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Comparative bone histology of rhabdodontid dinosaurs
Edina Prondvai
Keywords: bone histology-based ontogeny; Mochlodon; Rhabdodon; skeletal maturation; Zalmoxes

doi: 10.18563/pv.38.2.e1
 
  Abstract

    A comparative bone histological study of the three known genera of the endemic European ornithopod dinosaur family, Rhabdodontidae, is presented here in an ontogenetic context. Investigated specimens were assigned to different ontogenetic stages based exclusively on the histological indicators of osteologic maturation during diametrical bone growth; an entirely size-independent method as opposed to most previous studies. Qualitative comparison of bone histology of corresponding ontogenetic stages and elements among the three valid rhabdodontid genera, Mochlodon, Zalmoxes, and Rhabdodon, revealed some consistent patterns. Genus specific histological differences within Rhabdodontidae are most expressed between Rhabdodon and the Mochlodon-Zalmoxes clade. These indicate a prolonged phase of fast growth and a less constrained cyclicity in the growth dynamics of Rhabdodon, as opposed to the slower and more regulated growth strategy reflected in the bones of Mochlodon and Zalmoxes. These genus specific differences are consistent with the phylogenetic interrelation of the genera and are most probably related to the pronounced differences in body size. However, when compared to other ornithopods, most detected histological features in rhabdodontids do not seem to reliably reflect either phylogenetic relations or body size. A notable common feature of all rhabdodontid genera irrespective of body size is the ontogenetically early onset of cyclical growth and secondary remodelling; a pattern that more resembles the condition found in derived ornithopods than that described in more basal taxa which are closer relatives of rhabdodontids. The recognition of taxon-specific histological patterns as well as patterns indicative of ecological and thereby functional traits clearly requires more accurate, preferably quantitative evaluations.   


  Article infos

Published in Vol.38-2 (2014)

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Rongeurs muroidés du Néogène supérieur d'Afghanistan, évolution, biogéographie, corrélations
Louis D. Brandy
Keywords: Afghanistan; Muroidea; Neogene
 
  Abstract

    The rodent faunas of five afghan localities found in 1976 and 1977 (Sherullah, Ghazgay, Pul-e Charkhi, Dawrankhel 14 and 15) are studied.
    The rodents (Muridae, Cricetidae and Rhizomyidae) represent 8 genera and 10 species. The detailed description of the 2 new genera and 7 species diagnosed in 1979 is given. An other species is created : Pseudomeriones crapouilloti n. sp. These faunas precise the origin and diversification of Muridae and Cricetidae. A phyletic lineage known in Afghanistan is represented in East Africa by a ramus or a collateral lineage. The five localities are dated from Lower Turolian to Ruscinian. They constitute the frame of a chronologie scale for the Upper Continental Neogene of Afghanistan.
    The study of afghan material brings new data to the biogeography of Old Word's rodents during the Upper Neogene; from Pakistan to Europe and Africa, a rather warm and damp province would have existed till Upper Miocene; after which (in the mio-pliocene epoch) it would have divided into 3 parts, by aridification of the central area. 


  Article infos

Published in Vol. 11, Fasc. 4 (1981)

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Study of the Turolian hipparions of the lower Axios valley (Macedonia, Greece). 4. Localities of Dytiko.
George D. Koufos
Keywords: Equidae; Greece; Hipparion; Lower Axios Valley; Macedonia; Mammalia; Turolian
 
  Abstract

    The hipparions from the Dytiko localities of the lower Axios valley (Macedonia, Greece) are studied. The material comes from three localities Dytiko-l, 2, 3 (DTK, DIT, DKO), which are situated near the village of Dytiko, about 60 km northwest to Thessaloniki. Three species have been determined, the medium-sized H. mediterraneum, the small-sized H. matthewi and the very small-sized H. periafricanum. The determined Hipparion species, their morphological characters and their comparison with the other Axios valley material indicate a Late Turolian age for the Dytiko localities. 


