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Page 9 of 19, showing 20 record(s) out of 367 total

Origins of avian reproduction: answers and questionsfrom dinosaurs.
David J. Varricchio Logo and Frankie D. Jackson
Published online: 15/12/2003

Keywords: Avian reproduction; clutch; dinosaurs; egg size; nests; oviducts; parental care

https://doi.org/10.18563/pv.32.2-4.149-169

  Abstract

    The reproductive biology of living birds differs dramatically from that of other extant vertebrates. Distinctive features common to most birds include a single ovary and oviduct, production of one egg at daily or greater intervals, incubation by brooding and extensive parental care. The prevalence of male parental care is most exceptional among living amniotes. A variety of hypotheses exist to explain the origin of avian reproduction. Central to these models are proposed transitions from a condition of no care to maternal, paternal or biparental care systems. These evolutionary models incorporate a number of features potentially preservable or inferable from the fossil record (integument, skeletal adaptations for flight, egg and clutch size, nest form, hatchling developmental stage, the number and function of oviducts, and the mode of egg incubation). Increasing availability of data on dinosaur reproduction provides a means of assessing these hypotheses with fossil evidence. We compare dinosaur data to a selection of models that emphasize maternal, paternal or biparental care. Despite some congruence with dinosaur features, no single model on the evolution of avian reproduction conforms fully to the fossil record, and the ancestral parental care system of birds remains ambiguous. Further investigation into dinosaur parental care, nest structures, clutch geometry, egg-pairing, eggshell porosity, and embryo identification may eventually resolve these issues.  


  PV article infos

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

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Les insectivores des phosphorites du Quercy
Jean-Yves Crochet
Published online: 15/11/1974

Keywords: Insectivores; Quercy Phosphorites

https://doi.org/10.18563/pv.6.1-2.109-159

  Abstract

    Many types of insectivores have been described from specimens found in the Quercy phosphorites. These remains very often were not dated because they came from old collections. Recent excavations have permitted the situation of Amphidozotherium cayluxi FILHOL in the late Eocene. Two new genera are descrlbed based on material both from the old collections (Cryplotopos nov. g.) and from that recently recovered (Darbonetus nov. g., beginning of the middle Oligocene). Their systematic positions are revised and comparisons with American faunas are made. Amphidozotherium is not a talpid, but an erinaceoid belonging to an indeterminate family. Saturninia gracilis STHELIN is classified among the Nyctitheriinae, Myxomygale antiqua FILHOL among the Urotrichini Talpinae, and the genus Geotypus POMEL among the Scaptonichini Talpinae. A new study of the talpids from Auvergne has been rendered necessary. During the late Eocene and Oligocene precise morphology relationships existed between certain insectivores of Europe and North America. 


  PV article infos

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

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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: 28/12/2001

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

https://doi.org/10.18563/pv.30.3-4.151-187

  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.

      


  PV article infos

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

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Les rongeurs de l'Eocène inférieur et moyen d'Europe Occidentale; Systématique, phylogénie, biochronologie et paléobiogéographie des niveaux-repères MP 7 à MP 14.
Gilles Escarguel Logo
Published online: 15/12/1999

Keywords: Biochronology; Early and Middle Eocene; Gliridae; Ischyromyidae; Mammalia; MP Scale; New Genus and Species; Palaeogeography; PHYLOGENY; Rodents; Theridomyidae; Western Europe

