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Page 2 of 19, showing 20 record(s) out of 369 total

First report of Cylindracanthus (Osteichthyes) from the Eocene of India
Pankal Kumar, Rajeev Patnaik Logo, Deepak Choudhary Logo, Rohit Kumar Logo and Wasim Abass Wazir Logo
Published online: 25/03/2024

Keywords: Cylindracanthus; Eocene; histology; rostrum; Umarsar mine.

https://doi.org/10.18563/pv.47.1.e2

  Abstract

    Fossils of the endangered sturgeons and peddlefishes are widely distributed. We here report for the first time the presence of one of the extinct osteichthyes genus Cylindracanthus (Liedy 1856a) from the Early Eocene lignite-bearing successions of the Kutch Basin, India. The present well preserved rostrum is characterised by numerous wedge-shaped components encircling the central canal that runs along its length, paired at the base and each wedge contributing to the formation of a ridge. The rostrum lacks teeth. The present find extends the palaeobiogeographical distribution of Cylindracanthus considerably and supports its Eocene age as dental remnants preserved in Cylindracanthus sp. shows a decrease in remanent dentition and tooth bases from the Cretaceous to the Eocene. Cylindracanthus is an useful palaeoenvironmental indicator as it has been found associated typically with deposits of nearshore marine environments. 


  PV article infos

Published in 47-1 (2024)

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Late Campanian theropod trackways from Porvenir de Jalpa, Coahuila, Mexico
Héctor E. Rivera-Sylva Logo, Eberhard Frey Logo, Christian Meyer, Anne S. Schulp Logo, Wolfgang . Stinnesbeck Logo and Valentin Vanhecke
Published online: 29/11/2017

Keywords: Dinosaur tracks; Late Cretaceous; Mexico.; Tetanura; Theropod

https://doi.org/10.18563/pv.41.2.e1

  Abstract

    Confident attribution of bipedal tridactyl dinosaur tracks to theropods or ornithopods can be challenging. Here we describe trackways produced by tetanuran dinosaurs, previously attributed to hadrosaurs, from Coahuila State, northeastern Mexico. Multiple trackways headed in the same direction suggest gregarious behaviour in these late Campanian theropods.  


  PV article infos

Published in Vol 41-2 (2018)

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Nouvelles données sur les mammifères du Thanétien et de l'Yprésien du bassin d'Ouarzazate (Maroc) et leur contexte stratigraphique.
Emmanuel Gheerbrant Logo, Jean Sudre, Sevket Sen Logo, Claude Abrial, Bernard Marandat, Bernard Sigé and Monique Vianey-Liaud Logo
Published online: 15/12/1998

Keywords: early Paleogene; magnetostratigraphy; Mammals; Morocco; North Africa; Ouarzazatz basin; Systematics

https://doi.org/10.18563/pv.27.3-4.155-202

  Abstract

    New faunal and stratigraphical data on the vertebrates localities from the early Paleogene of the Ouarzazate Basin (Adrar Mgorn 1, Adrar Mgorn 1 bis et N'Tagourt 2), Morocco, are presented. A magnetostratigraphical study, the first for such early Paleogene Arabo-African mammal localities, and the discovery of probable remains of the nannofossil Discoaster support the Thanetian age of the Adrar Mgorn 1 site. The magnetostratigraphy suggests a slightly later age than was thought for the Paleogene formations of the local series of Tinerhir and for the vertebrate localities: late or latest Thanetian for Adrar Mgorn 1 and Adrar Mgorn 1 bis, middle Ypresian for N'Tagourt 2. It also indicates a lower position of the KT boundary in the series. Two tons of matrix recovered in the vertebrate sites have vielded new data on the micromammals. A damaged lower molar from N'Tagourt 2 is referable to Khamsaconus bulbosus  and supports the proboscidean affinities of this species and especially possible relationships with bunolophodont taxa such as elephantiforms. A lower molar from Adrar Mgorn 1 bis belongs to a new form which can be identified as a plesiadapiform or an euprimate close to Altiatlasius koulchii though significantly larger. A new material from Adrar Mgorn 1 illustrates a new dilambdodont adapisoriculid species which is referable to Garatherium : ?Garatherium todrae n. sp. Another species referred to Garatherium is known in the locality (?Garatherium n. sp.). Garatherium is a new lineage from the Ouarzazate basin which crosses the Paleocene-Eocene boundary together with Palaeoryctes, Didelphodontinae gen. and sp. 2, Todralestes, and Afrodon, and it is the first Paleocene-Eocene lineage identified outside of this basin (Garatheríum is based on a species from El Kohol, Algeria). Among the Paleocene-Eocene lineages from the Ouarzazate basin, it should be also mentioned a new possible carnassial form (carnivoran or creodont; Adrar Mgorn 1), and an upper molar of Cimolestes cf. incisus (Adrar Mgorn 1 bis). The upper molar THR 168 previously reported as from an indeterminate didelphodontine is here identified as the M1/ of Afrodon chleuhi. The micromammal faunas from the Ouarzazate basin are positioned in the global chronological framework of the mammal localities from the Paleogene of the Arabo-African domain. 


