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Page 11 of 19, showing 20 record(s) out of 366 total

Premières données sur les rongeurs de la formation de Ch'orora (Ethiopie) d'âge Miocène supérieur. I: Thryonomyidés
Jean-Jacques Jaeger Logo, Jacques Michaux and Maurice Sabatier
Published online: 01/10/1980

Keywords: Ethiopia; Paraulacodus; Rodents; Upper Miocene

https://doi.org/10.18563/pv.9.ext.365-374

  Abstract

    The genus Paraulacodus has been collected in the Ch'orora formation of Upper Miocene age, in Ethiopia. The new species, P. johanesi n. sp.. is more evolved than the previously described indian species P. indicus HINTON of the Siwalik Hills area. The morphological gap between P. johanesi and the present Thryonomys is still important. 


  PV article infos

Published in Vol. 9, Ext (1980)

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Nouvelle interprétation de l'évolution du genre Megacricetodon au cours du Miocène
Jean-Pierre Aguilar
Published online: 01/10/1980

Keywords: Megacricetodon; Micromammals; Miocene

https://doi.org/10.18563/pv.9.ext.355-364

  Abstract

    La découverte de nouveaux gisements à micromammifères dans le Miocène du Sud de la France et d'Espagne montre que, s'il n'est plus possible d'accepter dans son intégralité le schéma phylétique de Fahlbusch du genre Megacricetodon, il existe toutefois des segments de lignées à l'intérieur de provinces géographiques différentes (Péninsule Ibérique, France, Europe Centrale), avec lesquels on peut établir une biochronologie locale, segments qu'il est aussi possible de placer les uns par rapport aux autres, en utilisant les corrélations que l'on peut reconnaître entre certains niveaux repères des mammalogistes et l'échelle stratigraphique marine.
    En utilisant ces données nouvelles, et d'après l'étude de la première molaire inférieure, nous proposons le
    schéma évolutif suivant, pour les espèces de grande taille :

    1 - au début du Burdigalien supérieur. une espèce commune, M. collongensis, issue de la forme ancestrale M. primitivus, est présente, de la Péninsule Ibérique à l'Europe Centrale. Son évolution est mal connue en Espagne, par contre cette lignée s'éteindrait en France au Burdigalien terminal avec le stade M. gersii nov. sp. de Sansan et de Luc-sur-Orbieu.
    2 - au cours de la régression post-burdigalienne. reconnue en Languedoc et dans la Péninsule Ibérique apparaîtrait une espèce immigrante, M. crusafonti qui, dans cette dernière province, évolue pour donner M. ibericus de Nombrevilla. L'espèce M. gregarius de La Grive M et de La Grenatière dériverait de cette forme immigrants, en ayant une évolution différente.
    3 - en Suisse, Bavière et Europe centrale, la lignée M. primitivus - M. collongensis va s'individualiser, dès le Burdigalien supérieur ou terminal, et donner naissance à la lignée M. bavaricus qui s'éteindra avec le stade M. germanicus nov. sp. du gisement anté - Hipparion de Anwil. Cette dernière espèce a été trouvée pour la première fois en France, dans le gisement de Collet Redon. 


  PV article infos

Published in Vol. 9, Ext (1980)

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On the genus Dikkomys (Geomyoidea, Mammalia)
Morton Green and Philip R. Bjork
Published online: 01/10/1980

Keywords: Dikkomys; Geomyoidae; North America

https://doi.org/10.18563/pv.9.ext.343-353

  Abstract

    The geomyoid genus Dikkomys is well represented in a sample from the Black Bear Quarry Il local fauna of Early Hemingfordian age in Bennett County, South Dakota. Isolated unworn P/4's of Dikkomys matthewi WOOD have a prominent median cristid (sagicristid) with a connection to the metaconid and the hypolophid. With wear, P/4 does not become as molariform as P/4 because of this cristid.
    A large sample of the Whitneyan beteromyid Proheteromys nebraskensis WOOD contains variants of the P/4 with on incipient sagicristid in approximately 18 percent of the population. The upper dentition and lower molars of Proheteromys nebraskensis are sufficiently generalized to indicate probable ancestry to Dikkomys