https://doi.org/10.18563/pv.28.2-4.89-351

  Abstract

    Fourteen distinct phyletical lineages which belong at least in three families: Ischyromyidae ALSTON, 1876, Gliridae THOMAS, 1896 and Theridomyidae ALSTON, 1876, have been identified after the study of more than 3600 rodent dental remains from about twenty Early and Middle Eocene european localities. A systematical and phylogenetical revision of these rodents has been achieved. Nearly all the specific and generic diagnosis are emended. Several new combinations and synonymies are proposed. Four new species and two new genera, Euromys nov. (Ailuravinae) and Hartenbergeromys nov. (Microparamyini), are named and described. Euromys nov. gen. is known by three distinctive ypresian (MP 7 to MP 10 european reference levels) chronospecies. This new lineage is thought to be the direct ancestor of Meldimys MICHAUX, 1968 and Ailuravus RUTIMEYER, 1891. A new species of the genus Plesiarctomys BRAVARD, 1850, Pl. lapicidinarum from Condé-en-Brie (MP 8-9 reference level), allows to relate the Plesiarctomys lineage to the Pseudoparamys MICHAUX, 1964 one. The taxa Sparnacomys HARTENBERGER, 1971, Pantrogna HARTENBERGER, 1971, and Corbarimys MARANDAT, 1989 are erected to genus rank; the last one is not thought to be an Ischyromyidae. A new chronospecies of Pantrogna, P. marandati nov. sp. from the locality of Prémontré (MP 10 reference level), is described. This lineage is at the origin of two others, namely Masillamys TOBIEN, 1954, including M. mattaueri (HARTENBERGER, 1975) nov. comb. (MP 10 reference level), and Hartenbergeromys nov. gen., known from MP 10 (H. hautefeuillei nov. sp.) and MP 11 (H. parvus TOBIEN, 1954) reference levels. The phylogenetical position of Hartenbergeromys nov. gen., at the origin of the european family Theridomyidae, is discussed. The systematical and phylogenetical status of two probable Paramyinae, "Paramys" woodi MICHAUX, 1964 and an unnamed genus and species, are discussed. New populations of the primitive Gliridae Eogliravus HARTENBERGER, 1971 and of the primitive Theridomyidae Protadelomys HARTENBERGER, 1968, are described and assigned to previously known species.

      


  PV article infos

Published in Vol. 28, Fasc. 2-4 (1999)

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Rongeurs du Miocène inférieur et moyen en Languedoc. Leur apport pour les correlations Marin-Continental et la Stratigraphie.
Jean-Pierre Aguilar
Published online: 31/03/1980

Keywords: Languedoc; Miocene; Rodents; Southern France

https://doi.org/10.18563/pv.9.6.155-203

  Abstract

    The rodents (Cricetidae, Gliridae, Sciuridae) found in lacustrine, brackish marine and karstic sediments of Miocene age in Languedoc, assign the position of the different localities in the scale of "niveaux repères" used by mammalogists. Some detailed stratigraphical studies bring several correlations between this continental biochronological scale and the marine scale ; the most important results are the Aquitanian age of the "niveaux repères" of Coderet and Paulhiac, the Burdigalian age of Laugnac, Estrepouy, Vieux-Collonges, La Romieu and Sansan and the Langhian or Lower Serravallian age of La Grive M. The correlations between the Tethys and the Central Paratethys for the Lower Neogene profit also of these results, since the locality of Neudorf Spalte 1, 2 (Czechoslovakia) is shown to be younger than Sansan (France). The paleontological study has also several geological inferences for the Miocene of Languedoc ; with the calibration of this Miocene, we know quite precisely that the Lower Miocene is chiefly a time lacustrine sedimentation, and also that the marine Miocene sedimentation ends early in the Miocene Period, in Langhian or lower Serravallian times. 


  PV article infos

Published in Vol. 09, Fasc. 6 (1980)

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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: 16/10/1972

Keywords: Footprints; South Africa; Stormberg; Trias

https://doi.org/10.18563/pv.5.ext

  Abstract

    Cet article explore les pistes fossiles de vertébrés du Stormberg (Trias, Afrique du Sud), révélant une diversité ichnologique inédite avec 64 ichnotypes classés en tridactyles, tétradactyles et pentadactyles. Les découvertes incluent des reptiles bipèdes comme Qemetrisauropus et Prototrisauropus, dont les empreintes suggèrent des adaptations évolutives vers la bipédie, ainsi que des pentadactyles géants comme Pentasauropus, annonçant les futurs sauropodes. L’étude combine ichnologie et restes osseux pour reconstituer des écosystèmes triasiques riches, où flore (fougères, conifères) et faune témoignent d’une transition écologique majeure avant l’essor des dinosaures. 