  Article infos

Published in Vol. 18, Fasc. 4 (1988)

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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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The Pleistocene vertebrate fauna of Robinson Cave, Overton County, Tennessee
J. E. Guilday, H. W. Hamilton and A. D. Mc Crady
Keywords: Fauna; Mammalia; Pleistocene; Tennessee

doi: 10.18563/pv.2.2.25-75
 
  Abstract

    A late Pleistocene deposit of 60 species of vertebrates and 12 of invertebrates is described from Robinson Cave, Overton County, Tennessee, U.S.A. Forty-eight species of mammals are represented by at least 2,483 individuals; 10 % are extinct, 10 % occur in the state only as boreal relicts in the Great Smoky Mountains; 23 % no longer occur as far south as Tennessee; 57 % occur at or near the site today. Nínety-one percent of the Recent mammal species can be found living today in the Minnesota-Wisconsin area, approximately 10 degrees farther north. Fluorine analysis suggests a long period of accumulation. The following 10 mammalian species are recorded from Tennessee for the first time. Sorex arcticus, Microsorex hoyi, Citellus tridecemlineatus, Clethrionomys gapperi, Microtus pennsylvanicus, Synaptomys cooperi, Synaptomys borealis, Zapus nudsonius, Napaeozapus insignis, Martes americana. Six additional species are present as boreal relicts in the Great Smoky Mountains of eastern Tennessee but not at the site today : Sorex cinereus, Sorex dispar, Sorex palustris, Parascalops breweri, Glaucomys sabrinus, Mustela nivalis. Six forms are extinct: Canis dirus, Ursus americanus amplidens, Sangamona furtiva, Dasypus bellus, Mammut americanus,Megalonyx jeffersoni. Twenty-six additional species of mammals, all of the snails, birds, reptiles, and amphibians recovered from the fauna still inhabit the area today: The fauna is indicative of a cold-temperate climatic episode associated with the Wisconsin glaciation, but may be chronologically mixed. 


  Article infos

Published in Vol. 02, Fasc. 2 (1969)

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Pantolestidae nouveaux (Mammalia, Insectivora) de l'Eocène moyen de Bouxwiller (Alsace).
Jean-Jacques Jaeger
Keywords: Bouxwiller; Insectivora; Mammalia; Middle Eocene; Pantolestidae

doi: 10.18563/pv.3.3.63-82
 
  Abstract

    The Pantolestidae from the middle eocene of Bouxwiller are the subject of a detailed study. Buxolestes hammeli (n. g., n. sp.) is not closely related to any other European or North American form described until now; it presents, however, some characters in common with Pantolestes, a form of the same age from North America. A parallel evolution from a common ancestral form could explain this ressemblance.
    Another form (gen. and sp. indet.) accompanies Buxolertes hammeli in the Bouxwiller fauna.
      


  Article infos

Published in Vol. 03, Fasc. 3 (1970)

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Batoids (Rajiformes, Torpediniformes, Myliobatiformes) from the Sülstorf Beds (Chattian, Late Oligocene) of Mecklenburg, northeastern Germany: a revision and description of three new species
Thomas Reinecke
Keywords: Batoids; Chattian; Elasmobranchii; North Sea Basin; Oligocene

doi: 10.18563/pv.39.2.e2
 
  Abstract

    Bulk-sampling of fossil-rich tempestites from the Chattian Sülstorf Beds of
    Mecklenburg, north-eastern Germany, yielded a rich selachian fauna in which batoids
    predominate by the abundance of teeth but are subordinate by the number of taxa. Thirteen
    taxa are identified, among which rajiform batoids are the most diverse (six species). One
    genus and three species are newly described: Raja thiedei sp. nov., Oligoraja pristina gen. et
    sp. nov., and Torpedo chattica sp. nov. Two species are reallocated: Atlantoraja cecilae
    (Steurbaut & Herman, 1978) new comb., and Dipturus casieri (Steurbaut & Herman, 1978)
    new comb. Ontogenetic heterodonty is documented for the first time in the dental pattern of
    Myliobatis sp. Stratigraphical ranges of batoid taxa in the period from Rupelian to Langhian
    are presented and partly discussed in context with the palaeoclimatic evolution and
    palaeogeographic situation of the North Sea Basin. 


  Article infos

Published in Vol.39-2 (2015)

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Le genre Leptolophus (Perissodactyla, Mammalia): morphologie et histologie dentaires, anatomie cranienne, implications fonctionnelles.
Jean-Albert Remy
Keywords: dental histology; Eocene; functional anatomy; Palaeotheriidae; skull anatomy; Southern France; Systematics
 
