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The Ctenodactylidae (Rodentia) from the Oligocene of Ulantatal (inner Mongolia, China)
Monique Vianey-Liaud, Norbert Schmidt-Kittler and Laurent Marivaux
Keywords: Adaptive radiation; Ctenodactylidae; Mongolia; Oligocene; Rodents
 
  Abstract

    This paper proposes a systematic revision of the Oligocene Mongolian Ctenodactylidae, on the basis of abundant material obtained by screen/washing operations in stratified localities of the Ulantatal area (Inner Mongolia) (UTL1, 2, 3, 4, 5, 7, 6 & 8). A Chinese-German team has collected several thousands of isolated rodent teeth, and a number of fragmentary jaws. A new genus is identified (Alashania nov. gen. tengkoliensis nov. sp.), and eight former species are reevaluated, Karakoromys decessus, Tataromys sigmodon, T. minor, T. plicidens, Yindirtemys ulantatalensis, Y. bohlini, Y. deflexus, with several synonymies. A new Yindirtemys species is described: Y. shevyrevae nov. sp. and another one close to that: Y. aff. shevyrevae nov. sp. Four new species, which are rare in the localities, remain in open nomenclature because they are not well-represented. Yindirtemys differs from the other genera by the permanence of crescentic structures, while the other genera show a general reduction of the trigonoid area (= anterior valley). We define a range of size variation for each well documented population. Although the dental morphology shows a wide range of variation, given that transitional morphologies occur in a single locality, it is possible to provide a clear definition for most species. We show that dental patterns of the different genera can be derived from the pattern of Karakoromys. As a number of Tataromyinae have been determined in several localities from China, Kazakhstan and Mongolia, usually on the basis of scarce material, or surface collections, the present study would be used to re-evaluate their attribution inasmuch as the taxa are now placed in the Oligocene stratigraphy. The diversity of sizes and forms reflects the adaptive radiation of the family during the Oligocene, within a forested environment where the vegetation was probably abundant. 


  Article infos

Published in Vol. 34, Fasc. 3-4 (2006)

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Acinoptèrygiens du Stéphanien de Montceau-les-Mines (Saône-et-Loire, France).
Daniel Heyler and Cécile Poplin
Keywords: Aeduelliforms; Biogeography; Palaeonisciforms; paramblypteriforms; Stephanien
 
  Abstract

    The study of new specimens from the Stephanian shales of Montceau-les-Mines confirms and enlarges the number of groups already known in this area. Among the Palaeonisciforms, “form A" is now known more completely, although no diagnosis or name can yet be given for it. “Form B" is redescribed and its relationships with “Elonichthys robisoni" are discussed. A palaeoniscid is recorded which resembles those from Bourbon l'Archambault. The paramblypteriforms occur rather frequently, but no genera can be determined. The aeduelliforms comprise some specimens close to Aeduella blainvíllei from Muse (Autun basin), and a new genus. Comparison of the latter with two fossils from Lally allows creation of two new species and a new family. This diversification of the aeduelliforms during this middle Stephanian leads to the hypothesis that the group originated at least as early the lower Stephanian. This material prooves again the characteristic endemism of this fauna, particularly of the aeduelliforms which are known only in the Massif Central where they diversified during the Permo-Carboniferous. Biogeographical consequences are discussed. 


  Article infos

Published in Vol. 13, Fasc. 3 (1983)

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New records of the pantodont Archaeolambda from the Paléocène of southern China
Suyin Ting, Judith A. Schiebout and Jianjian Zheng
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. 


