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Page 9 of 19, showing 20 record(s) out of 366 total

Mammals and stratigraphy : the Paleocene of Europe
Donald E. Russell, Jean-Louis Hartenberger, Charles Pomerol, Sevket Sen Logo, Norbert Schmidt-Kittler and Monique Vianey-Liaud Logo
Published online: 01/12/1982

Keywords: Europe; Mammalia; Mammalian biochronology; Paléogène; Stratigraphy

https://doi.org/10.18563/pv.12.ext

  Abstract

    The mammalian faunas of the Paleogene of Europe and their localities are reviewed with comments on problems of European stratigraphy (epoch, stage and substage limits) and on the possibilities of faunal migrations. Radiometric dating is discussed. A stratigraphic scale for the Paleogene is presented, as well as a refined system of sequential faunal levels. 


  PV article infos

Published in Vol. 12, Ext (1982)

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Les poissons crétacés et tertiaires du bassin des Iullemmeden (République du Niger)
Henri Cappetta Logo
Published online: 15/09/1972

Keywords: Actinopterygians; Cenozoic; Cretaceous; Dipnoans; Selachians

https://doi.org/10.18563/pv.5.5.179-251

  Abstract

    The present work is devoted to the study of the Cretaceous and Tertiary fishes (teeth of Selachians, Actinopterygians and Dipnoans) collected during a recent expedition in Niger. The Maestrichtian localities have yielded a new genus and a new subspecies of Selachian: Igdabatis sigmodon nov. gen., nov. sp. and Lamna biauriculata nigeriana nov. subsp. The locality of Sessao, which has been attributed to the Thanetian by means of the study of the fish, has furnished by screen-washing an interesting fauna wherein six new species are described: Raja Iouisi, Dasyatis sessaoensis, D. sudrei, D. russelli, Hypolophites thaleri and Ceratodus casieri. Comparison of these faunas with contemporary faunas of Africa has brought out a certain endemism in the Iullemmeden Basin during the late Cretaceous and the early Tertiary. 


  PV article infos

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

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Les insectivores des phosphorites du Quercy
Jean-Yves Crochet
Published online: 15/11/1974

Keywords: Insectivores; Quercy Phosphorites

https://doi.org/10.18563/pv.6.1-2.109-159

  Abstract

    Many types of insectivores have been described from specimens found in the Quercy phosphorites. These remains very often were not dated because they came from old collections. Recent excavations have permitted the situation of Amphidozotherium cayluxi FILHOL in the late Eocene. Two new genera are descrlbed based on material both from the old collections (Cryplotopos nov. g.) and from that recently recovered (Darbonetus nov. g., beginning of the middle Oligocene). Their systematic positions are revised and comparisons with American faunas are made. Amphidozotherium is not a talpid, but an erinaceoid belonging to an indeterminate family. Saturninia gracilis STHELIN is classified among the Nyctitheriinae, Myxomygale antiqua FILHOL among the Urotrichini Talpinae, and the genus Geotypus POMEL among the Scaptonichini Talpinae. A new study of the talpids from Auvergne has been rendered necessary. During the late Eocene and Oligocene precise morphology relationships existed between certain insectivores of Europe and North America. 


  PV article infos

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

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Les gangas (Aves, Columbiformes, Pteroclidae) du Paléocène et du Miocène inférieur de France.
Cécile Mourer-Chauviré Logo
Published online: 11/02/1993

Keywords: Birds; evolution; Lower Miocene; New taxa; Oligocene; Paleoecology; Paulhiac; Quercy Phosphorites; Saint-Gérand-Ie-Puy; Sandgrouse; Upper Eocene

https://doi.org/10.18563/pv.22.2-3.73-98

  Abstract

    The two species of Sandgrouse from Quercy, Pterocles validus MILNE-EDWARDS and P. larvatus MILNE-EDWARDS, are ascribed to the genus Archaeoganga MOURER-CHAUVIRÉ which includes a third, very large species, A. pinguis. The Sandgrouse of Saint-Gérand-le-Puy, Pterocles sepultus MILNE-EDWARDS, is ascribed to a new genus, Leptoganga. This form appears in the Upper Oligocene of Quercy, in Pech Desse and Pech du Fraysse localities, and is still present in the Lower Miocene of Saint-Gérand-le-Puy and Paulhiac. Recent Sandgrouse live in semidesert or desert areas. The indications provided by mammal and bird faunas in the localities where sandgrouse were found, confirm that the paleoenvironment was open and arid. The morphological study of these fossils indicates that, in the Upper Eocene, the Pteroclidae were already completely individualized with respect to Charadriiformes. 