  Abstract

    A strong lophodonty, an extreme heterodonty, some hypsodonty and regular overlayings of coronal cement are prominent features of the genus Leptolophus (Palaeotheriinae = Palaeotheriidae s.s.). The histological pattern of the teeth unusually joins type II enamel prisms, characteristic of advanced ungulates, together with archaic features, such as an almost complete lack of Hunter-Schreger zonation and a weak expanse of peritubular dentine. The skull is narrow and slender, with an elongated ante-orbital facial region, a moderately notched nasal aperture, a rather elongated post-canine diastem, parallel zygornatic arches and a fairly dorsally located squamoso-mandibular joint.The functional analysis brings to light "ectolophodont" masticatory cycles with two phases, in which maximum power was applied, contrary to equíds, on hindmost teeth; likewise, skull accomodations to increasing height of the teeth are quite different. This study leads to the assumption that Leptolophus may have been light mammals, living in rather open surroundings, browsing on herbaceous plants or leaves cropped close to the ground. Moreover, it appears that it could have been some inadequacy of dental structures to the dietary, which leaded to quick wear of the teeth and to many enamel notches, but had been somewhat balanced by the early increase of hypsodonty, not induced in such a case by a biotop deterioration (as it will happen at the end of the Eocene). This ínadaptation might account for the short duration of the genus Leptolophus, whose the 3 species, L. stehlini, L. nouletí and L. magnus n. sp. are indeed confined in the level MP 16. Its geographical spreading (as far as known, South of western Europe) and the morphological pattern of its dentition suggest that this genus would have been related to early upper Eocene endemic spanish forms.





      


  Article infos

Published in Vol. 27, Fasc. 1-2 (1998)

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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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Un nouveau genre de ?Palaeotheriidae (Perissodactyla, Mammalia) décelé dans les phosphorites du Quercy (Eocène supérieur ou Oligocène) d'après un arrière crâne sans dents.
Jean-Albert Remy
Keywords: endocranial cast; Epitympanic sinus; Palaeotheriidae; Paléogène; Quercy Phosphorites; skull anatomy
 
  Abstract

    A rear skull from the Quercy Phosphorites is described. It documents a new perissodactyl genus, likely assignable to the family Palaeotheriidae and probably paleogene of age. Owing to the lack of any tooth, this family assignment remains however somewhat hypothetical. The specimen is firstly characterised by the presence of a wide epitympanic sinus swelling and hollowing the squamosal shell and the post-glenoid process. This cavity might make up a peculiar pattern of improvement for the hearing apparatus by carrying out a kind of drum near the middle ear, whereas the bony tympanic remains barely bulged and forms but a few developed auditory bulla. This pattern appears an outcome of a trend observed with many palaeotheriids, such as Plagiolophus. Furthermore, the endocranial cast shows a rather high degree of gyrencephaly for a paleogene mammal. The prominent lambdoidal crest points out a powerful nape musculature and a lowered head bearing. Consequently, it is assumed that such an animal was probably living in somewhat open places, at the expense of rather tough vegetables. It might have been accordingly provided with a semi-hypsodont, cement covered, "plagiolophoid" dentition. 


  Article infos

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

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Les Amphibiens et les reptiles du Pliocène supérieur de Balaruc II (Herault, France)
Salvador Bailon
Keywords: amphibians; Europe; France; Pliocene; Reptiles
 
  Abstract

    The late Pliocene site (MN 16) of Balaruc II (Hérault, France) has provided remains of the following amphibians and reptiles: Chelotriton pliocenicus nov. sp. and Triturus marmoratus (Salamandridae), cf. Rana (Ranidae), cf. Blanus (Amphisbaenidae), cf. Agama (Agamidae),  Gekkonidae indet., Lacerta s.l. (Lacertidae), "Ophisaurus" sp. (Anguidae), Michauxophis occitanus (Aniliidae), Erycinae indet. (Boidae), Elaphe cf. E. longissima and Malpolon sp. (Colubridae), cf. Naja (Elapidae) and Vipera sp. (Viperidae). The salamandrid Chelotriton pliocenicus and the aniliid Michauxophis occitanus constitute, up to now, the only records of these groups in the European Pliocene. The fauna is indicative of a warm, dry
    subtropical climate. 


  Article infos

Published in Vol. 19, Fasc. 1 (1989)

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Sur les empreintes de pas des gros mammifères de l'Eocène supérieur de Garrigues-ste-Eulalie (Gard)
Paul Ellenberger
Keywords: Eocene; Euzet; Footprints; Ichnofauna
 
  Abstract

    Is hereby described an impressive lchnoiauna belonging to the Lower to Middle Ludian of the Gard (S. France). The slab, already cleaned over a length of 18 m, is located near the top of the Potamides aporoschema lacustrine limestone (Lower Ludian, Euzet zone). It is therefore older than the Célas sandstone deposit, and still more than the Melanoides albigensis and M. acutus marly limestone corresponding to the Upper Levels of the Ludian stage. Although biostratigraphically older than the La Débruge and Montmartre zone, the biotope shows already a sampling of very tall Artiodactyles, Perissodactyles and Carnivorous. One of the most « majestic ›› Artiodactyles, Anopolotheriipus lavocati, nov., points out a huge size type. To mention also among the Ichnotypes described, 10, the big Perissodactyle Palaeotheriipus similimedius, nov., and the big Carnivorous Hyaenodontipus praedator, nov. 


