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Page 13 of 18, showing 20 record(s) out of 359 total

The skull of Tetraceratops insignis (Synapsida, Sphenacodontia)
Frederik Spindler
Published online: 1/9/20

Keywords: cranium; pelycosaur; Permian; therapsid origins

https://doi.org/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


  PV article infos

Published in Vol 43-1 (2020)

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New material of “Eurysternidae” (Thalassochelydia, Pan-Cryptodira) from the Kimmeridgian of the Swiss Jura Mountains
Christian Püntener, Jérémy Anquetin and Jean-Paul Billon-Bruyat
Published online: 6/25/20

Keywords: Eurysternidae; Late Jurassic; morphology; Switzerland; Testudines; Thalassochelydia

https://doi.org/10.18563/pv.43.1.e2

  Abstract

    The region of Porrentruy (Swiss Jura Mountains) is known for its rich and diverse assemblage of Late Jurassic coastal marine turtles (Thalassochelydia). Dominated by the “Plesiochelyidae”, this assemblage also includes representatives of the two other thalassochelydian groups, the “Thalassemydidae” and “Eurysternidae.” In this study, we present new shell-based material from Porrentruy referable to eurysternids. One specimen represents a juvenile individual or a relatively small taxon, and is notably characterized by a well fenestrated plastron exhibiting a wider than long central plastral fontanelle. Two other specimens are much larger and possibly represent the largest eurysternids known to date. The fourth specimen is characterized by a unique plastral morphology otherwise only known in very small juveniles. This is the first time this unique plastral morphology is known to persist in an adult or subadult. The new material described herein represents at least three distinct taxa, all of them probably new. However, we refrain from naming new species based on this incomplete material in order to avoid adding confusion to an already complex taxonomical situation. This study provides new insights into the great diversity of eurysternids during the Late Jurassic. 


  PV article infos

Published in Vol 43-1 (2020)

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Physogaleus hemmooriensis (Carcharhinidae, Elasmobranchii), a new shark species from the early to middle Miocene of the north sea basin.
Thomas Reinecke and Kristiaan Hoedemakers
Published online: 10/15/06

Keywords: Carcharhinidae; Early Miocene; Elasmobranchii; Hemmoorian; new species; North Sea Basin; Physogaleus

  Abstract

    A new carcharhinid shark species, Physogaleus hemmooriensis sp. nov., is described from the Lower Hemmoorian (Behrendorfian, late Burdigalian, early Miocene) of Werder, Lower Saxony, Germany. P. hemmooriensis also occurs in the Edegem and Antwerpen Sands Members of the Berchem Formation, Belgium, and in the Miste Bed, Aalten Member of the Breda Formation, The Netherlands, which have an early to middle Miocene age. In the Western Atlantic region, the taxon is present in the early Miocene Calvert Formation of Delaware, U.S.A, which is largely contemporaneous with the Hemmoorian. 


  PV article infos

Published in Vol. 34, Fasc. 1-2 (2006)

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The eosimiid and amphipithecid primates (Anthropoidea) from the Oligocene of the Bugti hills (Balochistan, Pakistan): new insight into early higher primate evolution in South Asia.
Laurent Marivaux
Published online: 10/15/06

Keywords: Amphipithecidae; anthropoid phylogney; Bugti Hills; Early Oligocene; Eosimiidae; Pakistan

  Abstract

    Eosimiid and amphipithecid primates document a long and significant history of primate evolution throughout the Eocene in Southeast Asia. Despite the absence of a comprehensive post-Eocene fossil record, it was generally hypothesized that both families left no descendant in Asia. Recently, two new small-bodied taxa, Bugtipithecus and Phileosimias, have been recovered in early Oligocene coastal deposits from the Bugti Hills (Balochistan, central Pakistan) and referred to the families Amphipithecidae and Eosimiidae, respectively, on the basis of dental fossil remains. In this paper, we provide more exhaustive description, comparison, and discussion of these taxa. As for tarsiid and sivaladapid primates, the persistence of eosimiids and amphipithecids into the Oligocene clearly demonstrates that low latitudes of South Asia provided a continuous access to tropical refugia during the climatic deterioration characterizing the late Eocene-early Oligocene interval, which was seemingly lethal for primate communities elsewhere across the Holarctic continents. As a contribution to the ongoing phylogenetic debates regarding the position of eosimiids and amphipithecids on the primate family tree, we have performed a cladistic analysis in a high-level primate systematic context in order to assess the position and the role of these new taxa in that phylogenetic issue. Our results support the view according to which eosimiids and amphipithecids (and by extension Phileosimias and Bugtipithecus, respectively) are stem anthropoids. These fossils from Pakistan document an unsuspected Oligocene phase of the evolutionary history of anthropoid primates in southern Asia, which clearly enhances the extent of the anthropoid radiation in this province during the Paleogene. Several phylogenetic and paleobiogeographic aspects are discussed, notably the intra- and inter-relationships between Paleogene Asian and Afro-Arabian anthropoids, and the resulting potential dispersal models between both land-masses during the Paleogene. 