  PV article infos

Published in Vol. 22, Fasc. 2-3 (1993)

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Pseudorhyncocyon cayluxi Filhol, 1892 insectivore géant des phosphorites du Quercy
Bernard Sigé
Published online: 15/11/1974

Keywords: Insectivores; Leptictidae; Quercy Phosphorites

https://doi.org/10.18563/pv.6.1-2.33-46

  Abstract

    Une hémimandibule et une molaire supérieure recueillies dans le gisement oligocène inférieur d'Escamps (phosphorites du Quercy) fournissent de nouvelles informations sur le genre Pseudorhyncocyon FllHOL, grand insectivore longirostre du Paléogène d'Europe, fossile très mal connu jusqu'ici. Des comparaisons avec les macroscélididés africains, géolabididés nord-américains, et leptictidés euraméricains permettent de rattacher cet amimal aux leptictidés, et de le rapprocher du genre Lepticidium TOBIEN, au sein de la sous-famille européenne nouvelle des pseudorhyncocyoninés. 


  PV article infos

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

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Le genre Mesembriacerus (Bovidae, Artiodactyla, Mammalia) : un Oviboviné primitif du Vallésien (Miocène supérieur) de Macédoine (Grèce)
Geneviève Bouvrain and Louis de Bonis Logo
Published online: 15/12/1984

Keywords: Bovidae; Cladistics; Late Miocene; Ovibovinae; Vallesian

https://doi.org/10.18563/pv.14.4.201-223

  Abstract

    The bovid Mesembriacerus melentisi, the numerous skulls, teeth and limb bones of which are described from the locality Ravin de la Pluie (Macedonia, Greece), bears some features which allow us to put it in the tribe ovibovini (Ovibovinae) with several other Miocene genera and the Recent one Ovibos. A cladogram gives the phyletic relationships within this tribe. It shows that Mesembriacerus which is one of the oldest genera, is also the most primitive. The limb bones are as elongated as those of Recent cursorial bovids and they show, as does the bulk of the fauna, an open environment for the locality. 


  PV article infos

Published in Vol. 14, Fasc. 4 (1984)

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Deux nouveaux primates dans l'Oligocène inférieur de Taqah (Sultanat d'Oman): premiers Adapiformes (?Anchomomyini) de la péninsule arabique?
Emmanuel Gheerbrant Logo, Herbert Thomas, Jack . Roger, Sevket Sen Logo and Zaher Al-Sulaimani
Published online: 15/11/1993

Keywords: Adapids; Afro-Arabian plate; Early Oligocene; New taxa; Primates; Trans-Tethyan dispersals

https://doi.org/10.18563/pv.22.4.141-196

  Abstract

    Two new species, Omanodon minor n. g., n. sp. and Shizarodon dhofarensis n. g., n. sp., known from fifteen isolated teeth, are described here as the first adapiform primates (?Anchomomyini) recognizable to date in the Taqah material (early Oligocene of Sultanate of Oman).

    Omanodon minor n. g., n. sp. displays special morphological similarity to the adapid tribe Anchomomyini from the Eocene of Europe, and especially to the Anchomomys lineage. Resemblances with the extant lemurifonn Microcebus are also noticeable and could be regarded as supporting Schwartz & Tattersall (1983) hypothesis of special relationships between the anchomomyine adapids and the cheirogaleid lemuriformes. However, these morphological affmities can be interpreted, altematively, as the results of parallelisms: important differences in upper molars indicate that the resemblances of cheirogaleids and Omanodon minor n. g., n. sp. are indeed probably due to parallelisms. Phyletic relationship of O. minor n. g., n. sp. to Anchomomyini is finally the most likely hypothesis.

    Shizarodon dhofarensis n. g., n. sp., although much more poorly known, is closely related to Omanodon minor n. g., n. sp., at least at a familial level. The general morphology of this species suggests
    also a close link with adapid Anchomomyini, although precise relationships within this tribe remain obscure. Interesting resemblances of Shizarodon dhofarensis n. g., n. sp. to Djebelemur martinezi lower molars (early Eocene of Tunisia) are also noticeable. These resemblances are even stronger than those betwen Omanodon minor and Djebelemur martinezi. However the very bunodont upper molars referred to D. martinezi are unusual for adapids, and there are moreover some notable differences in their lower molars. Thus resemblances in Djebelemur and Shizarodon are probably due to paralellisms.

