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Page 11 of 18, showing 20 record(s) out of 359 total

Neolicaphrium recens Frenguelli,1921,the only surviving proterotheriidae (Litopterna, Mammalia) into the south american Pleistocene.
Mariano Bond, Daniel Perea, Martin Ubilla and Adan Tauber
Published online: 7/30/01

Keywords: Litopterna; Neolicaphrium recens; Pleistocene; Proterotheriidae; South America

  Abstract

    The litoptem Proterotheriidae are extinct endemic South American ungulates frequently used as an example of evolutionary convergence with the horses. They were considered to be exclusively Tertiary representatives with the youngest record being in the late Pliocene, before the appearence of the equids and cervids during the Great American Interchange. Two undoubted Pleistocene records in Argentina and the specimen here described from Uruguay, confirm the persistence of the proterotherids into that period. In the Quaternary, these ungulates are found outside the typical pampean region and probably were confined to a few northern and warmer more forested relictual microhabitats.

      


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Published in Vol. 30, Fasc. 1-2 (2001)

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Systematic revision of Ctenodactylidae (Mammalia, Rodentia) from theMiocene of Pakistan.
J.A. Baskin
Published online: 3/18/96

Keywords: Ctenodactylidae; Miocene; Prosayimys; Rodents; Sayimys; Siwalik

  Abstract

    Extensive sampling of the Siwalik deposits of the Potwar Plateau of northem Pakistan and from the Zinda Pir dome of central Pakistan has produced a fossil record of Miocene ctenodactylids that can be correlated with the paleomagnetic time scale. The early Miocene Prosayimys flynni (n. gen., n. sp.) is recognized as the first ctenodactylid in the Indian subcontinent. Prosayimys is ancestral to Sayimys. From the late early Miocene to the early late Miocene, there is an anagenetic succession of three species of Sayimys: S. cf. S. intermedius, S. sivalensis, and S. chinjiensis (n. sp.). Sayimys chinjiensis gave rise to the late late Miocene S. perplexus. A second lineage is represented by Sayimys minor, S. sp. A, and S. sp. B. 


  PV article infos

Published in Vol. 25, Fasc. 1 (1996)

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Revision of the family Cephalomyidae (Rodentia, Caviomorpha) and new cephalomyids from the early Miocene of Patagonia.
Alejandro Kramarz
Published online: 7/30/01

Keywords: Cephalomyidae; Lower Miocene; Patagonia; Rodentia; Soriamys; Systematics

  Abstract

     A new genus of hystricognath rodent with two new species, Soriamys gaimanensis and Soriamys ganganensis, from the Colhuehuapian Age (Early Miocene), Sarmiento Formation, of Patagonia is described. The first species comes from the south barranca of the valley of Rio Chubut, near Gaiman locality (Chubut Province). It is known through a great number of dental remains in different stages of wear. The teeth are protohypsodont, with cement in the principal valleys. P4 are simpler, more oval inoutline and without a differentiated hypocone-hypoflexus. Upper molars are pentalophodont in early stages of wear and become bilobated in middle and advanced stages; M3 have a temporary third posterior lobe due to the maintenance of the braquiflexus on the posterior wall of the tooth. Lower teeth have a completely asymrnetrical pattern in relation to the uppers. The molars are trilophodont, with only one complex crest in the trigonid composed of the fusion of the anterolophid and mesolophid. The dp4 have a derived pentalophodont pattern due to the loss or fusion of the mesolophid and the development of an accessory transverse crest between the anterolophid and metalophid. The second species is known through a complete skull and jaw and other skull fragments with the dentition, proceeding from Pampa de Gan Gan, Chubut province. Respect to the first species, the teeth are higher crowned, with an earlier occlusal simplification and a third posterior lobe of M3 more developed and persistent. The skull and jaws show many chinchilloid characters, such as jugal bone with an ascending process, concave palate, very prominent dorsal shelf of the masseteric fossa, nasolachrymal duct opened laterally on the maxillary and very developed lateral mandibular fossa. Moreover, Soriamys is closely related to Cephalomys by sharing a similar asymmetric dental pattern and other dental and mandibular characters. These two genera constitute a natural group, the Cephalomyidae, with peculiar dental characters, like the asymmetric pattem of the upper and lower teeth; Cephalomyopsis, and probably Litadontomys, can be considered part of this group. Scotamys and Perimys constitute a distinct lineage (the Neopiblemidae or Perimyidae), more closely related to the chinchillids. Many characters shared by cephalomyids, eocardiids and caviids suggest a closer affinity between the Chinchilloidea and the Cavioiidea as a whole. Abrocoma shows also an asymmetric dental pattern and other chinchilloid features that suggest some degree of relationship with the cephalomyids, still not well determined. 


