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 Les Affinités de Nyctereutes megamastoides (Pomel), canidé du gisement Villafranchien de Saint-Vallier (Drôme, France).
R. Martin
Keywords: Canidae; Nyctereutes; Villafranchian

doi: 10.18563/pv.4.2.39-58
 
  Abstract

    Nyctereutes megamastoides (Pomel) from the Villafranchian of the Auvergne and from Saint-Vallier presents cranial and dental characters sufficiently close to those of the late Pliocene canid from Perpignan (Roussillon), described by Depéret under the specific name of Canis donnezani belonging to the same genus Nyctereutes. The extinction of the European "Nyctereutes" group seems due to the too great alimentary specialization of this canid, whereas the Asiatic lineage represented in the Villafranchian by Nyctereutes sinensis Schlosser and at present by Nyctereutes procyonider Gray was able to maintain itself probably by means of a profound change in its alimentary regime. 


  Article infos

Published in Vol. 04, Fasc. 2 (1971)

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Middle Eocene rodents from the Subathu group, Northwest Himalya.
Kishor Kumar, Rahul Srivastava and Ashok Sahni
Keywords: Chapattimyidae; Eocene; evolution; India; Rodentia; Subathu group; Systematics
 
  Abstract

    Extensive collecting in previously known and new Middle Eocene rodent localities in the Subathu Group of the Rajauri and Reasi districts, Jammu and Kashmir (northwest Himalaya, India) has yielded over 500 isolated cheek teeth, numerous incisors and cheek tooth fragments, and two mandibular fragments with M/1-M/3. An analysis of this additional material and a restudy of that reported earlier from the Metka (Rajauri) area has revealed the presence of diverse Middle Eocene ctenodactyloid rodents in India. The assemblage comprises six genera and twelve species, viz.., Bírbalomys woodi, B. ibrahimshahi, B. sondaari, Basalomys vandermeuleni, B. ijlsti, B. lavocati, Chapattimys wilsoni, C. debruijni, Gumbatomys asifi, cf. Advenimus bohlini, cf. Petrokoslovia sp. indet. 1 and cf. Petrokoslovia sp. indet. 2. Most species of this assemblage are endemic to the Indian subcontinent and are referred to the Family Chapattimyidae. However, at least three taxa, viz.., cf. Advenimus bohlini, cf. Petrokoslovia sp.indet. 1 and cf. Pezrokoslovia sp. indet. 2 show close affinities with their Central and Eastern Asiatic contemporaries and are attributed to the Family Yuomyidae. The dentitions of most of the Middle Eocene rodents from India are described here in better detail thus providing more precise characterization than was available earlier. The taxonomie status of Basalomys, formerly a subgenus of Birbalomys has been raised to that of a genus. Basalomys vandermeuleni is here designated as the type species of Basalomys in place of B. ijlsti. The rodent assemblage from the Subathu Group is specifically similar to that from the coeval Kuldana Formation of Pakistan. The absence of Birbalomys ibrahimshahi and cf. Advenimus bohlini in Pakistan is related to sampling bias. The identifications of the Early Eocene rodents from Barbara Banda, Pakistan have been reexamined and the familial assignments of some of the Early and Middle Eocene rodents from Central and Eastern Asia have been discussed and reviewed in the light of recent discovery of early rodents in Mongolia.

      


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

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Die Referenzfauna des Geiseltalium, MP levels 11 bis 13 (Mitteleozan, Lutetium)
Hartmut Haubold
Keywords: Eocene; Geiseltal; Land mammal ages; Mammalian reference levels
 