  PV article infos

Published in Vol. 34, Fasc. 1-2 (2006)

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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
Published online: 1/20/69

Keywords: Fauna; Mammalia; Pleistocene; Tennessee

https://doi.org/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. 


  PV article infos

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

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Les vertébrés fossiles de Colombie et les problèmes posés par l'isolement du Continent sud-Américain.
Jaime de Porta
Published online: 1/20/69

Keywords: Columbia; Cretaceous; Fauna; Quaternary; South America

https://doi.org/10.18563/pv.2.2.77-94

  Abstract

    A general view is given of the vertebrate faunas, Cretaceous to Quaternary of age, found in Columbia and of their principal characteristics. This view leads to the discussion of the isolation of the South American continent and of the role played by the Bolivar syncline with respect to North American immigrants during the Oligocene. The absence of marine deposits of Oligocene age in the north and northwest of Columbia suggests the possibility of a communication with Central America. This communication would have permitted the passage of hystricomorph rodents, of platyrrhine monkeys, and of colubrids. The non-occupation, until then, of the ecologie niches of these groups would have favored their installation beside the indigenous fauna. In this hypothesis it would no longer be necessary to admit that these vertebrates arrived as «island hoppers ››. The eco-biologic conditions would explain the absence of large-sized forms of North American origin. 


  PV article infos

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

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Les gisements de Robiac (Eocène supérieur) et leurs faunes de Mammifères.
Jean Sudre
Published online: 4/5/69

Keywords: Fauna; Late Eocene; Mammalia; Robiac

https://doi.org/10.18563/pv.2.3.95-156

  Abstract

    Designated the type-locality of a late Eocene paleomammal zone, Robiac has recently been the object of important excavations. The first results of the new collecting, as  well as a revision of the material in old collections, are given in this work.
    Two stratigraphic section, cutting through the two sites presently distinguished (Robiac-Nord and Robiac-Sud) reveal the lithologic variation at the base of the Fons Limestone and the localization of three fossiliferous beds at Robiac-Sud.
    The molluscan fauna and the flora (charophytes), which have already been described, as well as that of the lower vertebrates, have been listed.
    A list of 46 mammalian species (only 16 species were known previous to 1964) has been established. The micro-mammals, nearly all new in this fauna (marsupials, insectivores, bats, rodents, primates, and some smallsized artiodactyls), Were obtained only after screen-washing of the matrix; about 4 tons of sediment were thus treated.
    The artiodactyls have been the most extensively analyzed; 6 genera, of which one is new, have been recognized. The latter is described as Robiacina minum n.g., n.sp., and represents a very small artiodactyl of the family Anoplotheriidae. The taxonomie status of certain species formerly described has been clarified by the designation of lectotypes (Cebochoerus robiucensis, Catodonerium robiacense, Xiphodon castrense).
    The paleontologic corrélations at present possible between the late Eocene faunas have allowed the relative positions of te different French localities of this age to be established; the Guépelle locality, it seems, could define in the future a new paleomammal zone.
      


  PV article infos

Published in Vol. 02, Fasc. 3 (1969)

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Rongeurs de l'Oligocène moyen provenant de nouvelles fouilles dans les phosphorites du Quercy
Monique Vianey-Liaud
Published online: 9/15/69

Keywords: Oligocene; Quercy Phosphorites; Rodents; Theridomys

https://doi.org/10.18563/pv.2.5.209-239

  Abstract

    A recent campaign of excavations (1965-68) undertaken by the Laboratoire de Paléontologie of Montpellier in pockets of the Quercy phosphorites, has permitted the dating of several localities thanks to the analysis of their micromammalian fauna.
    The rodents of localities belonging to the middle Oligocene (La Sauvetat zone) are the object of this study. This rodent fauna has been compared to the forms coming from three stratified localities belonging to the biochronologic zone of La Sauvetat :  Balm, Montalban and Lovagny.
    The abundance of material, notably of theridomyids and cricetids, permitted a summary statistical study to be effected and gave some precise details on the variability of the species (Theridomys varians in particular). Other details were provided on certain groups, notably on the upper teeth of Scíuromys cayluxi and on the milk teeth of theridomyids. Some specimens of «Sciurus» sp. and of Plesispermophilus angustidens were collected. By this means, it has been possible to establish, for the first time, a precise upper limit to the epoch of their appearance in Europe. 