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Published in Vol. 30, Fasc. 1-2 (2001)

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Rongeurs du Miocène supérieur de Chorora, Ethiopie: Murinae, Dendromurinae et conclusions.
Denis Geraads
Published online: 7/30/01

Keywords: Ethiopia; Late Miocene; Muridae; Rodentia

  Abstract

    The subfamilies Murinae and "Dendromurinae" both include 4 species at Chorora. Among the former, while Preacomys nov. gen. seems to be a forerunner of Acomys, the affinities of the remaining, poorly known taxa, are more difficult to evaluate. The bulk of the fauna, remarkably, consists of Dendromurines. Their similarities with those of Ngorora tends to pull the site back in time, but the large size and diversity of Murines fit better an age more recent than the very beginning of the Late Miocene.

      


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Published in Vol. 30, Fasc. 1-2 (2001)

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Fossil snakes from the Palaeocene of Sao José de Itaborai, Brazil, Part II. Boidae
Jean-Claude Rage
Published online: 12/28/01

Keywords: Boidae; Boinae; Brazil; Erycinae; New taxa; Palaeocene; Snakes

  Abstract

    The middle Palaeocene of São José de ltaboraí (State of Rio de Janeiro, Brazil) has produced a rich and diverse fauna of boid snakes. It comprises six or seven species: Hechtophis austrinus gen. et sp. nov., Corallus priscus sp. nov., Waincophís pressulus sp. nov., Waincophis cameratus sp. nov.,"Boinae A", and "Boinae B". Moreover, two dentaries might pertain to either H. austrinus or "Boinae B", or even represent a distinct taxon. Hechtophis austrinus is assigned, with reservation, to the Erycinae. All other taxa are referred to the Boinae. The vertebrae of all taxa have paracotylar foramina, which raises the problem of the apomorphic or plesiomorphic nature of this feature. This fauna also raises the question of the presence of extinct erycine boids in South America, but it does not allow this question to be settled. 


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Published in Vol. 30, Fasc. 3-4 (2001)

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The Gliridae (Mammalia) from the oligocene (MP24) of Gröben 3 in the folded molasse of southern Germany
Undine Uhlig
Published online: 12/28/01

Keywords: Biostratigraphy; Cyrena Beds; folded molasse; Germany; Gliridae; level MP 24; Mammals; Oligocene; Palaeoecology

  Abstract

    This study describes four taxa of Gliridae from the Oligocene mammal locality Gröben 3: Gliravus tenuis BAI-ILO, 1975, Bransatoglis micio (MISONNE, 1957), B. planus (BAHLO, 1975) and B. heissigi n. sp. Gliravus tenuis from Gröben 3 is somewhat more advanced than the type population found in Heimersheim. This confirms previous research suggesting that Gröben 3 should be dated earlier than Heimersheim (MP 24). The first documented occurrence of B. mício around level MP 24 was found in Gröben 3. An abundance of tooth material from B. planus in Gröben 3 makes it possible, for the first time, to observe evolutionary stages within this species from MP 21 until MP 28. B. heissigi n. sp. is restricted to level MP 24. This species is located between B. mísonnei (MP 20 - 23) and Microdyromys praemurinus (MP 25 - 28). Within the lineage Bransatoglis bahloi - B. misonnei - B. heissigi, a decrease in size is noticeable.