  Article infos

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

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Experimental taphonomy inavian eggs and eggshells: effects on early diagenesis.
Ana M. Bravo, D. A. Buscalioni, Lauro Merino and B. G. Müller
Keywords: archosaurian eggshells; avian egg; Experimental taphonomy; geochemical analysis; pyritisation; Upper Cretaceous
 
  Abstract

    We experimentally explore the early taphonomic stages involving the decay and biodegradation of buried eggs and eggshells. Unfertilised commercial chicken eggs and eggshell fragments were buried in plastic containers and were kept under controlled conditions for eight months. Half of the containers were filled with marl, and the remainder with sand. All were saturated with fresh tap water, acidified water, sulphate water, or seawater. They were kept in the dark at 23.4-26 °C, except one, which was kept in a heating chamber at 37.4°C. We expected that different burial conditions would produce distinct taphonomic outcomes. Instead, the taphonomic alterations of buried eggs parallel that of the alteration of egg proteins (i.e., denaturation and/or putrefaction) with an additional role played by the eggshell. Mummification, encrustation, distortion and fragmentation, and necrokynesis (vertical displacement) depend on organic matter decay. The experiment identifies environmental conditions that may favour or actively promote these taphonomic processes. Of these, early pyritization is one of the most relevant. For comparative purposes, samples of fossil and extinct eggshell representing three distinct environmental burial conditions were examined. These included Megaloolithus, Caiman crocodilus, and Struthio camelus ootypes. The geochemical analysis of these eggshells showed no significant differences among the chemical variables of these fossil and extant ootypes. Eggshells exhibited a stable composition over a range of experimental conditions. 
      


  Article infos

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

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Old world hemiones and new world slender species (Mammalia, Equidae)
Véra Eisenmann, John Howe and Mario Pichardo
Keywords: Amerhippus; biometry; Equus; Holocene; New World; Old World; Osteology; Pleistocene; Pliocene

doi: 10.18563/pv.36.1-4.159-233
 
  Abstract

    Morphological and biometrical description of skulls, teeth, and limb bones of extant and fossil Old World herniones (including E. hydruntinus) and of New World 'stilt-Iegged' and other slender species from Blancan to Holocene. An Appendix presents ways in which the approximate size of some missing bones or dimensions may be deduced from available ones.

    The discussed and/or illustrated fossils were found in Bolivia (Tarija), Canada (Yukon), China (Choukoutien, Gulongshan, Jiling, Loufangzi), Ecuador (Oil Fields), Ethiopia (Melka Kunturé), France (Lunel-Viel), Germany (Süssenborn), Greece (Agios Georgios, Petralona), Hungary (Dorog), Italy (Romanelli), Mexico (Cedazo, San Josecito), Mongolia (Sjara-osso-gol), Spain (Venta Micena), ex-Soviet Union (Akhalkalaki, Binagady, Chokurcha, Chukochya, Kabazi, Kolyma, Krestovka, Kurtak, Staroselie, Tologoj), USA (Alaska, Arkalon, Cedar Meadow, Channing, Conkling, Dry Mountains, Hay Springs, Leisey Shell Pit A, Lissie Formation, Natural Trap, Pool Branch, Powers Ranch, Rock Creek, San Diego, Santo Domingo, Seymour Formation, Shelter, Slaton, Trinity River). Numerous raw or statistically elaborated data are given in Tables.

    There is no evidence for the existence of Old World hemiones in the New World nor of 'stilt-Iegged' equids in the Old World. The first 'stilt-Iegged' equid was found at Santo Domingo, New Mexico, and is believed to be Late Blancan. It was probably at the origin of E. calobatus (Arkalon, Rock Creek) and of the smaller E. semiplicatus (Channing, Rock Creek). Slender, but not 'stilt-Iegged', equids found at Natural Trap, Wyoming, ca. 12 ky ago belong to Amerhippus. AlI these species share with Oid World Sussemiones (and some hemiones) peculiar patterns on the lower cheek teeth.

    The slender Equus sp. B of Leisey Pit A, Florida, ca. 1.2 Ma, as weIl as Amerhippus francisci and E. tau (probably a senior synonym of E. quinni) share conventional lower cheek teeth patterns. The skulls of A. francisci and E. tau, however, are quite different.

    Paleontological data suggest a common origin of Amerhippus, Sussemiones, and 'stilt-Iegged' equids during the late Blancan. Old World hemiones seem to have differentiated later. 


  Article infos

Published in Vol. 36, Fasc. 1-4 (2008)

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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
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. 