  Abstract

    The Middle Eocene Fossillägerstätte of the Geiseltal lignite beds near Halle/S. (German Democratic Republic) is the reference locality of the European land mammal age Geiseltalian and of the Mammalian Paleogene reference levels MP 11 - MP 13. Due to this importance a reinvestigation is given of the lithostratigraphical development of the Geiseltal beds and of their vertebrate sites. The last are genetically related to the southwest border of the Geiseltal depression and the influx of carbonate-rich waters. The geographical distribution and stratigraphical position of the fossiliferous sites depends on subrosive and tectonically controlled distribution of coal seams. The geological factors and the known stratigraphical guide of some mammalian species suggest corrections of the age of some sites. Four of the alltogether five coal bearing phases contain the 35 sites with mammalian remains. By the distribution of the around 69 mammal species are characterized, with 5 faunal steps ranging from MP 11 to MP 14 or over the Geiseltalian up to the Lower Robiacian. Well distant are the faunas of MP 11 and MP 12. Beginning with MP 12 up to MP 13/14, the fossil record is very frequent by 27 sites. This evidence coincides somewhat more with the concept of land mammal ages compared to that of the punctual mammalian reference levels. 


  Article infos

Published in Vol. 19, Fasc. 3 (1989)

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Le genre Microstonyx en Espagne et ses relations avec les autres espèces du même genre hors d'Espagne
Juana M. Golpe-Posse
Keywords: Microstonyx; Spain; Suidae
 
  Abstract

    The genus Microstonyx was found only in the north eastern part of Spain : M. antiquus, referable to the
    Eppelsheim type, from the pyrenean basins ; M. antiquus, more progresive, from the Vallès Basin : M. major-erymanthius group, from the Teruel-Ademuz Area and from Pieru (Penedès Basin).

      


  Article infos

Published in Vol. 9, Ext (1980)

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Morphotypes dentaires actuels et fossiles des Chiroptères Vespertilioninés. 1e partie: Etude des morphologies dentaires
Henri Menu
Keywords: bats; Dental morphology; fossils; PHYLOGENY; recent; Systematics
 
  Abstract

    The classifications of the recent vespertilionine bats were made wihtout taking in account the teeth morphology; this resulted in a reduction of the possibilities of comparison with the available fossils. The generalized use of dental formulae was abusive: this contributed to the admission of artificial genera. These conditions have long delayed the consideration of characters able to frame the phylogeny of the sub-family. In the first part of the study, the teeth morphologies are described and analysed. morphological reference types are established for each upper and lower tooth: they should make an easier elaboration of criteria for the differentiation at generic level. The position of the species in view of these criteria allows one to group them into homogeneous genera, and to appreciate the degree of relationship that the latter have between them. The second part of the study (next publicationà will develop inferences dealing with systematics and phylogeny 


  Article infos

Published in Vol. 15, Fasc. 2 (1985)

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Mode de vie et affinités de Paschatherium (Condylarthra, Hyopsopontidae) d'après ses os du tarse
Marc Godinot, Thierry Smith and Richard Smith
Keywords: Astragalus; Calcaneum; Condylarthra; Eocene; Functional morphology; Paschatherium; PHYLOGENY
 
  Abstract

    Tarsals that can be confidently attributed to Paschatheríum dolloi from Dormaal (Belgium) are described. The astragalus is short; its broad neck is set at an angle of 30 degrees to the trochlea. The trochlea is pulley-shaped and proximally extended. There is no astragalar foramen. The medial tibial facet extends distally in a cup deeply excavated in the neck and buttressed. The sustentacular facet extends toward the navicular facet but is not fully confluent with it. The calcaneum bears a proximo-distally extended proximal facet for the astragalus. A relatively large peroneal tubercle projects from the body, and is situated distally. Functionally, the trochlea indicates extensive flexion-extension movements of the foot. Calcaneo-astragalar facets indicate sliding and rotation between the two tarsals. The inclination of the navicular facet suggests frequent foot inversion. The peroneal tubercle reflects good muscular capacities for foot rotation. Overall morphology is interpreted as a scansorial adaptation similar to that of sciurids.Comparisons are made with the tarsals of Macrocranion vandebroeki from Dormaal and Hyopsodus paulus from the Bridgerian of Wyoming. Some similarities between the astragali of Paschatherium and Macrocraníon (trochlea) are interpreted as convergences for rapid locomotion. However absence of mobility at the lower ankle and midtarsal joints in M. vandebroekzi suggests that this species was cursorial, as is known for M. tenerum from Messel. Similarities in the calcanea of Paschatherium and Hyopsodus are probably the result of close phylogenetic relations, and confirm the placement of Paschatherium in the hyopsodontids. The differences in the calcanea of Paschatherium and Macrocranion underline that Paschatherium is distinct from erinaceomorph insectivores. The differences in astragalar morphology between Paschatherium and Hyopsodus show that a marked adaptive divergence separates the two genera. We speculate about the common occurrence of a deep tibial cup (“cotylar fossa”) and a pulley-shaped trochlea in Paschatherium and hyracoids, suggesting that an adaptive scenario similar to that having led to Paschatherium (scansoriality) might explain the acquisition of the peculiar hyracoid tarsal characters; such a scenario contradicts the concept of Pantomesaxonia. Other peculiar characters of Hyopsodus suggest that hyopsodontids might be given more consideration in the search for hyracoid (and tethythere) origins. 