  Article infos

Published in Vol. 9, Ext (1980)

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Terrestrial vertebrate paleocommunities from the Cerro del Pueblo Formation (Late Cretaceous; Late Campanian) at Las Aguilas, Coahuila, Mexico
Héctor E. Rivera-Sylva, Eberhard Frey, Wolfgang . Stinnesbeck, Natalia Amezcua Torres and Diana Flores Huerta
Keywords: Campanian; Coahuila; dinosaurs; Mexico.; Vertebrates

doi: 10.18563/pv.42.2.e1
 
  Abstract

    The Las Águilas site near Porvenir de Jalpa, Coahuila, Mexico, is extremely rich in tetrapod remains comprising both bones and trackways of several dinosaur taxa of late Campanian age. Within a 50 m thick section we identified at least nine layers with dinosaur bone assemblages. In one of these the dinosaur bones are associated with remnants of eusuchian crocodilians, turtles, plesiosaurs, pterosaurs, tyrannosaurids, dromaeosaurids, parksosaurid, hadrosaurids, ceratopsids, and ankylosaurs. This layer is also rich in coprolites of turtles, crocodilians and likely theropods, thus providing evidence for the wealth of Late Cretaceous vertebrate life in the area. 


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Published in Vol 42-2 (2019)

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A new species of hippopotamine (Cetartiodactyla, Hippopotamidae) from the late Miocene Baynunah Formation, Abu Dhabi, United Arab Emirates
Jean-Renaud Boisserie, Mathieu Schuster, Mark J. Beech, Andrew Hill and Faysal Bibi
Keywords: Arab Peninsula; Hippopotamidae; Hippopotamine event; Systematics

doi: 10.18563/pv.41.1.e2
 
  Abstract

    The discovery of new hippopotamid material from the late Miocene Baynunah Formation (Abu Dhabi, United Arab Emirates) has prompted the revision of the existing material of this as yet unnamed fossil taxon. The Baynunah hippopotamid appears to be distinct from all other contemporary and later species in having a relatively more elongate symphysis, a feature similar to the earlier (and more primitive) Kenyapotamus. Yet, the Baynunah hippopotamid presents a dentition typical of the Hippopotaminae. It is therefore a distinct species attributed to the later subfamily, described and named in this contribution. This species provides further evidence for a ca. 8 Ma evolutionary event (termed “Hippopotamine Event”) that initiated the spread and ecological significance of the Hippopotaminae into wet habitats across Africa and Eurasia. The morphological affinities of the new species from Abu Dhabi suggest that the Arabian Peninsula was not a dispersal route from Africa toward southern Asia for the Hippopotamidae at ca. 7.5 Ma to 6.5 Ma. 


  Article infos

Published in Vol 41-1 (2018)

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S.I. Data
Révision systématique des Anchilophini (Palaeotheriidae, Perissodactyla, Mammalia).
Jean-Albert Remy
Keywords: Anchilophus; Eocene; new genus; new species; Palaeotheriidae; Paranchilophus; Perissodactyla; Systematics

doi: 10.18563/pv.37.1-3.1-165
 
  Abstract

    The knowledge of the Anchilophini has been lately renewed by the discovery of a rather large amount of new material still largely unpublished. This new material offers the opportunity of a systematic revision of this tribe gathering those of European Eocene Equoidea which bear no mesostyle on upper check teeth and display a heavy trend to the molarization of premolars.

    A cladistic analysis has made out two genera, Anchilophus (Paranchilophus included as a subgenus), characterized by a marked lophodonty and the transverse narrowness of the cheek teeth, a rather high hypsodonty, the frequent occurrence of "crochets" and "anticrochets" on the superior ones, and a rather weak molarization of the premolars, opposite to Metanchilophus n. gen. whose cheek teeth are more transversally elongated, less high, less lophodont, with cusps better distinct, enamel thicker and premolars more molarized on the whole.

    Three species of Anchilophus are recognized, A. desmaresti, type species of the genus, A. (Paranchilophus) remyi and A. (Paranchilophus) jeanteli n. sp.

    The genus Metanchilophus is more diversified with the species dumasi, radegondensis, gaudini (whose a new sub-species M. g. fontensis is defined), depereli, castrensis n. sp. and chaubeti n. sp.