    Because of the fragmentary nature of the material and of possible parallelisms, the systematic position of Omanodon and Shizarodon within adapiformes cannot however yet be established definitively. 


  PV article infos

Published in Vol. 22, Fasc. 4 (1993)

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Revision der Equoidea aus den Eozänen Braunkohlen des Geiseltales bel Halle (DDR).
Jens L. Franzen and Hartmut Haubold
Published online: 15/04/1986

Keywords: Eocene; Europe; Mammalia; Perissodactyla; Stratigraphy; taxonomy

https://doi.org/10.18563/pv.16.1.1-34

  Abstract

    The dentitions as well as one complete and several partial skeletons of Equoids from the Eocene lignite beds of the Geiseltal locality are revised. Instead of 13 species distinguished up to now 3 chronoclines with 5 species and 3 separate species are recognized (text. fig. 1). Propalaeotherium hassiacum HAUPT, 1925 is evolving into Propalaeotherium isselanum (CUVIER, 1824) between the levels of the « obere Unterkohle ›› and the « untere Mittelkohle ›› of the Geiseltal section. Propalaeotherium argentonicum GERVAIS, 1849 is shown to be present in the « untere Unterkohle ››, whereas Lophiotherium pygmaeum (DEPERET,1901) occurs in the « obere Mittelkohle ›› and in the « oberes Hauptmittel ››. Plagiolophus cartieri STEHLIN, 1904 appears during the transition from the « Mittelkohle ›› into the « Oberkohle ›› as the earliest true Palaeothere. Therefore the « Oberkohle ›› is already regarded as Upper Eocene. This is corroborated by the occurrence of a phyletic descendant of Propalaeatherium parvulum (Propalaeotherium n.sp.) in the middle and upper "Oberkohle " because this species appears otherwise for the first time at the mammal level of Lissieu. On the other hand Propachynolophus gaudryz (LEMOINE, 1878) described by Matthes (1977) from the « untere Unterkohle ›› turns out te be in fact a Phenacodont. Thus the decisive argument for classifying the « untere Unterkohle ›› as Lower Eocene has to be dropped. Biostratigraphically the « Unterkohle ›› and the «Basishauptrnittel ›› correspond with the lower Middle Eocene (mammal level of Messel), whereas the «unteres Hauptmittel ›› and the « untere Mittelkohle ›› are equivalent to the middle part of the middle Eocene (mammal level of lssel), and the « obere Mittelkohle ›› together with the « oberes Hauptmittel ›› coincide with the upper Middle Eocene (mammal level of Bouxwiller). 


  PV article infos

Published in Vol. 16, Fasc. 1 (1986)

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The lower Miocene artiodactyls of Tagai bay, Olhon island, lake Baikal (Russia)
Inesa Vislobokova Logo
Published online: 20/05/1994

Keywords: Artiodactyls; Mammals; Miocene; Siberia

https://doi.org/10.18563/pv.23.1-4.177-197

  Abstract

    The mammalian fauna of the Tagai locality of Olhon Island in Lake Baikal contains six artiodactyls:
    Amphitragulus boulangeri, Lagomeryx parvulus, Stephanocemas sp., Palaeomeryx kaupi, Orygotherium aff. escheri, and Brachyodus intermedius. They are reported from Eastern Siberia for the first time. A description of teeth and limb-bones are given. An analysis of the systematic composition of the Tagai fauna allows it to be correlated with European faunas of the second part of the Early Miocene (Orleanian, MN 3-4) and permit suggestion of the existance of a united European-Siberian zoogeographical sub-area in the middle latitudes of Eurasia at that time. 