  Article infos

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

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Muridae (Rodentia) du Pliocène supérieur d'Espagne et du midi de la France.
Jacques Michaux
Keywords: Anthracomys meini; Castillomys crusafonti; Pliocene; Rodents; Valerymys ellenbergeri

doi: 10.18563/pv.3.1.1-25
 
  Abstract

    The murid fauna of the terminal Pliocene of southwest Europe is rich in at least eight genera and ten species. With the species belonging to the genera Apodemus, Rhagapodemus, and Stephanomys not being studied here, the study of the other murids resulted for one thing in the description of three new genera and three new species: Castillomys crusafonti n. g., n. sp., Occitanomys brailloni n. g., n. sp., Anthracomys meini n. sp., Valerymys ellenbergerí (THALER) n. g., and for another thing in the recognition of a form hitherto unknown in this region, Micromys praeminutus KRETZOI. Systematic study has shown that certain species of the terminal Pliocene fauna had their ancestors in the Turolian fauna presently known in Spain. The evolutionary lineages thereby recognized have been studied more in detail and a list of the evolutionary tendencies of the dendal characters has been given. A chart of the probable phyletic relationships between the different murids of the Pliocene faunas of southwest Europe (With the genus Rhagapodemus and Apodemus dominans being excluded) is given in conclusion of this work. 


  Article infos

Published in Vol. 03, Fasc. 1 (1969)

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

doi: 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. 


  Article infos

Published in Vol 43-1 (2020)

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Le genre Plagiolophus (Palaeotheriidae, Perissodactyla, Mammalia): révision systématique, morphologie et histologie dentaires, anatomie crânienne, essai d'interprétation fonctionnelle
Jean-Albert Remy
Keywords: New taxa; Paléogène; perissodactyls; skull anatomy; tooth histology
 
  Abstract

    The genus Plagiolophus is documented, almost solely in Western Europe, from the middle Eocene up to the mid Oligocene (MP 12 to MP 25), i.e. more than for 15 MY. Seventeen species are now recorded whose two of them are new, P. ringeadei nov. sp. and P. mamertensis nov. sp. Some anatomical variations and the deflection of certain evolutionary trends justify the distinction of three subgenera, Paloplotherium, Fraasiolophus nov. and Plagiolophus s.s. The genus displays a wide range in size and weight (between 10 and 150 kg). The detailed description of the skull of several species is here given for the first time.
    Despite important evolutionary drifts during this long time span, the dentition shows a great structural homogeneity, which renders difficult the determination of fragmentary specimens or isolated teeth. It is characterized by a great heterodonty; premolars are little molarized and present a certain regression through time with paradoxically some progress in the molarization. The hypsodonty increases: the first Plagiolophus are hardly less brachyodont than Propalaeotherium, and the last ones are nearly as hypsodont as Merychippus from the early Miocene. The upper molars change from a wide crown pattern, with an open occlusal surface, lightly oblique transverse lophs and rounded internal cusps, to a narrower pattern, with a frontally constricted occlusal surface and internal lophs aligned parallel to the ectoloph. The M3/3 become always longer.

    The dental enamel displays horizontal Schreger-bands with imprecise limits occupying only the middle part of the enamel layer. The dentine is remarkable by its high rate of pericanalicular dentine. The crown cementum, lacking in earlier forms, increases to the point where it fills the occlusal valleys of the
    teeth.

    The masticatory musculature shows a increasing prominence of the temporal, with probably an important role devoted to the pterygoid muscles in lateral movements related to a two-phase type of chewing.

    The evolution of the dentition, of the masticatory musculature and of the repartition of masticatory forces indicate that the Plagiolophus have known different diets through their long evolutionary history; at first browsers they became mixed feeders and finally grazers. Their relatively long neck allowed these animals to reach different vegetal layers. The strength of the nuchal crests also suggests that they were able to have strong backwards movements of the head to pull up their food.

    This evolution of diet seems related to the slow degradation of environmental conditions attested during this period in western Europe, with the generalization of more open landscapes, increasing aridity and more marked seasons.