      


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Published in Vol. 30, Fasc. 3-4 (2001)

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The endocranial cast and encephalization quotient of Ptilodus (Multituberculata, Mammalia)
David W. Krause and Zofia Kielan-Jaworowska
Published online: 2/11/93

Keywords: encephaIization quotient; endocranial cast; Montana; Multituberculata; olfactory bulbs; Paleocene; Ptilodus

  Abstract

    Simpson (1937a) reconstructed the brain of the Paleocene multituberculate Ptilodus as having the olfactory bulbs widest anteriorly, an unusual condition among mammals. Slight preparation and reexamination of the endocast specimens of Ptilodus reveals that the olfactory bulbs in fact taper anteriorly, as in the recently-described endocranial casts of three multituberculate species from the Late Cretaceous of Asia, and as in those of other mammals. The brain of Ptilodus was therefore essentially of the same general pattem as in other multituberculates. Ptilodus differs, however, in having the vermis more deeply inserted between the cerebral hemispheres. Other details concerning the endocast morphology of Ptilodus are clarified.

    The encephalization quotient (EQ) of Ptilodus is recalculated from revised estimates of both endocranial volume and body mass to fall somewhere within a broad range of values; from 0.41 to 0.62 if the olfactory bulbs are included and from 0.37 to 0.55 if they are not. In any case, the relative brain size of Ptilodus is roughly equivalent to that of Chulsanbaatar, the only other multituberculate for which EQ has been calculated, but considerably smaller than that of an average extant mammnal. 


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

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Nouveaux gisements à rongeurs dans les molasses oligo-miocènes de la région toulousaine
Francis Duranthon
Published online: 2/11/93

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

  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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Mammoths, mastodonts & elephants. biology, behavior and the fossil record

Gary HAYNES, 1992. Cambridge University Press, New York, xii + 413 p., ISBN 0-521-38435-4
Jean-Loup Welcomme
Published online: 2/11/93

Keywords: Elephants; Mammoths; Mastodonts

  Abstract

    L'ouvrage est divisé en trois grandes parties traitant successivement: I. l'anatomie ("Proboscidean flesh and bones"), en abordant la taxonomie, l'allure générale et l'éco-éthologie des proboscidiens actuels et fossiles; II. les causes de mortalité collective naturelle et provoquée chez les actuels; III. les documents fossiles et l'extinction des formes anciennes d'Amérique du Nord. 


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

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Koobi Fora Research Project, volume 3. The fossil ungulates: geology, fossil artiodactyls, and palaeoenvironments, édité par John Michael HARRIS, 1991. Clarendon Press, Oxford, xvi + 384 p. ISBN 0-19-857399-5.
Jean Sudre
Published online: 2/11/93

Keywords: Artiodactyls; palaeovenvironments; Ungulates

  Abstract

    Avec ce volume se clôture l'étude géologique et paléontologique des sites à hominidés de Koobi Fora. Il fait suite aux deux précédents ouvrages, parus respectivement en 1978 et 1983, consacrés également à l'étude des faunes recueillies sur ces gisements dans le cadre du Koobi Fora Research Project. 


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

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Les traces de pas de Dinosaures et autres Archosaures du Lias inférieur des grands Causses, Sud de la France
Georges Demathieu, Georges Gand, Jacques Sciau, Pierre Freytet and Jacques Garric
Published online: 12/15/02

Keywords: Dinosauroid footprints; France; Grands-Causses; Hettangian; ichnostratigraphy; paleoenvironments; Sinemurian; statistical results