  PV article infos

Published in Vol. 23, Fasc. 1-4 (1994)

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Les Palaeotheridae (Perissodactyla) de la faune de Mammifères de Fons 1 (Eocène supérieur).
Jean-Albert Remy
Published online: 15/06/1967

Keywords: Anchilophus; Eocene; Pachynolophus; Palaeotheriidae; Perissodactyla

https://doi.org/10.18563/pv.1.1.1-46

  Abstract

    The locality of Fons 1, one of the fossiliferous outcrops in the late Eocene limestones of Fons-outre-Gardon (Gard), has yielded varied remains of mammals. The specimens were prepared by dilute acetic acid attack on the rock and by impregnation with an acrylic resin.
    This fauna, rich with about 20 species, can be included in the biochronologic zone of Euzet. The Palaeotheridae (sensu Simpson 1945), represented by 6 species, occupy a predominant place; Plagiolophus annectens is particularly abundant, comprising 55% of all the specimens found.
    The abundance of this species has permitted a detailed comparative study with the corresponding form from Euzet. The quantitative tests brought out a slight but highly sígnificant difference between the average dimensions of the teeth in the two populations. Moreover and in spite of the feeble rate of evolution in the Plagialophus dentition, diverse archaic particularities can be seen which permit the conclusion that the form from Fons 1 is a little the older. This conclusion is corroborated by observations on the other palaeotherids, particularly Lophiotherium aff. cervulum, whose dental evolutionary stage is intermediate between those of the corresponding forms known from Robiac and Euzet.
    A new species of Pachynolophus is described, P. garimondi n.sp., the last representative known of the genus. lts teeth are distinguished by their size, a great heterodonty, and the weakness
    of their cingula. 


  PV article infos

Published in Vol. 01, Fasc. 1 (1967)

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La région des phosphorites du Quercy
A. Cavaillé
Published online: 15/11/1974

Keywords: Quercy Phosphorites

https://doi.org/10.18563/pv.6.1-2.5-19

  Abstract

    L'exploitation des phosphates s'est produite surtout de 1890 à 1914 de Saint-Antonin à Cajarc, sur le Causse de Limogne, dont l'histoire géologique et morphologique peut expliquer les conditions de gisement du minerai, et aussi la découverte des nombreux, variés et beaux fossiles qu'on a extrait des poches en même temps que la phosphorite. Le Causse de Limogne est le nom donné par les géographes au plateau calcaire, faisant partie des Causses du Quercy, et compris entre la vallée du Lot au Nord et celle de "Aveyron au Sud". En fait, le nom de "causse" désigne localement un terroir, un paysage, à sous-sol de calcaire, à sol peu épais, qui s'oppose aux sols argileux des « terreforts » et aux sols légers et profonds des "boulbènes". Chaque communauté agricole distinguait ainsi son causse, par exemple le causse de Caylus, le causse de Limogne ou le causse de Cajarc. C'est par extension que l'appellation Causse de Limogne désigne tout un petit pays. La présence des poches à phosphate déborde un peu vers le Nord la vallée du Lot, et vers l'Est le Causse de Limogne proprement dit (Causse de Villeneuve).   


  PV article infos

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

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Book review : Dr. Robert R. REISZ, 1986.  Encyclopedia of Paleoherpetology,  Volume: 17A: Pelycosauria.
Jean-Yves Crochet
Published online: 20/06/1987

Keywords: Book review; Paleoherpetology

https://doi.org/10.18563/pv.17.2.75-76

  Abstract

    L’Encyclopedia of Paleoherpetology, Part 17A : Pelycosauria de Robert R. Reisz (1986) offre une synthèse complète des synapsides les plus primitifs et les plus anciens, essentiels pour comprendre l’évolution précoce de ce groupe majeur de vertébrés. L’ouvrage commence par un historique, suivi d’une analyse ostéologique détaillée du crâne, du squelette axial et appendiculaire. 


  PV article infos

Published in Vol. 17, Fasc. 2 (1987)

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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 Logo, Jean-Yves Crochet, Serge Legendre Logo, Jacques Michaux and Bernard Sigé
Published online: 31/10/1986

Keywords: Europe; First occurence; Megachiroptera; Middle Miocene; Teeth

https://doi.org/10.18563/pv.16.3.173-184

  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. 