  PV article infos

Published in Vol. 9, Ext (1980)

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Pronycticebus neglectus - an almost complete adapid primate specimen from the Geiseltal (GDR)
Urs Thalmann, Hartmut Haubold and Robert D. Martin
Published online: 04/12/1989

Keywords: Adapiformes; Eocene; Paleoecology; PHYLOGENY; Pronycticebus neglectus

https://doi.org/10.18563/pv.19.3.115-130

  Abstract

    In the course of the current revision of adapid primates from the Eocene Geiseltal, an almost complete specimen was found in the Geiseltal Museum collections. The fossil, the most complete adapid specimen so far discovered in Europe, has been determined as Pronycticebus neglectus n. sp.
    Ecology and locomotion as well as the likely phylogenetic position within the infraorder Adapiformes are discussed. 


  PV article infos

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

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Cricetid and arvicolid rodents of the California wash local fauna, late Blancan of the san Pedro Valley, Arizona.
Cristiana Mezzabotta
Published online: 15/12/1997

Keywords: Arvicolidae; Blancan; Cenozoic; Cricetidae; Mammals

https://doi.org/10.18563/pv.26.1-4.189-218

  Abstract

    An assemblage of micromammals is reported from California Wash, a fossil bearing continental deposit in the San Pedro Valley, Arizona, late Blancan in age. Cricetid and Arvicolid rodents are richly represented, including four and two species, respectively. This study mainly focuses on Sígmodon, the most abundant form. The sample of Sigmodon is compared to samples of the same genus from other localities of the San Pedro Valley of comparable age, and some inferences on the taxonomy of the genus are attempted. The specimens are referred to Sigmodon minor and Sigmodon cf. S. curtisi. Other cricetids (Onychomys pedroensis and Baiomys brachygnathus) and arvicolids (Mictomys vetus and Ondatra ídahoensis) are also recognized and described. 


  PV article infos

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

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Evolution de la lignée Megacricetodon collongensis-Megacricetotodon roussillonensis (Cricetidae, Rodentia, mammalia) au cours du Midocène inférieur et moyen dans le Sud de la France.
Jean-Pierre Aguilar
Published online: 14/06/1995

Keywords: Cricetids rodents; Evolutionary lineage; Lower and Middle Miocene; Mammalian biochronology; Megacricetodon new species; Southern France

https://doi.org/10.18563/pv.24.1-2.1-45

  Abstract

    New populations of the genus Megacricetodon have recently been discovered in Southern France.Two new species are defined: M. lemartineli n. sp. and M. fournasi n. sp., their stages of evolution are intermediate between those of M. gersii and M. roussillonensis. Morphological and biometrical analysis indicate the presence of only one lineage: M. collongensis--M. collongensis-gersii--M. gersii--M.lemartineli nov. sp.--M. fournasi nov. sp. and M. roussillonensis. This observation allows to refine the chronology based on rodents, for the Late Early Miocene and the Middle Miocene in the Southern France.
    Comparisons with some iberian species are done. The validity of the French species M. bezianensis and M. bourgeoisi is discussed. 


  PV article infos

Published in Vol. 24, Fasc. 1-2 (1995)

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Présence de Palaeobatrachidae (Anura) dans des gisements tertiaires Français caractérisation, distribution et affinités de la famille
Colette Vergnaud-Grazzini and Robert Hoffstetter
Published online: 15/05/1972

Keywords: Anura; Palaeogeography; Systematics

https://doi.org/10.18563/pv.5.4.157-177

  Abstract

    The Palaeobatrachidae until now have not been reported from France. The present note makes known the discovery of very significant remains in three Tertiary localities of France: Cernay (late Paleocene), Laugnac (late Aquitanian) and Sansan (middle Helvetian). The osteologic characters, as well as the geographic and stratigraphic distribution of the family are re-stated with added details. The Palaeobatrachidae are a European family known from the late Jurassic of Catalonia (publication in course by J. Seiffert) to the Plio-Pleistocene (pre-Mindel) of Poland and Rumania. By their way of life and certain osteologic characters they are similar to the Pipidae, but they are distinguished by profound differences. It would be rash to include them in the Pipoidea or even in the Aglossa. They are apparently an independant group, essentially holarctic, which held in Europe a role equivalent to that played by the Pipidae south of Tethys. 