  Article infos

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

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Neue Beobachtungen zum Schädel-und Gebiss-Bau der Paulchoffatiidae (Multituberculata,Ober-Jura).
Gerhard Hahn
Keywords: Dentition; Paulchoffatiidae; Portugal; Skull structure; Upper Jurassic
 
  Abstract

    The ventral face of the Paulchoffatiinae skull (Multituberculata, Lower Kimmeridgian, Portugal) is new reconstructed. Some details hitherto unknown are added, as the presence of jugals, the structure of the palatine and the extension of the pterygoids. The situation of the m2/ is discussed. Kielanodon hopsoni n. g., n. sp. is erected, known by its upper p3-5/. From Guimarotodon leiriensis the mandible with its dentition is made known. New informations concerning the milk-dentition and the replacement of teeth are also added. 


  Article infos

Published in Vol. 17, Fasc. 4 (1987)

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La Poche à phosphate de Ste-Neboule (Lot) et sa faune de vertébres du Ludien Supérieur. 3- Chéloniens
France de Broin
Keywords: Eocene; Quercy Phosphorites
 
  Abstract

    The few remains recently collected at Ste Néboule (upper Eocene) belong to three genera: the Testudinid Ergilemys, of which it is the oldest occurence in Western Europa, probably Palaeochelys and an unpublished genus, which is peculiar to the Phosphorites du Quercy. Some statements are made on the chelonian fauna as a whole in that région. After the study of some characters proper to the genus Ergilemys, some remarks are made concerning its antecedents and descendants. 


  Article infos

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

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Die Ohr-Region der Paulchoffatiidae (Multituberculata, Ober-Jura).
Gerhard Hahn
Keywords: Multituberculata; Ober-Jura; Paulchoffatiidae; Petrosum; Portugal
 
  Abstract

    The petrosal of the Paulchoffatiidae HAHN, 1969 is described and compared with that of younger multituberculates and of other Mesozoic mammals. The "Morrison petrosal", described by Prothero (1983), is also discussed; it probably belongs to the multituberculates. The reconstruction of the ventral side of the Paulchoffatiinae-skull, given by Hahn in 1987, is completed by addition of the otic and the occipital region. 


  Article infos

Published in Vol. 18, Fasc. 3 (1988)

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Fallen in a dead ear: intralabyrinthine preservation of stapes in fossil artiodactyls
Maeva J. Orliac and Guillaume Billet
Keywords: allometry; bony labyrinth; inner ear; middle ear ossicles