  PV article infos

Published in Vol. 02, Fasc. 5 (1969)

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Contribution à la classification des pistes de vertébrés du Trias: Les types du Stormberg d'Afrique du Sud (1).
Paul Ellenberger
Published online: 10/16/72

Keywords: Footprints; South Africa; Stormberg; Trias

  Abstract

    No abstract available 


  PV article infos

Published in Vol. 5, Ext (1972)

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Une nouvelle espèce d'Hipparion du Miocène terminal d'Espagne.
Miquel Crusafont i Pairó and P. Sondaar
Published online: 1/31/71

Keywords: Hipparion; Late Miocene; Spain; Villafranchian

https://doi.org/10.18563/pv.4.2.59-66

  Abstract

    The recently discovered, very rich, Pliocene locality of Layna (Soria, Spain), has already yielded 30 species of mammals. Hipparion fissurae, described here is more dolichopodic than other Hipparion. It is related to Hipparion crusafonti from Villaroya (Villafranchian), but more slender between other characters.
      


  PV article infos

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

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Révision des Chiroptères Lutériens de Messel (Hesse, Allemagne).
Donald E. Russell and Bernard Sigé
Published online: 4/4/70

Keywords: Chiroptera; Lutetian; Messel

https://doi.org/10.18563/pv.3.4.83-182

  Abstract

    The revision of the Lutetian chiropterans from Messel, first described by Revilliod in 1917, is based on the anatomy of the teeth and the skeleton.  A figuration or refiguration of thematerial utilized accompanies the new description, which goes beyond that of the original monograph.
    The study shows a certain variability of the dental structure within the genera Palaeochiropteryx Revilliod and Archaeonycteris Revilliod,  as well as a general resemblance of the two forms. The morphology of the teeth permits, however, the verification of the validity of the different species: Palaeochiropteryx tupaiodon Revilliod, P. spiegeli Revilliod, Archaeonycterís trigonodon Revilliod, and Archaeonycteris revilliodi, n. sp.
    Some differences of the skeletal and dental anatomy tend to indicate a stage of evolution less advanced for the genus Archaeonycteris.
    The comparison of the chiropterans of Messel with the principal groups of living chiropterans, as well as with different Eocene fossíls (notably Cecílionycteris Heller and Icaronycteris Jepsen) leads to a more precise idea of the anatomy of primitive chiropterans. This comparison also permits the proposition that the oid forms so far described by integrated in a superfamily, the Palaeochiropterygoidea and allows   a general phylogenetic hypothesis to be advanced for the order Chiroptera. 


  PV article infos

Published in Vol. 03, Fasc. 4 (1970)

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Introduction à l'oeuvre scientifique de Donald E. Russell, "gentleman paleontologist"
Marc Godinot and Phillip D. Gingerich
Published online: 12/16/96

Keywords: D.E.Russell; Eocene; Mammals; Paleocene; Paleontology; synthesis

  Abstract

    The scientific career of D.E. Russell began with a Pliocene fauna from Oregon, and then turned in the direction of European Paleogene mammals. Field work followed by study of the mammals that were collected, firstly in the Paleocene and later in the early Eocene, greatly rejuvenated learning in this field. Syntheses on the Northwest European Tertiary basin and on European marnmals and stratigraphy came next. Research on the Eocene of Asia was carried out jointly with Gingerich on Pakistan and with Dashzeveg on the faunas of Mongolia. An important synthesis on the entire Paleogene of Asia, joint with Zhai, followed. Field work in Africa with Sigogneau-Russell led to the discovery of Mesozoic mammals there. A synthesis of mammalian paleofaunas of the world was written with Savage, and a similar synthesis of Cenozoic vertebrate faunas is currently being prepared. These achievements reflect the perennial importance of field work, numerous collaborations with both amateurs and professionals, and the human qualities of this author.
      


