont repris en 1965, organisées par les laboratoires montpelliérains et parisiens. Ces premières recherches ont été aidées par le Centre National de la Recherche Scientifique qui a organisé une « table ronde» pour faire le point des premiers résultats obtenus. Ceux-ci ont été jugés suffisamment prometteurs pour que le C.N.R.S, ait décidé de poursuivre son effort par l'intermédiaire d'une Recherche Coopérative sur Programme.



      


  Article infos

Published in Vol. 06, Fasc. 1-2 (1974)

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Experimental taphonomy inavian eggs and eggshells: effects on early diagenesis.
Ana M. Bravo, D. A. Buscalioni, Lauro Merino and B. G. Müller
Keywords: archosaurian eggshells; avian egg; Experimental taphonomy; geochemical analysis; pyritisation; Upper Cretaceous
 
  Abstract

    We experimentally explore the early taphonomic stages involving the decay and biodegradation of buried eggs and eggshells. Unfertilised commercial chicken eggs and eggshell fragments were buried in plastic containers and were kept under controlled conditions for eight months. Half of the containers were filled with marl, and the remainder with sand. All were saturated with fresh tap water, acidified water, sulphate water, or seawater. They were kept in the dark at 23.4-26 °C, except one, which was kept in a heating chamber at 37.4°C. We expected that different burial conditions would produce distinct taphonomic outcomes. Instead, the taphonomic alterations of buried eggs parallel that of the alteration of egg proteins (i.e., denaturation and/or putrefaction) with an additional role played by the eggshell. Mummification, encrustation, distortion and fragmentation, and necrokynesis (vertical displacement) depend on organic matter decay. The experiment identifies environmental conditions that may favour or actively promote these taphonomic processes. Of these, early pyritization is one of the most relevant. For comparative purposes, samples of fossil and extinct eggshell representing three distinct environmental burial conditions were examined. These included Megaloolithus, Caiman crocodilus, and Struthio camelus ootypes. The geochemical analysis of these eggshells showed no significant differences among the chemical variables of these fossil and extant ootypes. Eggshells exhibited a stable composition over a range of experimental conditions. 
      


  Article infos

Published in Vol. 32, Fasc. 2-4 (2003)

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Contributions à l'étude du gisement Miocène supérieur de Montredon (Hérault). Les grands mammifères. 3 - Les artiodactyles ruminants
Léonard Ginsburg and Herbert Thomas
Keywords: Artiodactyla; France; Montredon; Ruminentia; Upper Miocene
 
  Abstract

    The remains of Ruminantia are very rare at Montredon. No specific determination was possible. We have only one Micromeryx, one small cervid, one tragocere and one (?) gazella. The faunal spectrum is in good correlation with the general retreat of the cervids in the European upper Miocene, but in contrast it is not convenient for the bovids, which are in expansion at the same time. For them, we have to invoke the local ecological conditions.
      


  Article infos

Published in Vol. 18, Ext (1988)

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Premières données sur les rongeurs de la formation de Ch'orora (Ethiopie) d'âge Miocène supérieur. I: Thryonomyidés
Jean-Jacques Jaeger, Jacques Michaux and Maurice Sabatier
Keywords: Ethiopia; Paraulacodus; Rodents; Upper Miocene
 
  Abstract

    The genus Paraulacodus has been collected in the Ch'orora formation of Upper Miocene age, in Ethiopia. The new species, P. johanesi n. sp.. is more evolved than the previously described indian species P. indicus HINTON of the Siwalik Hills area. The morphological gap between P. johanesi and the present Thryonomys is still important. 