doi: 10.18563/pv.40.1.e3
 
  Abstract

    The stapes is the last of the middle ear ossicle chain and the smallest bone of the mammalian skeleton. Because it rests on the membrane of the fenestra vestibuli during life, the stapes may often fall within the bony labyrinth cavity when soft structures decay after death. In this work, we highlight the unexpected role that the bony labyrinth plays in the preservation of the stapes. Systematic investigation of the bony labyrinth of 50 petrosal bones of extinct and extant artiodactyls led to the discovery of eight cases of “intralabyrinthine” stapes. Three dimensional reconstructions of these stapes allow documenting stapes morphology of four extinct artiodactyl taxa: Microstonyx erymanthius (Suidae), Elomeryx borbonicus (Hippopotamoidea), ?Helohyus plicodon (Helohyidae), and an undetermined Cainotheriidae; and four extant ones Choeropsis and Hippopotamus (Hippopotamidae), and Tayassu and Phacochoerus (Suoidea). ?Helohyus plicodon from the Middle Eocene documents the oldest stapes known for the order Artiodactyla. Morphological study and metric analyses of our sample of artiodactylan stapes show that stapes are likely to carry relevant phylogenetic characters/signal within artiodactyls, and a potential Euungulata signature. 


  Article infos

Published in Vol.40-1 (2016)

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S.I. Data
Origins of avian reproduction: answers and questionsfrom dinosaurs.
David J. Varricchio and Frankie D. Jackson
Keywords: Avian reproduction; clutch; dinosaurs; egg size; nests; oviducts; parental care
 
  Abstract

    The reproductive biology of living birds differs dramatically from that of other extant vertebrates. Distinctive features common to most birds include a single ovary and oviduct, production of one egg at daily or greater intervals, incubation by brooding and extensive parental care. The prevalence of male parental care is most exceptional among living amniotes. A variety of hypotheses exist to explain the origin of avian reproduction. Central to these models are proposed transitions from a condition of no care to maternal, paternal or biparental care systems. These evolutionary models incorporate a number of features potentially preservable or inferable from the fossil record (integument, skeletal adaptations for flight, egg and clutch size, nest form, hatchling developmental stage, the number and function of oviducts, and the mode of egg incubation). Increasing availability of data on dinosaur reproduction provides a means of assessing these hypotheses with fossil evidence. We compare dinosaur data to a selection of models that emphasize maternal, paternal or biparental care. Despite some congruence with dinosaur features, no single model on the evolution of avian reproduction conforms fully to the fossil record, and the ancestral parental care system of birds remains ambiguous. Further investigation into dinosaur parental care, nest structures, clutch geometry, egg-pairing, eggshell porosity, and embryo identification may eventually resolve these issues.  


  Article infos

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

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 La poche à phosphate de Ste-Néboule (Lot) et sa faune de vertebres du Ludien supérieur. 9- Primates et Artiodactyles
Jean Sudre
Keywords: Eocene; Quercy Phosphorites
 
  Abstract

    La faune d'artiodactyles de Ste-Néboule, qui comprend neuf espèces, présente de nombreux
    points communs avec les faunes habituellement rattachées au Ludien supérieur, telles celles de La Débruge ou de Montmartre. A l'inverse de ces localités, on ne connaît pourtant, à Ste-Néboule, ni Oxacronae, ni Anoplotheriinae. Parmi les espèces du gisement se trouve une nouvelle espèce du genre Mouillacitherium (M. schlosseri n. sp.), cette forme devant être interprétée comme le dernier représentant du rameau. Nous faisons connaître par ailleurs la presque totalité de la denture du Dacrytherium saturninii, espèce qui était à ce jour très imparfaitement documentée. Ste-Néboule est, d'autre part, la seule localité où l'on peut signaler l'association probable de deux lignées du genre Amphimeryx. Les primates sont peu diversifiés à Ste-Néboule, puisque le groupe est limité au seul genre Adapis. Les genres Microchoerus et Pseudoloris, que l'on sait pourtant être représentés dans des gisements dâge voisin (Microchoerus ornatus à San Cugat de Gavadons et Mormont-Entreroches, Pseudoloris reguanti à San Cugat de Gavadons, Pseudoloris cf. reguanti à Neustadt ; cf. Louis et Sudre 1975) sont absents dans les faunes du Quercy de cette période. 