  PV article infos

Published in Vol. 5, Ext (1972)

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Enamel hypoplasia on rhinocerotoid teeth: Does CT-scan imaging detect the defects better than the naked eye?
Manon Hullot Logo and Pierre-Olivier Antoine Logo
Published online: 03/01/2022

Keywords: fossil teeth; method; micro-CT imaging; Rhinocerotoidea

https://doi.org/10.18563/pv.45.1.e2

  Abstract

    Micro-CT imaging is an increasingly popular method in paleontology giving access to internal structures with a high resolution and without destroying precious specimens. However, its potential for the study of hypoplasia defects has only recently been investigated. Here, we propose a preliminary study to test whether hypoplastic defects can be detected with micro-CT (μCT) scan and we assess the costs and benefits of using this method instead of naked eye. To do so, we studied 13 fossil rhinocerotid teeth bearing hypoplasia from Béon 1 (late early Miocene, Southwestern France) as positive control and 11 teeth of the amynodontid Cadurcotherium (Oligocene, Phosphorites du Quercy, Southwestern France), for which enamel was partly or totally obscured by cement. We showed that all macroscopically-spotted defects were retrieved on 3D reconstructions and selected virtual slices. We also detected additional defects using μCT scan compared to naked eye identification. The number of defects detected using μCT was greater in the Cadurcotherium dataset (paired-sample Wilcoxon test, p-value = 0.02724) but not for our control sample (paired-sample Wilcoxon test, p-value = 0.1171). Moreover, it allowed for measuring width and depth of the defects on virtual slices (sometimes linked to stress duration and severity, respectively), which we could not do macroscopically. As μCT imaging is both expensive and time consuming while not drastically improving the results, we recommend a moderate and thoughtful use of this method for hypoplasia investigations, restricted for instance to teeth for which enamel surface is obscured (presence of cement, uncomplete preparation, or unerupted germs). 


  PV article infos

Published in 45-1 (2022)

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S.I. Data
Difficulties with the origin of dinosaurs: a comment on the current debate
Matthew G. Baron Logo
Published online: 01/07/2020

Keywords: dinosaur anatomy; dinosaur evolution; Ornithoscelida; palaeobiogeography; Triassic Period

https://doi.org/10.18563/pv.43.1.e3

  Abstract

    The origin and early evolutionary history of the dinosaurs is a topic that has recently gone through a period of renewed interest and academic debate. For 130 years, one way of classifying the various dinosaur subgroups persisted as the accepted model, with increasing levels of research in the past quarter-century also providing evidence for the hypothesis that dinosaur origination occurred in the Southern Hemisphere, particularly in South America. It is, after all, from within the Late Triassic strata of countries like Argentina and Brazil that we get some of the very best early dinosaur specimens; many of these specimens are the earliest known representatives of some of the major dinosaur subgroups, such as the theropods and sauropodomorphs. However, some recent analyses have brought about a shift in terms of what is currently accepted and what is now disputed regarding the origin of dinosaurs – the Southern Hemisphere origination hypothesis was questioned (although this was based upon observations and not with quantitative analysis techniques), as has the shape of the dinosaur tree. Responses to the new hypothesis were numerous; many further supported a Southern Hemisphere point of origin. Whilst the interrelationships between the major dinosaur clades remains to be resolved, the current data does seem to comprehensively answer the question of where the dinosaurs first originated. However, it is arguable whether the current data that is being used in such palaeobiogeographical analyses is sufficient to provide an answer to the question of where specifically the dinosaur clade first appeared. This short communication urges a degree of caution about the current consensus and what steps may need to be taken to ensure that more meaningful results are produced in the future. 