  Article infos

Published in Vol. 9, Ext (1980)

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Acinoptèrygiens du Stéphanien de Montceau-les-Mines (Saône-et-Loire, France).
Daniel Heyler and Cécile Poplin
Keywords: Aeduelliforms; Biogeography; Palaeonisciforms; paramblypteriforms; Stephanien
 
  Abstract

    The study of new specimens from the Stephanian shales of Montceau-les-Mines confirms and enlarges the number of groups already known in this area. Among the Palaeonisciforms, “form A" is now known more completely, although no diagnosis or name can yet be given for it. “Form B" is redescribed and its relationships with “Elonichthys robisoni" are discussed. A palaeoniscid is recorded which resembles those from Bourbon l'Archambault. The paramblypteriforms occur rather frequently, but no genera can be determined. The aeduelliforms comprise some specimens close to Aeduella blainvíllei from Muse (Autun basin), and a new genus. Comparison of the latter with two fossils from Lally allows creation of two new species and a new family. This diversification of the aeduelliforms during this middle Stephanian leads to the hypothesis that the group originated at least as early the lower Stephanian. This material prooves again the characteristic endemism of this fauna, particularly of the aeduelliforms which are known only in the Massif Central where they diversified during the Permo-Carboniferous. Biogeographical consequences are discussed. 


  Article infos

Published in Vol. 13, Fasc. 3 (1983)

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Cricetid and arvicolid rodents of the California wash local fauna, late Blancan of the san Pedro Valley, Arizona.
Cristiana Mezzabotta
Keywords: Arvicolidae; Blancan; Cenozoic; Cricetidae; Mammals
 
  Abstract

    An assemblage of micromammals is reported from California Wash, a fossil bearing continental deposit in the San Pedro Valley, Arizona, late Blancan in age. Cricetid and Arvicolid rodents are richly represented, including four and two species, respectively. This study mainly focuses on Sígmodon, the most abundant form. The sample of Sigmodon is compared to samples of the same genus from other localities of the San Pedro Valley of comparable age, and some inferences on the taxonomy of the genus are attempted. The specimens are referred to Sigmodon minor and Sigmodon cf. S. curtisi. Other cricetids (Onychomys pedroensis and Baiomys brachygnathus) and arvicolids (Mictomys vetus and Ondatra ídahoensis) are also recognized and described. 


  Article infos

Published in Vol. 26, Fasc. 1-4 (1997)

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A late Eocene palaeoamasiine embrithopod (Mammalia, Afrotheria) from the Adriatic realm (Island of Rab, Croatia)
Fabrice Lihoreau, Ljerka Marjanac, Tihomir Marjanac, Ozan Erdal and Pierre-Olivier Antoine
Keywords: Balkanatolia; Grande Coupure; Great Adria; Paleobiogeography; Systematics

doi: 10.18563/pv.47.1.e1
 
  Abstract

    A cheek tooth recently unearthed in the Lopar Sandstone unit, of late Eocene age, in the northern part of Rab Island, Croatia, is one of the very few Eocene mammalian remains found in the Adriatic area. Thorough comparison of this tooth with those of Old-World Palaeogene mammalian orders suggests that it is a M3 belonging to an embrithopod afrothere. The specimen is referred to as Palaeoamasia sp. This genus was formerly known only in Eocene deposits of Anatolia but with close relatives in Romania among Palaeoamasiinae. The geographical distribution of this subfamily perfectly matches the recently-named Balkanatolian landmass, which experienced in-situ evolution of endemic mammals prior to the Grande Coupure event that occurred around the Eocene–Oligocene transition. This last event is characterised by massive Asian immigration in Western Europe and the supposed extinction of many endemic Central and Western European mammals, including Palaeoamasiinae.
      


  Article infos

Published in 47-1 (2024)

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First evidence of an early Miocene marine teleostean fish fauna (otoliths) from la Paillade.(Montpellier,France)
Bettina Reichenbacher and Henri Cappetta
Keywords: Aquitanian; Biostratigraphy; La Paillade; marine deposits; Miocene; otoliths; Palaeoecology; Palaeogeography; Southern France; Teleostei
 