  Article infos

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

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Latest Early-early Middle Eocene deposits of Algeria (Glib Zegdou, HGL50), yield the richest and most diverse fauna of amphibians and squamate reptiles from the Palaeogene of Africa
Jean-Claude Rage, Mohamed Adaci, Mustapha Bensalah, Mahammed Mahboubi, Laurent Marivaux, Fateh Mebrouk and Rodolphe Tabuce
Keywords: Africa; Algeria; amphibians; Eocene; squamates

doi: 10.18563/pv.44.1.e1
 
  Abstract

    HGL50 is a latest Early-early Middle Eocene vertebrate-bearing locality located in Western Algeria. It has produced the richest and most diverse fauna of amphibians and squamate reptiles reported from the Palaeogene of Africa. Moreover, it is one of the rare faunas including amphibians and squamates known from the period of isolation of Africa. The assemblage comprises 17 to 20 taxa (one gymnophionan, one probable caudate, three to six anurans, seven ‘lizards’, and five snakes). Two new taxa were recovered: the anuran Rocekophryne ornata gen. et sp. nov. and the snake Afrotortrix draaensis gen. et sp. nov. The locality has also yielded the first confirmed anilioid snake, the first Palaeogene gymnophionan, and probably the first caudate from the Palaeogene (and possibly from the Tertiary) of Africa. The presence of a caudate at that time in Africa would be of particular interest; unfortunately, the available material does not permit a definitive identification. The fauna comprises Gondwanan and more specifically West Gondwanan vicariants, probably autochthonous groups and a Eurasian immigrant (assuming that the identification of the caudate is accurate). The fauna from HGL50 is clearly distinguished from the few other Eocene assemblages of Africa. However, if this results largely from differences in geological ages, geographic positions of the localities and mainly differences in environments took a part in the composition of the faunas. 


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Published in 44-1 (2021)

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Contributions à l'étude des micromammifères du gisement Miocène supérieur de Montredon (Hérault). 4 - Les chiroptères
Bernard Sigé
Keywords: Chiroptera; Hérault; Late Miocene; Micromammals; Montredon
 
  Abstract

    The Montredon local fauna yielded very rare bats, represented by damaged isolated teeth. Only a few documents are available for this period of the European Neogene. ln this poor state of knowledge, the material represents three undetermined species, a supposed molossid and two vespertilionids. 


  Article infos

Published in Vol. 12, Fasc. 3 (1982)

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Contribution à la classification des Pistes de Vertébrés du Trias : les types du Stormberg d'Afrique du Sud (2 ème Partie: le Stormberg supérieur - 1. Le biome de la zone B/1 ou niveau de Moyeni: ses biocénoses).
Paul Ellenberger
Keywords: biocenosis; Footprints; South Africa; Stormberg; Trias
 
  Abstract

    Les Pistes de Vertébrés du Stormberg Supérieur ("Trias terminal à Rhétien"), ou Quthingien

    Si les zones du Stormberg inférieur se sont révélées contenir de nombreuses traces, surtout dans les faciès dits "Molteno moyen et supérieur", représentant apparemment la base du Keuper, il est frappant de voir pratiquement l'ensemble de cette grosse faune "Molteno" disparaître avec la fin de cette période, que nous avons appelée le "Maphutsengien".

    Dès les premières zones du Stormberg supérieur, que nous nommons le"Quthingien" la zoocénose et la phytocénose, en même temps que les données d'ensemble manifestées par l'environnement, sont modifiées. Nous ne verrons plus guère de dépôts marécageux à flore riche et variée, parfois même luxuriante. Les fougères elles-mêmes ont disparu. Elles sont remplacées par de maigres plantes, aux feuilles très souvent filiformes qui paraissent témoigner d'un climat continental. Le sol est devenu de plus en plus rouge, avec des variations latérales beaucoup plus accusées. Les fleuves amenant des galets des monts du "Grand Sud" ont tari. La faune va en subir les conséquences. Certaines des espèces se révèleront sautillantes ou coureuses, pour un grand nombre plus légères et pour la quasi-totalité d'apparence carnivore ou entomophages, les phytophages devant se contenter d'un régime ingrat,difficile ou à tout le moins irrégulier,les dépôts le montrent.

