233 research outputs found

    Evolution of oligo-miocene Talpids (Mammalia, Talpidae) in europe: focus on the genera Myxomygale and Percymygale n. gen.

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    New material recovered in the Oligocene locality St-Martin-de-Castillon (Vaucluse, France; MP24) provides a better knowledge of the characteristics of the species vauclusensis in its type-locality, hitherto assigned to the genus Myxomygale (Talpinae, tribe Urotrichini). In Europe, the species assigned to Myxomygale range from Late Eocene/Early Oligocene to the end of the Middle Miocene (MN 7/8). However noticeable differences can be observed in mandibles of these taxa, sometimes even coexisting in the same localities. We propose for the plesiomorphic branch (including M. vauclusensis and M. minor) a new genus, Percymygale, closely related to Myxomygale. Percymygale is consequently also assigned to the tribe Urotrichini. Today, the tribe Urotrichini (American and Japanese shrew-moles) is composed of terrestrial, semi-fossorial species, not well adapted to digging but able to climb small bushes, and foraging in grasslands, forests and covered landscapes. As a result, their limbs protrude laterally from the body (unlike in moles) and their humeri are usually longer with very limited adaptations to digging. Humeri are poorly known for Myxomygale and only fragmentary humeri are known for Percymygale n. gen. making comparisons difficult. However the muzzle development in Percymygale and Myxomygale suggests that Myxomygale was perhaps a better burrower than Percymygale

    Le travail collectif des enseignants d'université sur leurs enseignements : quelles pratiques et dans quel cadre ?

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    International audienceS'appuyant sur une enquĂȘte exploratoire menĂ©e en 2016-2017, cet article s'intĂ©resse aux pratiques de travail collectif des enseignants et enseignants-chercheurs autour de leurs enseignements. L'enquĂȘte a ainsi permis de constater que de telles pratiques existent, et d'en construire la catĂ©gorisation – mais elle a Ă©galement pu montrer que ces pratiques Ă©taient trĂšs variĂ©es entre Ă©tablissements et au sein mĂȘme de ceux-ci, ce qui rend difficile pour les enseignants la construction de pratiques de travail unifiĂ©es au long de leur carriĂšre

    Cricetidae (Rodentia, Mammalia) from the oligocene of the valley of Lakes (Mongolia): the genera Aralocricetodon, Eocricetodon, Bagacricetodon, Witenia and Paracricetodon

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    We describe the remains of Aralocricetodon Bendukidze, 1993; Bagacricetodon Gomes Rodrigues et al., 2012; Eocricetodon Wang, 2007; Witenia de Bruijn et al., 2003 and Paracricetodon Schaub, 1925 (Cricetidae, Rodentia, Mammalia) from the Taatsiin Gol and Taatsiin Tsagaan Nuur areas (Mongolia). The studied material (comprising 128 teeth) stems from 9 localities and 23 fossil layers spanning a time interval from ∌33 to ∌24 Ma (early to late Oligocene) and covering the biozones from A to C1. The general dental pattern between the species from the early and late Oligocene differed. The occlusal pattern of the molars was more complicated and the crowns were lower during the early versus late Oligocene. This indicates a change in diet towards more abrasive plants. Several of the studied species were common in both Europe and Asia Minor during the early Oligocene. The species collected from the late Oligocene have also been recorded in Kazakhstan and China. This indicates an interesting biogeographical pattern that merits future study

    The record of Aplodontidae (Rodentia, Mammalia) in the Oligocene and Miocene of the Valley of Lakes (Central Mongolia) with some comments on the morphologic variability

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    The present publication reports new discoveries of Oligocene and early Miocene aplodontid rodents from the Taatsiin Gol area (Valley of Lakes) in Mongolia. The fossil aplodontids recovered in this area are mainly composed of dental remains, some fragmentary jaws plus one partially preserved skull. Aplodontid rodents have been found from the early Oligocene (local biozone A) to the early middle Miocene (local biozone D). Altogether, eight taxa belonging to five genera have been identified in the investigated deposits: Ninamys arboraptus, Ninamys kazimierzi, Promeniscomys cf. sinensis, Prosciurus? mongoliensis and Prosciurus? sp. nov. in the early Oligocene; N. arboraptus, Proansomys badamae sp. nov. and Ansomyinae indet. in the late Oligocene; and Ansomys sp.1 in the early Miocene. In addition, although outside of the topic of the present special issue, one additional taxon, Ansomys sp.2, is reported from the ?middle Miocene. The material of aplodontids is usually relatively scarce in Asian localities. For the first time, with a sample size of 81 specimens, the material from Central Mongolia (mainly from the Oligocene) now allows a more accurate description of the morphological and size variability and resolves some systematic problems. The study of these aplodontids reveals that they are more abundant and diverse in the early Oligocene and that the diversity decreases during the late Oligocene and Miocene. One hypothesis, to explain the opposite diversity trend observed previously for sciurids in the same region, is that both Sciuromorpha families might have competed for the same resources from the early Oligocene to the middle Miocene in Central Mongolia

    Aubenas-les-Alpes (S-E France). Part III – Last and final part of the mammalian assemblage with some comments on the palaeoenvironment and palaeobiogeography