    Besides, a remodeling of the face is ontogenetically and along time observed, in relation with the evolution of the masticatory apparatus and especially with that of the mandibular lever arm. The postcanine diastemata become longer in the course of evolution; the free extremities of the nasals are always relatively long which contradicts the hypothesis according to which Paloplotherium may have had a trunk. At last the lineage Fraasiolophus can be distinguished by the presence of a deep malar fossa, probably related to a strong development of the maxillo-labialis superior muscle.

    The orbit is always large and tends to increase in size, which indicates a good development of the vision and its increasing role in the life relations. A peculiar type of epitympanic sinus could have been used as a resonance chamber insuring a certain amplification of sounds before their transmission to the eardrum. The endocranial cast reveals a relatively large brain with an advanced degree of gyrencephaly. Beside the role eventually played in food research and social relations, these neurophysiological abilities, also related to an advance in cursorial fitness, could have contributed to the survival of these animals facing the predation pressure of the first fissipede carnivores and the competition with new immigrant herbivores after the "Grande Coupure".
    On the basis of some shared apomorphies with the Pachynolophinae, which prevent from considering the latter as Equidae (molarization of the premolars, reduction of the premaxilla dorsal apophysis, peculiar epitympanic sinus, splitting of the jugular process), the hypothesis of an autochthonous origin of Plagiolophus issued from a form near Propalaeotherium, is once again proposed and discussed. Finally, intra-generic relationships are taken into consideration. 


  Article infos

Published in Vol. 33, Fasc. 1-4 (2004)

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Rongeurs Miocènes dans le valles-Penedes 1 : Les rongeurs de Can Ponsic 1
Jean-Louis Hartenberger and Miquel Crusafont i Pairó
Keywords: Can Ponsic 1; Miocene; Rodents; Valles-Penedes
 
  Abstract

    The rodents from the spanish locality of Can Ponsic 1 bring new data about some rodents species of the beginning of the Upper Miocene in South-West Europe. The criticims made by Mein and Freudenthal about the validity of the species Hispanomys thaleri from Can Llobateres are not justiíied. The study of the anatomy of the skull of Rotundomys from Can Ponsic 1 gives accurate information about the affinity of this genus with Cricetulus, and shows that the hypothesis, according to which Rotundomys is an ancestral form of the Arvicolids, is unlikely. The systematics of Heteroxerus and the phylogeny of the mio-pliocene Muscardinus species are also discussed. The Can Ponsic 1 locality is a little older than Can Llobateres.

      


  Article infos

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

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Leptacodon nascimentoi n,sp., un nouveau Nyctitheriidae (Mammalia,Lipotyphla) de l'Eocène inférieur de Silveirinha (Baixo Mondego, Portugal)
Carmen Estravis
Keywords: Eocene; Leptacodon; Lipotyphla; Mammals; Nyctitheriidae; Portugal; Silveirinha
 
  Abstract

    In this article is described a new species of Nyctitheriidae with primitive characters: Leptacodon nascimentoi n. sp. from the early Eocene of Silveirinha (Portugal). 


  Article infos

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

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Fallen in a dead ear: intralabyrinthine preservation of stapes in fossil artiodactyls
Maeva J. Orliac and Guillaume Billet
Keywords: allometry; bony labyrinth; inner ear; middle ear ossicles

doi: 10.18563/pv.40.1.e3
 
  Abstract

    The stapes is the last of the middle ear ossicle chain and the smallest bone of the mammalian skeleton. Because it rests on the membrane of the fenestra vestibuli during life, the stapes may often fall within the bony labyrinth cavity when soft structures decay after death. In this work, we highlight the unexpected role that the bony labyrinth plays in the preservation of the stapes. Systematic investigation of the bony labyrinth of 50 petrosal bones of extinct and extant artiodactyls led to the discovery of eight cases of “intralabyrinthine” stapes. Three dimensional reconstructions of these stapes allow documenting stapes morphology of four extinct artiodactyl taxa: Microstonyx erymanthius (Suidae), Elomeryx borbonicus (Hippopotamoidea), ?Helohyus plicodon (Helohyidae), and an undetermined Cainotheriidae; and four extant ones Choeropsis and Hippopotamus (Hippopotamidae), and Tayassu and Phacochoerus (Suoidea). ?Helohyus plicodon from the Middle Eocene documents the oldest stapes known for the order Artiodactyla. Morphological study and metric analyses of our sample of artiodactylan stapes show that stapes are likely to carry relevant phylogenetic characters/signal within artiodactyls, and a potential Euungulata signature. 