  PV article infos

Published in Vol 43-1 (2020)

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An unusual cranial fossil of the giant lower Pliocene shrew (Paranourosorex gigas Rzebik-Kowalska, 1975) from Podlesice, Poland
David L. Harrison and Barbara Rzebik-Kowalska Logo
Published online: 29/10/1991

Keywords: Mammalia; Paranousorex gigas; Pliocene; Poland; Ruscinian; Soricidae

https://doi.org/10.18563/pv.21.1-2.95-102

  Abstract

    A well-preserved anterior cranium of Paranourosorex gigas RZEBIK-KOWALSKA, 1975 from Podlesice, Poland, provides additional knowledge of this rare shrew, including almost complete maxillary dentition. The systematic status of this species as a relative of recent Anourosorex MILNE-
    EDWARDS, 1870 is confirmed 


  PV article infos

Published in Vol. 21, Fasc. 1-2 (1991)

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Données et hypothèses sur la radiation initiale des rongeurs.
Jean-Louis Hartenberger
Published online: 01/10/1980

Keywords: Diversification scheme; Radiation; Rodents

https://doi.org/10.18563/pv.9.ext.285-302

  Abstract

    About the early radiation of Rodents, we have now from the early tertiary of Asia, a new fossil record, and we can do new interpretations. First the problem of the origin of Rodents is studied : considered as a sister group of Lagomorpha, it is possible to find their ancestors between the Mixodontia. Second the new facts about the origin of modern groups of Rodents are reviewed. A general scheme of this diversification can be proposed. 


  PV article infos

Published in Vol. 9, Ext (1980)

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Additions of the Geiseltal mammalian faunas, Middle Eocene: Didelphidae, Nyctitheriidae, Myrmecophagidae.
Gerhard Storch and Hartmut Haubold
Published online: 04/12/1989

Keywords: Edentata; Geiseltalian; German Democratic Republic; Lipotyphla; Marsupialia; MP 11-13

https://doi.org/10.18563/pv.19.3.95-114

  Abstract

    New and hitherto unpublished mammals from the stratigraphical levels Unterkohle, Untere Mittelkohle and Obere Mittelkohle of the Geiseltal near Halle, GDR, are described (= biochronological levels MP 11-13, Geiseltalian sensu Franzen & Haubold 1986a, b). The marsupial taxa Amphiperatherium aff. maximum (MP 12), A. goethei (MP 12), and Peratherium aff. monspeliense (MP 12 and 13) are recorded for the first time. A lectotype for Amphiperatherium giselense is designated, and the alleged primate Microtarsioides voigzi is assigned to Marsupialia, incertae sedis. A new insectivore species, Saturninia ceciliensis n. sp., is described (MP 13). The anteater Eurotamandua joresi is recorded for the first time outside its type locality, Grube Messel, FRG (MP 11). The present humerus and ulna display the autapomorphic features of the myrmecophagids. 


  PV article infos

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

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Les Entélodontes des phosphorites du quercy
Michel Brunet Logo
Published online: 15/11/1974

Keywords: Entelodontes; Quercy Phosphorites

https://doi.org/10.18563/pv.6.1-2.87-108

  Abstract

    The entelodonts of the Quercy phosphorites are essentially known from isolated teeth. The skull remains attributed to Entelodon magnum by Kowalewsky in 1876 and the type left mandible of Enteladon depereti RÉPELIN, 1918 do not belong to this family. From a morphologic point of view, the teeth from Quercy are quite comparable to those from the type localities of E. magnum and E. deguilhemi. In the absence of distinctive anatomical criteria between E. magnum (small species from the level of Ronzon) and E. deguilhemi (large species from the level of Villebramar) they are referred, according to their size, to one or the other of these two species. However, some of them are intermediate in size. Their existence speaks in favor of a close relationship between E. magnum and E. deguilhemi and confers a real stratigraphic interest to these entelodonts of Western Europe. Finally, some anatomical characters (notch on the mesial border of P4, presence of a paraconid joined to the metaconid, trigonid higher than talonid) considered until now as peculiar to the North American Archaeotherium and not yet cited in its European contemporary Entelodon have been brought to light on the teeth from Quercy.