    The skull anatomy has been moreover described with several taxa; it brings to light (for all that one can generalize) that Anchilophini were light animals with a slender and elongated snout, a thin zygomatic arch, a rather developed encephalon with an advanced gyrencephaly.

    The structure of the nasal opening together with the occurrence of epitympanic sinuses and the molarizing process of the premolars corroborate the attribution of this tribe to the family PalaeotheIiidae. 


  Article infos

Published in Vol. 37, Fasc. 1-3 (2012)

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Les nouvelles faunes de rongeurs proches de la limite mio-pliocène en Roussillon. Implications biostratigraphiques et biogéographiques
Jean-Pierre Aguilar, Jacques Michaux, Bernadette Bachelet, Marc Calvet and Jean-Pierre Faillat
Keywords: Arvicolidae; Cricetidae; Gliridae; Miocene; Muridae; Pliocene; Rodents; Southern France
 
  Abstract

    Three new fossiliferous localities, two of karstic origin, Castelnou 3 and Font Estramar, respectively Late Upper Miocene and Lower Pliocene, and one of lacustrine origin, Thuir, Lower Pliocene, add data about the transition between Miocene and Pliocene faunas of rodents in southern France. An unexpected association of taxa was present in the late Upper Miocene, including between others, Myocricetodon, Hispanomys, Ruscinomys, Cricetus barrierei, Promimomys and a new species of Stephanomys, S. dubari nov. sp. Myocricetodon is still known in the Lower Pliocene. It is shown that the large field-mice known since the Late Upper Miocene belong to two different lineages, on one side, A. jeanteti, on the other side, A. gudrunae followed by A. gorafensis. Biochronological and biogeographical implications are discussed. 


  Article infos

Published in Vol. 20, Fasc. 4 (1991)

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Critical comments on the genus Propachynolophus Lemoine, 1891 (Mammalia, Perissodactyla, Equoidea)
 
Jean-Albert Remy
Keywords: Eocene; Eurohippus; Pachynolophus; Propalaeotherium; tooth morphology

doi: 10.18563/pv.41.1.e3
 
  Abstract

    Abstract
     The validity of Propachynolophus Lemoine, 1891, supposedly an intermediate between Hyracotherium Owen, 1841 and Pachynolophus Pomel, 1847, has been questioned for a long time. A detailed analysis of features on which this genus is based further supported by a formal cladistic analysis demonstrates that Propachynolophus is not a valid taxon. The type species, “Propachynolophus gaudryi Lemoine, 1891” shall be assigned to Propalaeotherium Gervais, 1849, under the new combination Propalaeotherium gaudryi (Lemoine, 1891). “Pachynolophus maldani Lemoine, 1878”, later assigned to Propachynolophus, typifies the new genus Orolophus, under the binomen Orolophus maldani (Lemoine, 1878). The other referred species, “Propachynolophus levei Hooker, 1994” and “P. remyi Checa-Soler, 1997” are poorly documented, and both species shall be provisionally referred to as “Hyracotherium levei (Hooker, 1994) and “Hyracotherium remyi (Checa-Soler, 1997), pending new discoveries.
     
      


  Article infos

Published in Vol 41-1 (2018)

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S.I. Data
The skull of Tetraceratops insignis (Synapsida, Sphenacodontia)
Frederik Spindler
Keywords: cranium; pelycosaur; Permian; therapsid origins

doi: 10.18563/pv.43.1.e1
 
  Abstract

    Tetraceratops insignis is known from a single, crushed skull from the Lower Permian of Texas. Its unique proportions and osteological details gained central meaning in the question of the origins of Therapsida since this early synapsid has been determined as the oldest and less derived therapsid. Apart from Tetraceratops, the ‘mammal-like’ Therapsida and their sister, the pelycosaur-grade Sphenacodontidae, are separated by one of the longest ghost lineages in tetrapod fossil record. However, the minor, though well justified critique faced insistent publication regarding the therapsid hypothesis. A carefull re-evaluation of the holotypic skull reveals that therapsid traits cannot be supported, including a rejection of the formerly supposed adductor shelf in the temporal fenestra. Increased understanding of ‘pelycosaur’ character variation underlines a haptodontine-grade or, less likely, sphenacodontid position for Tetraceratops


  Article infos

Published in Vol 43-1 (2020)

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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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Les Palaeotheridae (Perissodactyla) de la faune de Mammifères de Fons 1 (Eocène supérieur).
Jean-Albert Remy
Keywords: Anchilophus; Eocene; Pachynolophus; Palaeotheriidae; Perissodactyla

doi: 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. 


  Article infos

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

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