https://doi.org/10.18563/pv.31.1-4.1-143

  Abstract

    The Causses" is a near 3400 km2 large plateau located in the south of France. Here the first dinosaur footprints where found in 1935. After this, this area has yielded an ever-increasing number of ichnites now in excess of 500 specimens. These latter, 15 to 50 cm long, tridactyl or tetradactyl footprints of generally biped animals, were discovered at the surface of Hettangian to lower Sinemurian dolomite layers within 4 distinct stratigraphic units. The 35 sites bearing ichnites are located on the plateau margin. For the first time, morphologic characters studied through descriptive statistic methods with the usual parameters and classical Student and Snédecor tests, allowed us, to divide the whole set of biped traces into 6 ichnospecies. Their definitions are further constrained by multivariate statistical results using Principal Component Analysis (PCA), Factor Analysis of correspondances (FAC) and Discriminant Analysis (DA). All have confirmed the morphologic observations. So that now, the following taxa are identified : Grallator variabilis, G. lescurei, G. sauclierensis, G. minusculus, Eubrontes giganteus, Dilophosauripus williamsi, cf. Moraesichnium, Orníthopus fabrei nov ichnosp. The more immediately visible differences relate to the interdigital II-IV divarication and the digit length ratio. To this panel, we must add Batrachopus deweyi and shapes suggesting Trisauropodichnus and/or Anomoepus. Among all ichnite associations described in the lower Liasic, the New England assemblage presents the most affinities with ours. It shows the ichnotaxa Grallator, Dilophosauripus, Eubrontes, Batrachopus without forgetting Ornithopus fabrei nov. ichnosp. which is close to Ornithopus gallinaceus from the Massachusetts and Connecticut basins. On comparing the present early Jurassic ichnofauna of the Causses with the ones of the Middle and Upper Triassic formations of the eastem border of the Massif Central (France), it appears that tridactyl footprints become more and more numerous and large from Triassic to Early Jurassic. In the Causses, these latest are prevalent but in Quercy (France), Poland, Italy, USA, they are also associated with Omithopoda, Thyreophora and Sauropoda ichnites. Footprint areas considered here were generaly under an arid climate. Animals that passed by were heavy and bulky possible Megalosaur trackmakers, and lighter and slender Coelophysids or Ceratosaurs. For all, these areas were pathways as the orientations of the trackways seem point out. The directions followed by these reptiles were without any important variation during the Hettango-Sinemurian stages. These areas were also used from time to time by Crocodilomorpha and may be tetradactyl (I-IV) bipedal avian Theropods. However, the number of such trackways in sites, sometimes substantial, should not lead us to overestimate the trackmakers populations. These last were probably relatively moderately abondant in this inter-supratidal swamp environment. In the Causses, ichnites are connected with former algo-laminated deposits (Algal mats) which were rapidly hardened by means of calcitisation of cyanobacteria. The result has been a moderate depth of footprints; autopodia disturbing only a few cm of the carbonate substrate. Other fossils have been discovered : invertebrates with thin bivalve and gastropod shells, crustaceans tests and plants. These latter suggest the existence of paleomangroves like environments but also continental vegetation periodically overruning the swamp environment during regression/transgression cycles. At these times, wooded parts of it, could become protecting, feeding, resting and nesting places.

      


  PV article infos

Published in Vol. 31, Fasc. 1-4 (2002)

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Lower Paleogene crocodilians from Silveirinha, Portugal.
Miguel T. Antunes
Published online: 10/15/03

Keywords: ?Upper Paleocene / Lowermost Eocene; Crocodilians; Ecology; Portugal

  Abstract

    The presence at Silveirinha of one of the earliest, ? Late Paleocene or Lowermost Eocene, european representatives of the genus Diplocynodon is based mostly on isolated bones and teeth (often from juveniles). This small-sized form is the only crocodilian so far recognized in this site. The longevity of Diplocynodon in Portugal becomes much extended; the genus survived there until the Middle Miocene at least. A discussion on the possible affinities with other eocene Díplocynodon and especially those from Cubillos-Valdegallina (Zamora, Spain) is presented. On the other hand, differences have been detected in comparison with: Díplocynodon tormis, from the middle Eocene of the Douro basin in Spain, which may belong to another phyletic line; and the aff. Diplocynodon from Dormaal (Belgium) and Le Quesnoy (France), nearly contemporaneous of Silveirinha. The Silveirinha Diplocynodon and many other data strongly suggest moist, subtropical, quite limited in space environments related to an alluvial plain crossed by small, meandering channels. 


  PV article infos

Published in Vol. 32, Fasc. 1 (2003)

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Diversity of triconodont mammals from the early Cretaceous of North Africa-affinities of the Amphilestids
Denise Sigogneau-Russell
Published online: 10/15/03

Keywords: amphilestines; Early Cretaceous; gobiconodontines; North Africa; Teeth; triconodonts

  Abstract

    The mammalian fauna (represented only by isolated teeth) from the early Cretaceous of Morocco includes a number of non-'therian' specimens, characterized by the antero-posterior alignement of the main molar cusps. This assemblage is very heterogenous, including forms (among them Gobiconodon palaios sp. nov.) that can be related to Laurasian triconodonts and several forms so far known only in this part of Gondwana (among them Kryptotherium polysphenos gen. et sp. nov.). The latter, in particular, exemplifies the diversity of the mammalian dental morphology in the Mesozoic, often largely underestimated. In the last part of this paper, the 'therian' affinity of the 'amphilestids' is discussed, on the basis of the arrangement of molar cusps, the interlocking mechanism and the occlusal pattem. 