  PV article infos

Published in Vol. 05, Fasc. 4 (1972)

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Etude du crâne de Pachynolophus lavocati n. sp. (Perissodactyla, Palaeotheriidae) des Phosphorites du Quercy
Jean-Albert Remy
Published online: 15/02/1972

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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Les serpents des phosphorites du Quercy
Jean-Claude Rage Logo
Published online: 20/12/1974

Keywords: Grande Coupure; Quercy Phosphorites; Serpents

https://doi.org/10.18563/pv.6.3-4.273-303

  Abstract

    A short review of the genera and species of snakes from the Quercy's phosphorites described by former authors is followed by the study of specimens recently collected. Most of these latter specimens belong to the Aniliidae, Boidae, Colubridae and to the Scolecophidia; the precise systematic position of some of them is not defined yet. The following genera and species are described: Eonilius europae nov. gen. and nov. sp., Platyspondylia lepta nov. gen. and nov. sp., Coluber cadurci nov. sp. and Dunnophis cadurcensis nov.  sp.; a species described by de Rochebrune (Palaeopython filholi) is revised. One of the most important conclusions of this study is that the Colubridae appear as early as the Upper Eocene. The stratigraphic repartition of these snakes shows that the rich Upper Eocene fauna is followed by the very reduced fauna of the Lower Oligocene; then the oligocene «Grande Coupure» corresponds to a very important faunistic renewal. The fauna remains poor and little diversified during the beginning of the Middle Oligocene after which there is a new faunistic explosion. 


  PV article infos

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

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Sur le plus ancien Lagomorphe Européen et la "Grande Coupure" Oligocène de Stehlin
Nieves Lopez-Martinez and Louis Thaler
Published online: 01/01/1974

Keywords: Grande Coupure; Lagomorphe; Oligocene

https://doi.org/10.18563/pv.6.3-4.243-251

  Abstract

    Pour la première fois un spécimen de lagomorphe a été récolté en Quercy. L'intérêt de ce fossile tient surtout à son âge géologique inattendu, qui recule considérablement la date de première apparition en Europe de cet ordre de mammifère, Ceci nous paraît justifier une nouvelle réflexion sur la « grande coupure» oligocène, 


  PV article infos

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

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

Keywords: Insectivores; Leptictidae; Quercy Phosphorites

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

  Abstract

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


  PV article infos

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

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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
Published online: 15/06/1999

Keywords: endocranial cast; Epitympanic sinus; Palaeotheriidae; Paléogène; Quercy Phosphorites; skull anatomy

https://doi.org/10.18563/pv.28.1.75-87

  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. 


  PV article infos

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

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Crivadiatherium iliescui n. sp., nouvel Embrithopode (Mammalia) dans le Paléogène ancien de la dépression de Hateg (Roumanie).
Constin Radulesco and Jean Sudre
Published online: 30/12/1985

Keywords: Embrithopods; Late Eocene; Paleobiogeography; Romania

https://doi.org/10.18563/pv.15.3.139-157

  Abstract

    The investigations undertaken at Crivadia (Hateg Depression, Hunedoara District, Romania), the type locality of Crivadiatherium mackennai RADULESCO el al. (Radulesco, Iliesco et lliesco, 1976), led to the discovery of remains of a new Embrithopod. Close to the above mentioned species, but larger in size, this animal is here described as a new species of Crivadiatherium, C. iliescui. ln addition, the comparison made between the forms indicated above and Palaeaamasía kansui OZANSOY from the Eocene deposits of Anatolia (Ozansoy, 1966; Sen et Heintz, 1979) showed that the latter species included a heterogeneous material; this permitted us to distinguish the form in the Anatolian locality Ciçekdag-Arabin Kôyü under the name Palaeoamasia sp. The geographical distribution and diversity of the Embrithopod species under discussion (Balkan, Anatolia) support the idea of an eurasiatic origin of this group and seem to suggest the existence during the Eocene of a particular faunal province in south-eastern Europe. 