    C'est dans ces conditions que s'inaugure notre Etage nouveau,quelque peu discordant sur les zones A/5, A/6 ou A/7 du Stormberg inférieur (Maphutsengien). Le Stormberg supérieur (ou Quthingien) commence avec le paléopaysage remarquable dit de Moyeni, que nous allons maintenant étudier, typologiquement, avec ses homologues du même âge. Quelques 38 types d'animaux tous nouveaux vont défiler à nos yeux lors de la zone de base de cet Etage, ou zone B/1.

    L'on nous avait proposé d'intituler ce Ile Tome de la série : "La grande Dalle de Moyeni et ses homologues. Paléo-spectacles, scènes et paysages animaux au Lesotho à l'approche du Trias finissant". Nous avons préféré garder le sous-titre plus haut, peut-être plus prosaïque.

    Un llle Tome est en préparation : "Les développements ultérieurs et terminaux de la faune du Gondwana".

      


  Article infos

Published in Vol. 6, Ext (1974)

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Eggshell microstructure and porosity of the Nicobar scrubfowl (Megapodius Nicobariensis, great Nicobar island, India)
Géraldine Garcia, Ashu Khosla, Ashok Sahni and Monique Vianey-Liaud
Keywords: conductance porosity; eggshell microstructure; incubation conditions; Megapodes

doi: 10.18563/pv.36.1-4.75-88
 
  Abstract

    The eggshell of Nicobar scrubfowl (Megapodius nicobariensis) is described for the first time. Its egg porosity is calculated and discussed with data from several taxa (another megapode, some extant and fossil reptiles including a titanosaur group) in order to compare incubation types with eggshell structure. Eggshell microstructure reflects first phylogenetic traits and does not seem to have developed major adaptative features due to the incubation conditions, except for the pore canals. 


  Article infos

Published in Vol. 36, Fasc. 1-4 (2008)

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 Contributions à l'étude de l'anatomie crânienne des rongeurs. 1- Principaux types de cricétodontinés
Jean-Louis Hartenberger
Keywords: Cricetodon; Cricetodontinae; Miocene

doi: 10.18563/pv.1.2.47-64
 
  Abstract

    Description, for the first time, of the skull of Ruscinomys Depéret on the basis of a nearly complete specimen, and description of a new facial part of a Megacricetodon Fahlbusch skull (material from upper Miocene, Spain). New description of the skull (facial part) of " Cricetodon" incertum Schlosser on the basis of the specimen from the Oligocene of Quercy phosphorites already published by S. Schaub.
    Comparison of the skull of “ C.incertum with that of the asiatic genus Cricetops Matthew and Granger and that of the North-American Eumys Leidy. These three genera of similar age display very distinct characteristics; their common origin must go back to the Eocene, as Wood believed.
    Comparisons of the auditory regions of Ruscínomys and of Megacricetodon where important differences are noted. Comparison of the Cricetodontines from European Miocene with contemporary Cricetines. Contrary of the opinion held by Schaub, their anatomical differences do not seem suflicient to warrant the contention that none of the Cricetines derive from a form close to one of the known Cricetodontines. 


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Published in Vol. 01, Fasc. 2 (1967)

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Rythme et modalités de l'évolution chez les rongeurs à la fin de l'Oligocène-leurs relations avec les changements de l'environnement.
Bernard Comte
Keywords: Environment; evolution; Oligocene; Rodents; Systematics
 