  PV article infos

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

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Avant-propos
Marc Godinot and Phillip D. Gingerich
Published online: 12/16/96

Keywords: D.E.Russell

  Abstract

    Le présent volume est l'aboutissement d'un projet né il y a presque cinq ans. En décembre 1991, l'un d'entre nous (MG) prenait des contacts en vue de proposer un symposium sur les mammifères fossiles, dédié à D.E. Russell, dans le programme du 4e Congrès de la European Society for Evolutionary Biology. Ce congrès, baptisé "Evolution 93", devait se tenir à Montpellier en août 1993. Son Comité d'Organisation, animé par F. Catzeflis, recherchait des organisateurs de symposiums. L'idée fut acceptée avec enthousiasme par le second d'entre nous (PDG), et le titre de notre Symposium fut précisé: " Palaeobiology and Evolution of Early Cenozoic Mammals - A Symposium in Honor of D.E. Russell". Le projet fut formellement accepté par le Comité d'Organisation en avril 1992. 


  PV article infos

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

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Rongeurs Miocènes dans le Valles-Penedes 2 : Les rongeurs de Castell de Barbera
Jean-Pierre Aguilar, Jordi Agusti and J. Gibert
Published online: 4/20/79

Keywords: Castell de Barbera; Miocene; Rodents; Valles-Penedes

  Abstract

    The rodent-fauna (Cricetidae and Gliridae) recently found at Castell de Barbera (Spain) is similar to those from the other locslities of the Valles - Penedes - Can Ponsic 1 and Can Llobateres - : same composition and similar evolutionary level of the different species. On the other hand this fauna is different from those of Upper Vindobonian and Vallesian localities of the Calatayud - Teruel area. Castell de Barbera has an intermediate chronological position between the localities of Anwil (Switzerland) and Can Ponsic 1. It is still not possible to validate or invalidate the initial attribution based on absence of Hipparion of Castell de Barbera to the Upper Vindobonian. 


  PV article infos

Published in Vol. 09, Fasc. 1 (1979)

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Evolution des Aplodontidae Oligocènes Européens
Norbert Schmidt-Kittler and Monique Vianey-Liaud
Published online: 10/1/79

Keywords: Aplodontidae; Europe; Oligocene

  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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Contribution à la classification des Pistes de Vertébrés du Trias : les types du Stormberg d'Afrique du Sud (2 ème Partie: le Stormberg supérieur - 1. Le biome de la zone B/1 ou niveau de Moyeni: ses biocénoses).
Paul Ellenberger
Published online: 12/1/74

Keywords: biocenosis; Footprints; South Africa; Stormberg; Trias

  Abstract

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

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

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

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

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

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

      


  PV article infos

Published in Vol. 6, Ext (1974)

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New records of the pantodont Archaeolambda from the Paléocène of southern China
Suyin Ting, Judith A. Schiebout and Jianjian Zheng
Published online: 12/16/96

Keywords: Archaeolambda; China; Paleocene; Pantodont

  Abstract

    Two new finds of pantodont materials from southern China, assigned to Archaeolambda, are described in this paper. One, a new species from the Nanxiong Basin, Guangdong Province, is similar to Alcidedorbignya inopinata from the early Paleocene of Tiupampa, Bolivia in size. It provides reliable evidence of the occurrence of Archaeolambda in the early-middle Paleocene of southern China. The second find includes specimens of Archaeolambda sp. cf. A. planicanina from the ?late Paleocene of Hengyang Basin, Hunan Province, which are the first record of a fossil mammal from the area near Hengyang city. The only vertebrate fossils previously found here were two genera of crocodiles discovered in 1938. This find sheds new light on the local biostratigraphy. 


  PV article infos

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

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Norselaspis glacialis n.g., n.sp, et les relations phylogénétiques entre les kiaeraspidiens (Osteostraci) du dévonien inférieur du Spitsberg.
Philippe Janvier
Published online: 6/15/81