      


  PV article infos

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

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Premières données sur les carnivores fissipèdes provenant des fouilles récentes dans le Quercy
Louis de Bonis Logo
Published online: 15/11/1974

Keywords: Carnivores; Quercy Phosphorites

https://doi.org/10.18563/pv.6.1-2.27-32

  Abstract

    Cet article présente les premières données sur les Carnivores fissipèdes des Phosphorites du Quercy, issues de fouilles récentes (1971-1972). Les fossiles se répartissent de l'Oligocène inférieur à supérieur. 


  PV article infos

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

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La région des phosphorites du Quercy
A. Cavaillé
Published online: 15/11/1974

Keywords: Quercy Phosphorites

https://doi.org/10.18563/pv.6.1-2.5-19

  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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Lower Paleogene crocodilians from Silveirinha, Portugal.
Miguel T. Antunes Logo
Published online: 15/10/2003

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

https://doi.org/10.18563/pv.32.1.1-26

  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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Introduction à l'oeuvre scientifique de Donald E. Russell, "gentleman paleontologist"
Marc Godinot Logo and Phillip D. Gingerich Logo
Published online: 16/12/1996

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

https://doi.org/10.18563/pv.25.2-4.63-74

  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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Pantolestidae nouveaux (Mammalia, Insectivora) de l'Eocène moyen de Bouxwiller (Alsace).
Jean-Jacques Jaeger Logo
Published online: 31/03/1970

Keywords: Bouxwiller; Insectivora; Mammalia; Middle Eocene; Pantolestidae

https://doi.org/10.18563/pv.3.3.63-82

  Abstract

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


  PV article infos

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

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A new and primitive species of Protophiomys (Rodentia, Hystricognathi) from the late middle Eocene of Djebel el Kébar, Central Tunisia
Laurent Marivaux Logo, El M. Essid Logo, Wissem Marzougui Logo, Hayet Khayati Ammar, Sylvain Adnet Logo, Bernard Marandat, Gilles Merzeraud, Rodolphe Tabuce Logo and Monique Vianey-Liaud Logo
Published online: 02/06/2014

Keywords: Adaptive radiation; Bartonian; Dental morphology; North Africa; Paleobiogeography

https://doi.org/10.18563/pv.38.1.e2

  Abstract

    Based on fossil discoveries and phylogenetic studies, an Eocene Asian origin for hystricognathous rodents and anthropoid primates has gained strong support in recent years. The two groups then invaded both Africa and South America, which promoted their evolutionary success. However, the fossil record has so far failed to constrain the nature and precise timing of these pivotal dispersal events. In Africa, given the apparent absence of hystricognaths and anthropoids in early to early middle Eocene localities, it is suggested that these mammal groups dispersed from Asia to Africa sometime during the middle Eocene. In this paper, we report the discovery of several isolated teeth of a rodent from a new vertebrate locality situated in central Tunisia (Djebel el Kébar, KEB-1), dating from the late middle Eocene (Bartonian, ~39.5 Myr). These fossils document a diminutive new species of Protophiomys (P. tunisiensis nov. sp.), a basal genus of hystricognathous rodents which is well known from several North African mammalian-bearing localities of the end of the Eocene. The teeth of P. tunisiensis display a suite of anatomical details comparable with those observed in the other species of the genus, but with a lesser degree of development. Such an apparent primitive evolutionary stage is corroborated by the greater antiquity of this Tunisian species. P. tunisiensis nov. sp. is so far the most ancient representative of hystricognaths in Africa. However, it can be expected that hystricognaths were already present on that landmass given the new data on early caviomorphs recently reported from South America (at ~41 Myr). The arrival of hystricognaths in Africa from South Asia certainly predates the depositional period of the Kébar sediments, but perhaps not by much time. 