  Abstract

    The analysis of oxygene isotope variations as well as paleobotanical data suggest that the Oligocene/Miocene boundary corresponds to a transitional period marked by floristical and climatic variations. During this period, the pyreneo-alpine tectonics has contribued to modify the geography and western Europe landscapes. Faunal changes (appearances, extinctions, migrations) are observed in different mammalian groups, notably in the rodents. A study of the evolutionary trends and patterns in paleogene rodents is involved for the period ranging from level MP 28 of the Late Oligocene to the Early Miocene, including the Oligo-Miocene boundary.
    The Rodents fauna from the sites of Venelles (Bouches-du-Rhône District, France) and Thezels (Lot, France), previously mentionned in litterature, have been studied. The first description of the Eomyidae of La Milloque (MP 29) has been completed. These faunas are compared to those from various localities dating from the considered period. In La Milloque, a new representative of the Eomys species is described next to a form close to Rhodanomys hugueneyae ENGESSER, 1987. It is the Eomys milloquensis nov. sp., the likely descendant of Eomys quercyi COMTE & VIANEY-LIAUD, 1987. Two new species are also described in Thezels: Eucricetodon thezelensis nov. sp., resulting from a likely and local evolution of Eucricetodon praecursor (SCHAUB, 1925) from La Milloque, which, in the same geographic area, could be at the origin of Eucricetodon hesperius ENGESSER, 1985 from Paulhiac. Plesiosminthus admyarion nov. sp., quite distinct from Plesiosminthus schaubi VIRET, 1926, which announces Plesiosminthus myarion SCHAUB 1930. Venelles 'Plesiosminthus schaubi population is considered as a sub-species, named Plesiosminthus schaubi meridionalis nov. subsp. New phylogenetic patterns are proposed. Among the Eomyidae, a quantification of various features of the M1-2/ crown (hypsodonty, degree of abrasion, occlusal angle, state of development of the I and V anticlines), and a comparison with the occlusal diagram of the other teeth among various other populations allows a more efficient separation of Eomys and Rhodanomys genera. In Western Europe, and within this period, it finally does not seem possible to gradually connect the genus Eomys to the genus Rhodanomys. The evolution of the Eomys quercyi - milloquensis lineage seems to underline a similar evolution to that which may have led from the Eomys to the Rhodanomys form. The latter which appears totally accomplished at level MP 29 of the Oligocene is considered as an immigrant. If we compare the most representative species of the Venelles, Thezels, and Coderet sites, (i.e. Rhodanomys, Eucricetodon, Adelomyarion, Peridyromys, Plesíosminthus), it becomes impossible to confirm their biochronological separation. The noticeable differences between the populations may be interpreted as geographical variations. An explanation to these variations, and to fauna's evolution during the Late Oligocene and Early Miocene can be found in the environmental modifications, supported by isotopic, paleobotanical and sedimentologic analysis. A tentative reconstruction of the environments is attempted by the cenogram method. The analysis of the fluctuations of fauna's diversity shows variations which may be correlated to a drop in temperature at MP 29, during the Late Oligocene, followed by an increase in temperature along with an aridity phenomenom, during the basal Miocene (MN O).The confrontation of various methods give the opportunity of reconstituting and comparing the evolution of the environment of three sequences of sites chosen from different regions. Ecological affinities of various rodents' species are being examined. It is possible to consider that the integration of all the conclusions resulting from this study should lead to an explanation to the evolution of rodents for the period around the Oligocene-Miocene boundary. The site of Coderet- level 3- would be posterior to the latter, at the beginnig of the Miocene, and would mark the level MN 0 of the Aquitanian.

      


  Article infos

Published in Vol. 29, Fasc. 2-4 (2000)

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D'important restes de Diplobune minor FILHOL à Itardies (Quercy)
Jean Sudre
Keywords: Diplobune; Quercy Phosphorites
 
  Abstract

    Abstract not available 


  Article infos

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

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Contributions à l'étude du gisement Miocène supérieur de Montredon (Hérault). Les grands mammifères. 1 - Les Lagomorphes
Nieves Lopez-Martinez
Keywords: Lagomorpha; Montredon; Prolagus; Upper Miocene
 
  Abstract

    A sample of 231 isolated teeth of lagomorphs from the upper Miocene of Montredon (southern France), identified as the ochotonid Prolagus crusafonii DOPEZ, 1975, is studied, comparing it with other populations of the same species as well as with its closest species P. oeningensis (KÖNIG, 1825).
    The maintenance dining 5 m.y. of a high morphological variability in a group of non-selected features is interpreted as an evolutionary response. This may be related with the heterogeneity and probably too with the regression of the environment. 


  Article infos

Published in Vol. 18, Ext (1988)

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