  PV article infos

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

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Owls, caves and fossils. Predation, preservation and accumulation of small mammal bones in caves, with an analysis of the Pleistocene cave faunas from Westbury-Sub-Mendip, Somerset, UK, par Peter Andrews, 1990. The University of Chicago Press, 232 p.
Christiane Denys Logo
Published online: 17/12/1992

Keywords: caves; owls; preservation; taphonomy

https://doi.org/10.18563/pv.22.1.49-50

  Abstract

    La taphonomie (science de l'enfouissement et de la fossilisation) des micromammifères a trop souvent été négligée par rapport à celle des grands mammifères. Or, pour expliquer les concentrations parfois très importantes de microfossiles dans les grottes et les sites préhistoriques il faut connaître les mécanismes qui concourrent actuellement à favoriser les accumulations de ces derniers. C'est le but de l'ouvrage de Peter Andrews qui se décompose en deux parties. 


  PV article infos

Published in Vol. 22, Fasc. 1 (1992)

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Premières données sur les carnivores fissipèdes provenant des fouilles récentes dans le Quercy
Louis de Bonis Logo
Published online: 15/11/1974

Keywords: Carnivores; Quercy Phosphorites

https://doi.org/10.18563/pv.6.1-2.27-32

  Abstract

    Cet article présente les premières données sur les Carnivores fissipèdes des Phosphorites du Quercy, issues de fouilles récentes (1971-1972). Les fossiles se répartissent de l'Oligocène inférieur à supérieur. 


  PV article infos

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

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Rongeurs Miocènes dans le Valles-Penedes 2 : Les rongeurs de Castell de Barbera
Jean-Pierre Aguilar, Jordi Agusti Logo and J. Gibert
Published online: 20/04/1979

Keywords: Castell de Barbera; Miocene; Rodents; Valles-Penedes

https://doi.org/10.18563/pv.9.1.17-32

  Abstract

    The rodent-fauna (Cricetidae and Gliridae) recently found at Castell de Barbera (Spain) is similar to those from the other locslities of the Valles - Penedes - Can Ponsic 1 and Can Llobateres - : same composition and similar evolutionary level of the different species. On the other hand this fauna is different from those of Upper Vindobonian and Vallesian localities of the Calatayud - Teruel area. Castell de Barbera has an intermediate chronological position between the localities of Anwil (Switzerland) and Can Ponsic 1. It is still not possible to validate or invalidate the initial attribution based on absence of Hipparion of Castell de Barbera to the Upper Vindobonian. 


  PV article infos

Published in Vol. 09, Fasc. 1 (1979)

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Nouveaux gisements à rongeurs dans les molasses oligo-miocènes de la région toulousaine
Francis Duranthon Logo
Published online: 11/02/1993

Keywords: Cricetidae; Eomyidae; GIiridae; Miocene; Oligocene; Rodents; Sciuridae; Southern France

https://doi.org/10.18563/pv.22.2-3.113-136

  Abstract

    The fauna from three new rodent localities (Castelmaurou, Grépiac-carrière et Grépiac-rive gauche) from Oligo-Miocene molasses of the Toulouse area is described. The one from Colomiers is completed. 11 species belonging to 4 families (Cricetidae, Eomyidae, Gliridae, Sciuridae) are present. The Miocene localities of Grépiac-carrière and Colomiers are correlated with Balizac, La Brète, Lambert and Lespignan. Grépiac-rive gauche is just a little older than these sites. Castelmaurou is somewhat younger than La Milloque and belongs to Oligocene. 


  PV article infos

Published in Vol. 22, Fasc. 2-3 (1993)

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Anatomie du membre antérieur chez un chiroptère Molossidé (Tadarida sp.) du Stampien de Cereste (Alpes-de-Haute-Provence).
Bernard Sigé
Published online: 01/01/1971

Keywords: Chiroptera; Molossidae; Oligocene

https://doi.org/10.18563/pv.4.1.1-38

  Abstract

    The present study describes in detail the anterior limb osteology of a molossid chiropteran of the genus Tadarida, from Céreste, a Stampian locality in the Apt-Forcalquier Oligocene basin already known for its fishes, plants and insects.

    A comparision with the Miocene forms T. srehlini from Saint-Géraud localities and T. sp. from Württemberg, also with the recent forms T. teniotis and Eumops perotis, does not show any clear morphological differences between the Tertiary and Recent Tadarida, indicating a rather noticeable anatomical stability, not exceptionnal indeed among Chiropterans. The Céreste fossil exhibits however slightly primitive wing proportions if compared to the Saint Gérand Aquitanian species.

    Several remarks deal with the peculiar relationships between the ecology of the molossids and their kind of fossilisation, frequently associated with sedimentary facies of the lacustrine type.
      