  PV article infos

Published in Vol. 15, Fasc. 3 (1985)

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Evolution of the Rhizomyine zygoma
Lawrence J. Flynn Logo, Mohammed Sarwar and Jean-Jacques Jaeger Logo
Published online: 30/12/1985

Keywords: parallel evolution; Rhizomyidae; Rodentia; Siwalik; zygoma

https://doi.org/10.18563/pv.15.3.129-138

  Abstract

    Cranial anatomy of a late Miocene rhizomyid, Brafhyrhizomys cf. B. pilgrimi, provides new evidence on the origin of the dorsal, round infraorbital foramen of living rhizomyines. Primitive rhizomyids retain a myomorphous keyhole foramen with a long ventral slit that retracts upward during the evolutionary history of the Rhizomyidae. The primitive condition of the elongated ventral slit is represented by Kanisamys sivalensis. Among later burrowers the foramen shows progressive dorsal migration, the ventral slit terminating midway up the snout in B.tertracharax and B. choristos ; well above the midline of the snout in Brachyrhizamys cf. B. pilgrimi. Apparently this transformation began earlier among Rhizomyinae than among Tachyoryctinae and continued to a more derived stage in rhizomyines. ln living Rhizomyx the ventral slit is absent and only a high round hole remains at the anterior end of the zygomatic arch. 


  PV article infos

Published in Vol. 15, Fasc. 3 (1985)

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L'anatomie de Lyrocephaliscus euri (wiman), Trématosaure du Trias inférieur du Spitsberg : arrière-crâne, squelette axial et ceinture scapulaire.
Jean-Michel Mazin Logo and Philippe Janvier Logo
Published online: 30/06/1983

Keywords: skull anatomy; Spitsbergen; Trematosaurs; Trias

https://doi.org/10.18563/pv.13.1-2.13-31

  Abstract

    The formic acid preparation of a nodule collected from the Lower Triassic of Spitsbergen, and containing a skull with some associated postcranial elements of Lyrocephaliscus euri (WIMAN), precises and enriches previous descriptions of the reputedly well-known trematosaur. lt permits more detailed descriptions of the occipital region, of the course of the carotid arteries and collateral vessels, and refutes the previous description of a stapedial foramen in trematosaurs. The discovery of pleurocentres associated with the other vertebral components confirms the primitive rhachitomy of trematosaurs. 


  PV article infos

Published in Vol. 13, Fasc. 1-2 (1983)

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Les mammifères Montiens de Hainin (Paléocène moyen de Belgique) Part II : Les Condylarthres
Jean Sudre and Donald E. Russell
Published online: 30/12/1982

Keywords: Belgium; Condylarths; Louisininae; Oxyclaeninae; Paleocene

https://doi.org/10.18563/pv.12.6.173-184

  Abstract

    The Condylarths from Hainin (Hainault, Belgium) show no affinity at the generic level to those known in other Paleocene localities of Europe and North America ; they are described as new forms : Monshyus praevius n. gen., n. sp. and Prolatidens waudruae n. gen., n. sp. Monshyus praevius, discovered in only one of the levels in the excavation at Hainin, is similar to the genera Microhyus TEILHARD and Louisina RUSSELL ; with them it is included in the subfamily Louisininae (Hyopsodontidae). With respect to Microhyus and Louisina, Monshyus is distinguished by the precociously modern aspect of its upper molars, the only teeth that are referable. Prolatidens waudruae, known only by lower molars, was found in several levels in the pit at Hainin. It is an arctocyonid presenting possible relationships to the North American form Oxyprimus galadrielae ; it therefore has been provisionally attributed to the subfamily Oxyclaeninae. If this attribution is confirmed, this species will constitute the first and only representative of the group in Europe. 