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    L’étude du nouveau matĂ©riel issu d’Aubenas-les-Alpes permet de complĂ©ter la liste faunique par des taxa jusqu’alors inconnus dans cette localitĂ© (Neurogymnurus cayluxi, Issiodoromys minor, Eomys minor, Pseudocricetodon cf. hausi, Pseudocricetodon aff. philippi). Les nouveaux spĂ©cimens de la musaraigne Srinitium marteli amĂ©liorent notre connaissance de ce rare insectivore. Les caractĂ©ristiques du thĂ©ridomorphe I. minor confirment, de mĂȘme que l’ensemble de la faune de rongeurs, la corrĂ©lation avec le niveau MP25 (RupĂ©lien supĂ©rieur). L’assemblage d’Aubenas- les-Alpes indique un environnement plutĂŽt sec et ouvert, en accord avec le contexte climatique du dĂ©but de l’OligocĂšne, mais quelques diffĂ©rences sont Ă©galement notĂ©es par comparaison aux autres localitĂ©s du mĂȘme Ăąge. Finalement l’assemblage mammalien suggĂšre la mise en place d’une diffĂ©rentiation biogĂ©ographique Ă  l’échelle europĂ©enne au cours du RupĂ©lien supĂ©rieur.The study of the new material from Aubenas-les-Alpes makes it possible to add to the faunal list taxa hitherto unknown in this locality (Neurogymnurus cayluxi, Issiodoromys minor, Eomys minor, Pseudocricetodon cf. hausi, Pseudocricetodon aff. philippi). New specimens of the shrew Srinitium marteli increase our knowledge of this rare insectivore. The characteristics of the theridomorph I. minor confirm, as does the whole rodent fauna, the correlation with the MP25 level (Late Rupelian). The assemblage of Aubenas-les-Alpes indicates a rather open and dry environment, in accordance with the Early Oligocene climatic context, but some differences compared to other localities of the same age are also noticed. Finally the mammalian assemblage suggests an ongoing biogeographic differentiation at European scale during the Late Rupelian

    Les migrations dans la presse quotidienne en classe de QuatriĂšme

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    Le contenu enseignĂ© dans cette « Semaine de la presse » est celui du programme de gĂ©ographie du cycle 4 et de l'Ă©ducation morale et civique, adossĂ© Ă  des faits d'actualitĂ© rĂ©cente. Les compĂ©tences visĂ©es sont notamment liĂ©es Ă  la pĂ©dagogie de l'Ă©ducation aux mĂ©dias et Ă  l'information, Ă  la pĂ©dagogie de groupe et Ă  l'expression orale. L'intĂ©rĂȘt de cette expĂ©rience est d'ĂȘtre pluridisciplinaire. Il s'agissait autant de dĂ©velopper un regard gĂ©ographique sur les migrations que de saisir les migra..

    New data on Amynodontidae (Mammalia, Perissodactyla) from Eastern Europe: Phylogenetic and palaeobiogeographic implications around the Eocene-Oligocene transition

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    Amynodontidae is a family of Rhinocerotoidea (Mammalia, Perissodactyla) known from the late Early Eocene to the latest Oligocene, in North America and Eurasia. European Amynodontidae are very rare, and all remains belong almost exclusively to a single post—Grande Coupure genus from the Oligocene, Cadurcotherium. The “Grande Coupure” defines an extinctions and dispersal-generated originations event in Europe that is nearly contemporaneous with the Eocene-Oligocene transition. Perissodactyls are one of the major groups affected by this event: Palaeotheriidae went almost extinct during this crisis, whereas Rhinocerotidae appeared for the first time in Europe. Study of fossiliferous Eastern-European localities from this age is crucial for the understanding of this crisis. We report here three new localities of Amynodontidae in Eastern Europe. Two of them are dated from the Eocene (Morlaca, Romania; Dorog, Hungary), whereas the other is either Late Eocene or Early Oligocene (DobĂąrca, Romania). The skull from this latter locality belongs unexpectedly to the same individual as a previously described mandible attributed to “Cadurcodon” zimborensis. As a result, this specimen can be allocated to its proper locality, DobĂąrca, and is assigned to a new genus, Sellamynodon gen. nov. It is characterised by an extraordinary growth of the nuchal crest, a unique character among amynodontids. Along with this remarkable material from DobĂąrca, two specimens from another Romanian locality, Morlaca, have been recently discovered and are dated from the Late Eocene. They belong, as well as new material from Dorog (Middle Eocene, Hungary), to the genus Amynodontopsis, also found in North America. The new Hungarian material represents the earliest occurrence of Amynodontidae in Europe. New phylogenetic hypotheses of Rhinocerotoidea are proposed, including the new material presented here, and show that Amynodontidae may be closer to the polyphyletic family ÊœHyracodontidaeÊŒ than to Rhinocerotidae. Amynodontidae, with their deep preorbital fossa and extremely reduced premolars, display in fact a very derived condition, compared to rhinocerotids

    Early Agenian rhinocerotids from Wischberg (Canton Bern, Switzerland) and clarification of the systematics of the genus Diaceratherium

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    Background: Wischberg is a Swiss locality in Bern Canton which has yielded numerous vertebrates remains from the earliest Miocene (= MN1). It has a very rich faunal diversity, one of the richest in Switzerland for this age. Among all the mammals reported in the original faunal list 70 years ago, three rhinocerotid species were identified. The material consists of two fragmentary skulls, cranial fragments, several mandibles, teeth and postcranial bones, in a rather good state of preservation.Results: After reexamination of the material from this locality (curated in three different Swiss museums) and comparison with holotype specimens, we show that all rhinocerotid specimens from Wischberg can be referred to two species only. Most of the material can be attributed to the large-sized teleoceratine Diaceratherium lemanense, while only a few specimens, including a skull and mandible, belong to the much smaller sized Pleuroceros pleuroceros. We describe and illustrate for the first time most of these fossil remains. However, the systematics of the genus Diaceratherium is currently controversial, and based on our new observations we consider seven species as valid, though a large-scale phylogenetic study should be done in the future to resolve it. The rhinocerotid association found in Wischberg is nonetheless typical of the MN1 biozone, which results from a faunal renewal occurring just before the end of the Oligocene
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