  PV article infos

Published in Vol. 32, Fasc. 1 (2003)

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Analyse d'ouvrage: “A.G. SMITH, D.G. SMITH & B.M. FUNNELL: Atlas of Mesozoic and Cenozoic coastlines (1995)”
Jacques Michaux
Published online: 3/18/96

Keywords: Atlas; Book review; Cenozoic; Coastlines; Mesozoic

  Abstract

    ATLAS OF MESOZOIC AND CENOZOIC COASTLINES, par Alan G. SMITH, David G. SMITH & Brian M. FUNNELL, 1995. Cambridge University Press, 99 p., 31 cartes, 3 tab!., 2 fig. ISBN 0-521-45155-8.

    L' "Atlas of Mesozoic and Cenozoic coastlines" succède avec bonheur aux "Mesozoic and Cenozoic paleocontinental maps" de Smith & Briden, publié en 1977. 


  PV article infos

Published in Vol. 25, Fasc. 1 (1996)

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Analyse d'ouvrage: “J.J. THOMASON (Ed.): Functional morphology invertebrate paleontology (1995)”
Jacques Michaux
Published online: 3/18/96

Keywords: Book review; Functional morphology

  Abstract

    Functional morphology invertebrate paleontology, édité par Jeffrey J. THOMASON, 1995. Cambridge University Press, xi + 277 p. ISBN 0-521-44095-5, f. 45,00 ($ 69,95).

    La morphologie fonctionnelle appliquée aux fossiles demeure un sujet à la fois passionnant et important. Passionnant, car elle s'adresse à des êtres disparus, aux combinaisons de caractères parfois inattendues et sans contrepartie chez les formes actuelles. Sujet important, car il faut, au delà de la constatation classique de l'adéquation de la forme des organes à leur fonction, expliquer l'origine des structures par évolution. L'évolution ou descendance avec modification, implique que les êtres vivants sont reliés les uns aux autres et qu'i! est possible de tenter à l'aide d'un raisonnement par inférence, la caractérisation des ancêtres en fonction des traits des formes auxquelles ils ont donné naissance. Mais il faut ajouter que par sa fonction, la structure relie immédiatement l'animal à son milieu puisqu'elle assure un rôle biologique. 


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Published in Vol. 25, Fasc. 1 (1996)

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First record of dinosaur eggshells and teeth from the north-west african Maastrichtian (Morocco).
Géraldine Garcia, Rodolphe Tabuce, Henri Cappetta, Bernard Marandat, Ilhem Bentaleb, Aziza Benabdallah and Monique Vianey-Liaud
Published online: 12/15/03

Keywords: Africa; amniotic eggshells; Maastrichtian; Morocco; theropod teeth

  Abstract

    We report the discovery of amniotic eggshells and theropod teeth from the Late Cretaccous  period in Morocco.The megaloolithid family represents the only known dinosaur egg remains in the north part of Africa and attests indirectly to the occurrence of sauropod dinosaurs (titanosaurids) in the Maastrichtian of Africa.

      


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

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La région des phosphorites du Quercy
A. Cavaillé
Published online: 11/15/74

Keywords: Quercy Phosphorites

  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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Les rongeurs de l'Oligocène inférieur d'Escamps
Monique Vianey-Liaud
Published online: 12/1/74

Keywords: Escamps; Quercy Phosphorites; Rodents; Theridomyidae

  Abstract

    La faune de Rongeurs d'Escamps (Lot) bien que relativement pauvre en espèces (dix) s'avère riche d'enseignement pour les Rongeurs de l'Oligocène inférieur d'Europe Occidentale. Cette periode semble caracterisée par une cladogenèse des Théridomyines. A Escamps, un nouveau genre (Patriotheridomys) est décrit ainsi qu'une nouvelle espèce de Theridomys. Avec Oltmamys platyceps, décrit ici plus complètement et désormais bien situé stratigraphiquement, les deux espèces précédentes constituent un ensemble original du Sud de la France. A la même époque, en Angleterre, Allemagne et Espagne, des espèces «régionales» de Théridomyinés se dersifient.  A côté de ces formes qui ne semblent pas franchir la «Grande Coupure» sont représentées deux lignées d'Issiodoromyinés (Elfomys sp et Pseudoltmomys cuvieri), une de Théridomyiné (T. (Blainvillimys) rotundidens) ainsi qu'un Gliridé, Gliravus priscus (que l'on différencie nettement de la deuxième lignée des Gliravus oligocènes : G.  meridionalis -> G. majori). On retrouve ces formes dans les gisements plus récents du niveau de Hoogbutsel où elles sont à peine plus évoluées. Le fait que les degrés évolutifs de ces lignées soient très proches laisse supposer que le laps de temps séparant les niveaux d'Ecamps et Hoogbutsel fut relativement court. 