  PV article infos

Published in Vol. 12, Fasc. 6 (1982)

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First evidence of an early Miocene marine teleostean fish fauna (otoliths) from la Paillade.(Montpellier,France)
Bettina Reichenbacher Logo and Henri Cappetta Logo
Published online: 15/06/1999

Keywords: Aquitanian; Biostratigraphy; La Paillade; marine deposits; Miocene; otoliths; Palaeoecology; Palaeogeography; Southern France; Teleostei

https://doi.org/10.18563/pv.28.1.1-46

  Abstract

    A fossil fish fauna, based on 5533 otoliths, from the La Paillade locality at Montpellier is described and figured. The otolith-bearing marls correlate to mammal zone MN l (Aguilar, 1982), and thus represent the earliest Miocene. The fish fauna consists of 30 taxa belonging to 20 families. Two species are new: Dussumieria sittigi and Liza gaudanti. The predominant faunal element is the Lesueurigobius vicínalis-species complex, composing 73% of all investigated otoliths. The palaeoecological analysis reveals a marine to euryhaline fish fauna living under tropical to subtropical conditions in the transition zone littoral - sublittoral. Water depth probably was more than 10 m. The scarcity of pelagic físhes suggests that the habitat was either a sheltered bay and/or far away from the open sea. Furthermore, some genera represented in the La Paillade fish fauna presently live exclusively in the Indopacific realm. Their presence strongly supports a broad connection between the Indian Ocean, the Mediterranean, and the Paratethys Seas during the Early Miocene (Aquitanian). From a palaeobiogeographical point of view, faunal relationships were found between the La Paillade fish fauna and both the Paratethys fish fauna and the fish fauna from the deposits in the Upper Rhinegraben and the Mayence and Hanau Basins (Germany).



      


  PV article infos

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

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Recherches de mammifères paléogènes dans les départements de l'Aisne et de la Marne pendant la deuxième moitié du vingtième siècle
Pierre Louis
Published online: 16/12/1996

Keywords: Biochronology; Eastern Paris Basin; Fossil localities; Mammals; paleoenvironments; Paléogène; Paleogeography

https://doi.org/10.18563/pv.25.2-4.83-113

  Abstract

    A brief historical account of fossil vertebrate discoveries in the Eastern part of the Paris Basin between the beginning of the nineteenth century and 1950 is given. Other localities discovered since then are presented. A reconstruction of past landscapes is briefly elaborated. A biozonation based on mammals is proposed, from the Late Thanetian to the Middle Bartonian. Paleogeographical considerations are added. Suggestions regarding the search for new marnmal localities are made. 


  PV article infos

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

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A new vertebrate locality in the eifelian of the khush-yeilagh formation, Eastern Alborz, Iran
Alain Blieck, Farrokh Golshani, Daniel Goujet, Amir Hamdi, Philippe Janvier Logo, Elga Mark-Kurik and Michel Martin
Published online: 01/02/1980

Keywords: Devonian; Iran; khush-yeilagh formation; Vertebrate

https://doi.org/10.18563/pv.9.5.133-154

  Abstract

    A new Devonian vertebrste locality has been discovered in 1976 in the basal part of the Khush-Yeilagh Formation in the eastern Alborz Mountains of Iran. The fossils occur in a band one centimeter thick which is identifiable at other outcrops in the area. A preliminary study of the remains has yielded the following faunal list : Placodermata (Phlyctaeniida indet.. Groenlandaspididae indet.. Coccosteidae indet., Holonema sp., Ptyctodontida indet., Antiarcha indet., Bothriolepis cf. kwangtungensis), Elasmobranchii (Ctenacanthidae indet.), Acanthodii (Gyracanthus sp., « Onchus » overathensis, Ischnacanthiforme indet.), Dipnoi (? Dipteridae indet.), « Crossopterygii ›› (Onychodus cf. sigmoides, Holoptychiidae indet., Osteolepididae indet.). This fauna is older than the Middle Givetian and probably of Middle or Lower Eifelian age. Owing to its diversity, it may prove possible to use it in the future as a reference fauna for the study of the Devonian vertebrates in Central Asia and the Middle East. 


  PV article infos

Published in Vol. 09, Fasc. 5 (1980)

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

Keywords: Aplodontidae; Europe; Oligocene

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

  Abstract

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


  PV article infos

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

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Page 11 of 19, showing 20 record(s) out of 366 total