  PV article infos

Published in Vol. 04, Fasc. 1 (1971)

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Révision des Chiroptères Lutériens de Messel (Hesse, Allemagne).
Donald E. Russell and Bernard Sigé
Published online: 04/04/1970

Keywords: Chiroptera; Lutetian; Messel

https://doi.org/10.18563/pv.3.4.83-182

  Abstract

    The revision of the Lutetian chiropterans from Messel, first described by Revilliod in 1917, is based on the anatomy of the teeth and the skeleton.  A figuration or refiguration of thematerial utilized accompanies the new description, which goes beyond that of the original monograph.
    The study shows a certain variability of the dental structure within the genera Palaeochiropteryx Revilliod and Archaeonycteris Revilliod,  as well as a general resemblance of the two forms. The morphology of the teeth permits, however, the verification of the validity of the different species: Palaeochiropteryx tupaiodon Revilliod, P. spiegeli Revilliod, Archaeonycterís trigonodon Revilliod, and Archaeonycteris revilliodi, n. sp.
    Some differences of the skeletal and dental anatomy tend to indicate a stage of evolution less advanced for the genus Archaeonycteris.
    The comparison of the chiropterans of Messel with the principal groups of living chiropterans, as well as with different Eocene fossíls (notably Cecílionycteris Heller and Icaronycteris Jepsen) leads to a more precise idea of the anatomy of primitive chiropterans. This comparison also permits the proposition that the oid forms so far described by integrated in a superfamily, the Palaeochiropterygoidea and allows   a general phylogenetic hypothesis to be advanced for the order Chiroptera. 


  PV article infos

Published in Vol. 03, Fasc. 4 (1970)

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Evolution des Aplodontidae Oligocènes Européens
Norbert Schmidt-Kittler and Monique Vianey-Liaud Logo
Published online: 01/10/1979

Keywords: Aplodontidae; Europe; Oligocene

https://doi.org/10.18563/pv.9.2.33-82

  Abstract

    Until now Aplodontidae of the European Oligocene have been documented by four species only. The phylogenetic relations remained obscure. as the distribution of only one species has been known in some detail. New material made it possible to define the stratigraphic range of two of the already existing species (Plesispermophilus angustidens, Sciurodon cadurcense) and to follow their development during the Oligocene beginning with the event of the « Grande Coupure ››. Sciurodon remained nearly without change until the end of the Middle Oligocene. Plesispermophilus angustidens split into two distinct phyletic lines, one of which (P. macrodon n. sp.) reaching considerable size, is represented till the beginning of the Upper Oligocene (Pech de Fraysse, Gaimersheim). The other line leads to Plesispermophilus ernii (basal Upper Oligocene of Burgmagerbein 1. terminal Upper Oligocene of Coderet). Besides the already known forms a new small-sized species (P. atavus n. sp.) is described, which by its primitive features closely resembles the genus Plesispermophilus. Two other small-sized species already known from the Upper Oligocene (? P. argoviensis) and Lower Miocene (? P. descedens) seem to be closely related to the new species. It cannot be decided whether they are descendents of this line or have developed independently, because of their poor fossil record.
    Comparison of the evolutionary modalities in the different phylogenetic lines reveals general trends. the most striking of which is the complication of the tooth pattern by the development of additional crests. In the lower molars the cusps diminuate in size and are more and more transformed into ridges. ln addition new connection between the crests appear. in the upper molars, the « selenodont » shape of the teeth becomes more and more dominant, and in the two main evolutionary lines of Plesispermophilus the metaconulus becomes duplicated. A further evolutionary trend is the size increase of the premolars compared to the molars, which is even more pronounced in the Miocene Aplodontidae.
    Phylogenetic relations between the primitive Plesispermophilus and certain « prociurines ›› of Northern America as well as between Plesispermophilus (P. angustidens) and more progressive forms of the Upper Oligocene (P. ernii, P. macrodon n. sp.) can be documented. In this light, the taxonomic distinction between Prosciurinae (bunodont) and Allomyinae (selenodont) sensu Rensberger 1976 can be shown to be artificial, because it separates forms from each other, which are evidently closely related. Consequently the separation into two subfamilies has been abolished. 


  PV article infos

Published in Vol. 09, Fasc. 2 (1979)

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Page 9 of 19, showing 20 record(s) out of 366 total