  Abstract

    A fossil fish fauna, based on 5533 otoliths, from the La Paillade locality at Montpellier is described and figured. The otolith-bearing marls correlate to mammal zone MN l (Aguilar, 1982), and thus represent the earliest Miocene. The fish fauna consists of 30 taxa belonging to 20 families. Two species are new: Dussumieria sittigi and Liza gaudanti. The predominant faunal element is the Lesueurigobius vicínalis-species complex, composing 73% of all investigated otoliths. The palaeoecological analysis reveals a marine to euryhaline fish fauna living under tropical to subtropical conditions in the transition zone littoral - sublittoral. Water depth probably was more than 10 m. The scarcity of pelagic físhes suggests that the habitat was either a sheltered bay and/or far away from the open sea. Furthermore, some genera represented in the La Paillade fish fauna presently live exclusively in the Indopacific realm. Their presence strongly supports a broad connection between the Indian Ocean, the Mediterranean, and the Paratethys Seas during the Early Miocene (Aquitanian). From a palaeobiogeographical point of view, faunal relationships were found between the La Paillade fish fauna and both the Paratethys fish fauna and the fish fauna from the deposits in the Upper Rhinegraben and the Mayence and Hanau Basins (Germany).



      


  Article infos

Published in Vol. 28, Fasc. 1 (1999)

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Première occurrence d'un mégachiroptère ptéropodidé dans le Miocène moyen d'Europe (Gisement de Lo Fournas-II, Pyrénées-Orientales, France).
Jean-Pierre Aguilar, Marc Calvet, Jean-Yves Crochet, Serge Legendre, Jacques Michaux and Bernard Sigé
Keywords: Europe; First occurence; Megachiroptera; Middle Miocene; Teeth
 
  Abstract

    A lot of isolated teeth of a pteropodid fruit bat has been recently found within an assemblage of micromammals recovered from a karstic fissure filling named Lo Fournas-Il near the locality of Baixas (Pyrénées-Orientales, France). The fauna is Middle Miocene Serravallian age. The fossil fruit bat appears morphologically close to Rousettus; its size is that of a recent medium-sized fruit bat. While the fruit bats are very poorly known as fossils, this discovery shows that one of their recent types of dentitions was perfectly established by Middle Miocene times, and supports the presumed long geologic story of the suborder. One of the major invasions of the Old World fruit bats, supposed originated from SE Asia, reached up to Europe. A suborder unit is added to the miocene fauna of this continent. 


  Article infos

Published in Vol. 16, Fasc. 3 (1986)

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Essai de reconstitution d'un paysage du Quercy vers -35 Ma. (Esquisse de Christian Pondeville, 1977).
Monique Vianey-Liaud and Christian Pondeville
Keywords: Landscape reconstruction; Quercy Phosphorites
 
  Abstract

    Le Quercy est aujourd'hui un vaste plateau calcaire, parcouru par un réseau karstique actif, pro· fondément entaillé par des vallées aux falaises abruptes, comme celles du Lot ou du Célé. Sur un sol peu épais domine la forêt de chênes, accompagnés de cornouillers, érables, genévriers. La faune est pauvre, peu diverse, et les nombreux chasseurs se satisfont de gibier d'élevage ...
    Il y a trente-cinq millions d'années environ, le paysage était bien différent. La période de l'Eocène supérieur, qui s'achevait, avait été chaude et humide, si l'on se réfère à la fois aux paléotempératures (calculées à partir de sédiments marins extra-européens) et aux restes fossilisés de végétaux typiquement tropicaux.
    Le Causse du Quercy devait être un plateau très disséqué par la karstification, à surface lapiazée creusée de gouffres en rapide évolution interne, et couvert d'un sol assez épais. Une forêt tropicale humide, avec notamment des Myricacées et des gymnospermes, recouvrait l'ensemble du pays, à peine interrompue au niveau des rares points d'eaux situés dans les bas-fonds. Dans ce cadre vivait une faune considérablement différente de la maigre faune actuelle. Si nous pouvons l'imaginer, c'est grâce aux cadavres des animaux entraînés dans les cavités par les eaux courantes ou les prédateurs, ou bien logeant et mourant dans les milieux souterrains. Nombre de ces restes, fossilisés, sont parvenus jusqu'à nous et sont aujourd'hui l'objet d'étude. 


  View editorial

Published in Vol. 08, Fasc. 2-4 (1978)

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