  Article infos

Published in Vol.40-1 (2016)

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S.I. Data
Table ronde sur les phosphorites du Quercy Montauban 15-16 Décembre 1972
Louis Thaler and Jean-Louis Hartenberger
Keywords: Quercy Phosphorites
 
  Abstract

    Voici une centaine d'années débutait sur les Causses du Quercy l'exploitation des phosphorites qui devait permettre d'amasser des collections de Vertébrés fossiles uniques au monde. Ces fossiles firent l'objet de nombreuses publications et les noms de Filhol, Gaudry, Schlosser, Stehlin, Teilhard de Chardin sont attachés à ces premières études.

    Après quelques années de prospection, les fouilles dans le Quercy ont repris en 1965, organisées par les laboratoires montpelliérains et parisiens. Ces premières recherches ont été aidées par le Centre National de la Recherche Scientifique qui a organisé une « table ronde» pour faire le point des premiers résultats obtenus. Ceux-ci ont été jugés suffisamment prometteurs pour que le C.N.R.S, ait décidé de poursuivre son effort par l'intermédiaire d'une Recherche Coopérative sur Programme.



      


  Article infos

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

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THE ANIMALS Systematische Zoologie
Leigh M. Van Valen
Keywords: Book review; Systematics
 
  Abstract

    Systematische Zoologie by A. REMANE, V. STORCH, and U. WELSCH.
    1986, Edition 3. Cloth and paperbound. Stuttgart and New York : Gustav Fischer Verlag.
    xvi + 698 pp. DM 86. (Geb.) & DM 72 (kart.). 


  Article infos

Published in Vol. 16, Fasc. 1 (1986)

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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
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. 


  Article infos

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

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Sur le remplissage des "poches à phosphorite" d'Aubrelong (commune de Bach, Lot)
Bernard Gèze
Keywords: Aubrelong; Quercy Phosphorites
 
  Abstract

    Abstract not available 


  Article infos

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

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Dilambodont Molars :a functional interpretation of their evolution
Percy M. Butler
Keywords: Convergent evolution; Dilambdodont; Molar function; Molar teeth
 
  Abstract

    In dilambdodont molars the primitive crest between paracone and metacone (centrocrista) is represented by a pair of crests that join the mesostyle (postparacrista, premetacrista). The cutting action of these crests against the crests of the hypoconid is described. Dilambdodonty is a derived adaptation for greater cutting efficiency. It has evolved several times and in more than one way. 


  Article infos

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

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Les mammifères Montiens de Hainin (Paléocène moyen de Belgique) Part III : Marsupiaux
Jean-Yves Crochet and Bernard Sigé
Keywords: Belgium; Marsupials; Paleobiogeography; Paleocene
 
  Abstract

    The oldest european marsupials are described from some specimens (isolated upper molars) recently found from the Hainin sediment (Middle Paleocene of Belgium). These fossils document a new species of the Peradectes genus. They give evidence of a much older occurrence of the marsupials in Europe than it was assumed. They allow us to postulate a didelphid dispersal from South America towards the western-holarctic area operating in two phases : the first one of the Peradectes genus at the end of the Cretaceous; the second one of the Didelphíni tribe at the end of the Paleocene. A central american crossing is likely for the first one,  whereas a transafrican way is tentatively argued for the second one. 


  Article infos

Published in Vol. 13, Fasc. 3 (1983)

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Cricetid and arvicolid rodents of the California wash local fauna, late Blancan of the san Pedro Valley, Arizona.
Cristiana Mezzabotta
Keywords: Arvicolidae; Blancan; Cenozoic; Cricetidae; Mammals
 
  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. 


  Article infos

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

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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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