Keywords: Devonian; kiaeraspids; Osteostraci; Spitsbergen

  Abstract

    The anatomy of Norselaspis glacialis n.g., n.sp., a primitive kiaeraspidian from the Lower Devonian of Spitsbergen, is described on the basis of spécimens studied by grinding sections or prepared with dilute formic acid. This study yielded some new anatomical details, including the presence of a canal prolonging posteromedially the canal alloted to the facial nerve by Stensiö. This posterior prolongation of the « facial canal ›› into the posterolateral part of the labyrinth cavity is consistent with the hypothesis put forward by Allis, Lindström, Jefferies and Whiting, that this canal housed the glossopharyngeus nerve. Furthermore, in N. glacialis, the foramen usually referred to as the foramen for the œsophagus opens posteriorly into a cavity in the postbranchial wall, referred to here as the intramural cavity, and which is interpreted as having housed the heart. Consequently, the œsophagus probably accompanied the dorsal aorta through the aortic canal. Finally, the foramen generally interpreted as having transmitted the ventral afferent arterial trunk is here considered as having housed the hepatic vein, which emptied into the venous sinus of the heart. The ventral afferent arterial trunk may thus have passed through the former «œsophageal ›› foramen.
    The problem of the position of the dorsal nerves in the Osteostraci is discussed, and it is suggested that the three foremost nerve canals opening into the oralobranchial cavity housed the maxillary ramus of the trigeminus, the facial nerve and the glossopharyngeus nerve respectively. The mandibular ramus of the trigeminus must have accompanied one of the two foremost nerves, but for the moment it is impossible to decide which.
    The problem of the nature of the interbranchial crests of the Osteostraci is briefly discussed. Comparison with the branchial apparatus of the Petromyzontida does not support the hypothesis that the interbranchial crests are part of the branchial arches, incorporated into the endoskeletal shield. A different hypothesis is proposed, that the branchial skeleton of the Osteostraci was situated entirely inside the oralobranchial cavity, and was attached to the endoskeletal shield only by the ventromedial processes. The grooves classically allotted to the efferent branchial arteries would thus have housed extrabranchial arteries, branching off from the dorsal aorta, and irrigating the ventral branchial musculature.
    A phylogeny and a classification of the kiaeraspidians are proposed. The evolution of this monophyletic group is characterized by, e.g., reduction of cornual processes, shortening of the abdominal division of the shield, subdivision of the lateral fields, and enlargement of the supraoral fossae.
    The phylogenetic position of the kiaeraspidians within the Osteostraci remains uncertain. Their sister-group may be either the benneviaspidiens or the thyestidians, or Thyestes alone (in which case they would have to be included within the thyestidians). 


  PV article infos

Published in Vol. 11, Fasc. 2-3 (1981)

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Premier signalement du Monachinae (Phocidae, Mammalia) dans le Sahélien (Miocène supérieur) d'Oran (Algérie)
Christian de Muizon
Published online: 10/15/81

Keywords: Algeria; Late Miocene; Phocidae

  Abstract

    Messiphoca mauretanica nov. gen., nov. sp. représente le premier Phocidae fossile recensé en Afrique du Nord. Provenant du gisement sahélien (Miocène supérieur) de Raz-el-Aïn (Algérie), il est connu par quelques os du membre antérieur (humérus, radius, ulna), quelques vertèbres dorsales et un crâne très fragmentaire. La description de cette forme nouvelle amène à considérer Messiphoca mauretanica comme un Monachinae archaïque proche de l'origine du groupe Pliophoca - Monachus. L'incidence de cette interprétation d'un Phocidae «pré-Messinien ›› sur la crise de salinité du Messinien est aussi envisagée. 


  PV article infos

Published in Vol. 11, Fasc. 5 (1981)

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Les rongeurs du site Pliocène à Hominidés de Hadar (Ethiope)
Maurice Sabatier
Published online: 2/15/82

Keywords: Ethiopia; hominids; Muridae; Pliocene

  Abstract

    The intensive exploration of the Pliocene Hadar Formation, rich in hominid remains, led us to the discovery of several micromammals levels. ln some of them, rodents are very abundant. The stratigraphic repartition of these levels do not cover the whole fossiliferous series of the formation but takes place only in the sedimentary members from Sidi Hakoma and Denen-Dora (rancing from 3.1 - 3.2 MY to 2.8 - 2.9 MY, according to the recent geochronological data). During this gap of time, the species do not show morphological changes, what allowed us to gather, in the same taxa, forms of slighty different ages.
    Two striking facts, giving a lot of indications, characterize these small rodents'faunas. First, we notice the domination of the Muridae, as well on a qualitative way (number of species) as on a quantitative one (number of individuals). Then, it appears that, until now, two genera of these murids were known only in the south-western asiatic regions. So, we can suppose continuous biotops between Africa and Indian Subcontinent before 3 MY. In this hypothesis, the hominids had already the possibility to leave their african « cradle ››. Finally, almost all studied genera are still represented at the present time. This fact, previously observed in Laetolil, Omo, Olduvai contributes to remove hope of establishing a biochronological scale based on rodents, in tropical zone. Nethertheless, that allows to try a reconstruction of the palaeoenvironnement, by using the principle of actualism.
      


  PV article infos

Published in Vol. 12, Fasc. 1 (1982)

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