  PV article infos

Published in Vol.38-1 (2014)

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A new study of the anthracotheres (Mammalia, Artiodactyla) from pondaung formation, Myanmar: systematics implications
Aung N. Soe
Published online: 16/12/2008

Keywords: Anthracohyus; Anthracokeryx; Anthracotherium; Pondaung Formation; sexual dimorphism; Siamotherium; South East Asia; taxonomy

https://doi.org/10.18563/pv.36.1-4.89-157

  Abstract

    Anthracotheres from the Pondaung Formation, Myanmar, are considered as one of the most primitive artiodactyl groups and they represent the oldest known record in the world. Thus, the understanding of this group has numerous implications for evolutionary biology and biochronological correlations. However, the systematlcs of these mammals has been interpreted in different ways, and the main debate focuses on the number of taxa represented in the Pondaung Formation. The revised taxonomy proposed here is mainly based on the relative development of the upper molar W-shaped ectoloph, system of crests and stylar cusps, and on body size. On the basis of these characters, they are classified into four genera including six different species. Two well-known genera, Anthracotherium and Anthracokeryx, are validated and more precisely diagnosed. Anthracokeryx possesses a better developed W-shaped ectoloph, system of crests and stylar cusps than Anthracotherium, which displays notable differences with the more derived representatives of this genus. Both of these Pondaung genera show evidence for sexual dimorphism. However, the incompleteness of fossil material fueled a debate concerning the status of two additional Pondaung anthracotheres, Siamotherium and Anthracohyus. The latter genus is of uncertain affinities, but it has been considered as a hippopotamid ancestor. Despite new material attributed to these two forms, additional discoveries are still required to establish their taxonomic status. The hypothesis that Southeast Asia was the centre of origin of Anthracotheriidae is supported by the retention of numerous primitive dental characters in these taxa and by the antiquity of the Pondaung Formation, to which an age of 37 My is now generally accepted. 


  PV article infos

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

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Fossil snakes from the Palaeocene of São José de Itaboraí, Brazil Part III. Ungaliophiinae, Booids incertae sedis, and Caenophidia. Summary, update and discussion of the snake fauna from the locality
Jean-Claude Rage Logo
Published online: 16/12/2008

Keywords: booid-grade incertae sedis; Brazil; Caenophidia; New taxa; Palaeocene; Russellophiidae; Snakes; tropidophiids; Ungaliophiinae

https://doi.org/10.18563/pv.36.1-4.37-73

  Abstract

    Aside from Madtsoiidae, anilioids, and Boidae that were studied previously, the middle Palaeocene of ltaborai (BraziI) has produced Ungaliophiinae ("tropidophiids"), booid-grade snakes incertae sedis, and a possible Russellophiidae (Caenophidia) that are described in the present article. This article is the third and final report on the snakes from the locality. The Ungaliophiinae (Paraungaliophis pricei gen. et sp. nov.) are rare whereas the booid-grade snakes incertae sedis (ltaboraiophis depressus gen. et sp. nov., Paulacoutophis perplexus gen. et sp. nov.) are more frequent. A single vertebra is referred to the Russellophiidae (Caenophidia) with reservation. An update of the whole fauna of snakes from ltaborai is provided. Hechtophis austrinus that was tentatively referred to the erycine Boidae is now regarded as a Boidae incertae sedis. Most snakes from Itaborai are known only from the locality. Astonishingly, only the ailioids Coniophis cf. C. precedens gives possible evidence of interchanges between South and North America. The fauna of snakes from Itaborai, as well as the other Palaeocene faunas of snakes from South America are distinct from those of the Cretaceous and the Eocene of South America; they appear to be more different from the Cretaceous faunas than from those of the Eocene. The fauna from Itaborai is the richest and most diverse assemblage of snakes from the Palaeocene worldwide; it shares only a few taxa with other Palaeocene localities. 


  PV article infos

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

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