  PV article infos

Published in Vol. 06, Fasc. 3-4 (1975)

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Contribution à l'étude des Cricétidés oligocènes d'Europe occidentale
Monique Vianey-Liaud
Published online: 1/20/72

Keywords: Cricetidae; Europe; Oligocene

https://doi.org/10.18563/pv.5.1.1-44

  Abstract

    Of the ten cricetid species from the Oligocene of Western Europe, attributed until now to the genus Eucricetodon, only four prove to be utilizable - E. atavus, E. huberi, E. praecursor, E. collatum - to which it is possible to add two forms newly described: E. huerzeleri and E. quercyi. The evolullon of the genus Pseudocricetodon is also the subject of new observations. The study of the dental morphology allows us to distinguish in these two genera three lineages beginning in the middle Oligocene:

    - Lineage P. montalbenensis-P. thaleri (from Montalban to Goderet), of small size, without
    increase in size.
    - LineageE. atavus-E. infralactorensis (from Hoogbulsel to Estrepouy), of middle size, with a regular increase in size.
    - Lineage E. huerzeleri-E. haslachense (level of Montalban to that of Estrepouy), of large size, with an increase in size.

    Two other forms are equally represented in these loealitles: Heterocricetodon aff. helbengi and Melissiodon quercyi. It has been possible to attribute a precise age (zone of "Cournon") to the last species, which has been defined by Schaub (l925) from material in the Old Quercy collections. The genera Pseudocricetodon, Eucricetodon, ? "Cricetodon", Leydimys, Eumys, differentiated at the beginning of the middle Oligocene in Europe, Asia and North America, seem to derive from a common ancestral group. The place of origin of this group could be situated in Asia. 


  PV article infos

Published in Vol. 05, Fasc. 1 (1972)

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Etude du crâne de Pachynolophus lavocati n. sp. (Perissodactyla, Palaeotheriidae) des Phosphorites du Quercy
Jean-Albert Remy
Published online: 2/15/72

Keywords: Perissodactyla; Quercy Phosphorites

https://doi.org/10.18563/pv.5.2.45-78

  Abstract

    The genus Pachynolophus, one of the poorest known of the Palaeotheriidae, includes the brachyodont forms with reduced and non-molariform premolars and with upper molars lacking a mesostyle. Quantitative characters (divers surface indications and elongation of the teeth), while demonstrating a close relationship to Hyracotherium, permit a better differentiation of the genus, confirm its specific splitting, and permit the distinction of three lineages. The skull from Memerlein is taken as the type of a new species, P. Iavocati, of which the dentition is extremely characterized by its lophiodonty, the strong reduction of the premolars and the reduction of the cingula. This characterization testifies to a late age which extends the existence of the genus quite near to the Eocene-Oligocene limit. Compared with the only two skulls known of related species (Hyracotheríum vulpiceps and Pachynolophus Iivinierensis), that from Memerlein is distinguished by progressive characters affecting diferent regions but most particularly the braincase; it is not possible, however, to isolate within this evolution the part which leads to a systematic differentiation. Modernization is translated by a considerable increase in size of the braincase, principally in the frontal region, a development of the facial region with anterior displacement of the dental series and a greater specialization of the masticatory apparatus. This evolution parallels the history of the Equidae of the North American early Tertiary, but certain particularities, the form of the alisphenoid, the presence of an anterior frontal foramen, and the structure of the paroccipital apophysis, testifies to the independance of the European forms. 


  PV article infos

Published in Vol. 05, Fasc. 2 (1972)

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Page 11 of 18, showing 20 record(s) out of 359 total