  PV article infos

Published in Vol. 27, Fasc. 3-4 (1998)

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La morphologie dentaire des Thalattosuchia (Crocodylia, Mesosuchia).
Patrick Vignaud Logo
Published online: 15/12/1997

Keywords: Dental morphology; Dental types; feeding habits.; Jurassic; Metriorhynchidae; Systematics; Teleosauridae; Thalattosuchia

https://doi.org/10.18563/pv.26.1-4.35-59

  Abstract

    The tooth morphology of the Thalattosuchia (marine crocodilians from the Jurassic and the Early Cretaceous) is analysed. The Callovian from Poitou and the Kimmeridgian from Quercy have yielded many remains of Metriorhynchus, Steneosaurus and Machimosaurus. These remains allow us to study the variations of tooth morphology during ontogenic growth, tooth replacement and the location of the teeth. We have defined different tooth types for these genera. In Metriorhynchus, the two tooth types defined do not coincide with the two groups recognized in the Callovian (broad-skulled and narrow-skulled metriorhynchids) but reflect the prey preferences of these forms. In Steneosaurus and Machimosaurus the five tooth types deñned are in agreement with the main taxa known from the Bathonian to the Early Cretaceous. This study allows to precise the function and the prey preference of the Thalattosuchia during the Jurassic and the Early Cretaceous.

      


  PV article infos

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

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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: 15/10/2006

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

https://doi.org/10.18563/pv.34.e14

  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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Reconstruction of the cervical skeleton posture of the recently-extinct litoptern mammal Macrauchenia patachonica Owen, 1838
R. E. Blanco, Lara Yorio Logo and Felipe Montenegro Logo
Published online: 02/05/2023

Keywords: biomechanics; cervical posture; functional anatomy; Litopterna; Macrauchenia

https://doi.org/10.18563/pv.46.1.e1

  Abstract

    Macrauchenia patachonica was among the largest litopterns. It had a long neck with elongated cervical vertebrae, unique among endemic South American ungulates. We calculated the pattern of stress in the joints between the vertebral centra along the neck of the recently-extinct litoptern mammal M. patachonica for various hypothetical neck postures to determine which one is optimal. We also determined the zygapophyseal alignment positions for the neck, assuming a wide range of values for the thickness of the intervertebral discs. We concluded that a vertical posture is the one that best meets the requirements of nearly constant stress. This upright posture was probably a frequently adopted posture by M. patachonica while feeding or standing. It is also possible that occasionally it could adopt a gerenuk-like posture. In almost any other position, the standard deviations of stress values (SD) divided by mean stress (MS) have values between 0.4 and 0.5. Since it was a mixed feeder, M. patachonica probably used different postures to reach resources at different heights. However, an almost horizontal posture was required for the optimal articulation of the neck vertebrae. It probably represents the posture during fast locomotion, as suggested in a previous biomechanical study of locomotion. 


  PV article infos

Published in 46-1 (2023)

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La plus ancienne faune de mammifères du Quercy : Le Bretou
Jean-Louis Hartenberger, Bernard Sigé and Jean Sudre
Published online: 01/12/1974

Keywords: Le Bretou; Quercy Phosphorites

https://doi.org/10.18563/pv.6.3-4.177-196

  Abstract

    Redécouvertes en 1968 dans le bois du Bretou, les deux poches à phosphorites qui ont livré cette faune sont parmi les plus méridionales du plateau quercynois. De faible profondeur, huit mètres, les cavités sont de petite taille et font partie d'un complexe de sept fissures réparties dans les bois du Bretou. Les autres trous n'ont livré aucun fossile, soit parce qu'ils avaient été intégralement vidés de leur sédiment, soit que des venues d'eau en interdisent l'accès.
    Dans les deux poches fossilifères, proches de quelques mètres, le sédiment que l'on rencontre en placage sur les parois présente un aspect particulier. Il s'agit en effet d'une brèche très indurée, où la calcite domine, et contenant assez peu de sédiments sidérolithiques. Les ossements contenus dans cette brèche sont assez nombreux, très souvent brisés. Les dents isolées y sont relativement rares. Exploitées séparément, les deux poches ont livré des faunes identiques, aucune différence chronologique ne pouvant être décelée entre elles. Les formes rencontrées dans une seule des cavités sont rares mais la poche la plus riche est celle dénommée Le Bretou 2.
    L'intérêt de la faune récoltée réside dans son ancienneté. On sait en effet que H.G. Stehlin avait signalé dans les collections du Quercy des restes attribuables à Lophiodon lautricense, mais la provenance exacte de ces fossiles reste inconnue. Au Bretou si nous n'avons pas rencontré à ce jour le Lophiodon, il n'en demeure pas moins que l'âge de la faune récoltée doit être proche de celui de la faune de Robiac. 


  PV article infos

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

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The Quaternary avifauna of Crete, Greece.
Peter D. Weesie
Published online: 01/09/1988

Keywords: Avifauna; Crete; Quaternary; Systematics

https://doi.org/10.18563/pv.18.1.1-94

  Abstract

    Pleistocene bird fossils have been studied from nine localities on Crete. Part of this material was described earlier by the author (Weesie, 1982) and will not be treated here in extenso, the results will be incorporated. More than one third of the over 10,000 fossil bird bones available could be identified ; they were found to represent at least 65 bird species. The following species of the Pleistocene Cretan avifauna are new to the fauna of Crete : Branta ruficollis, Haliaeetus albicilla, Gyps melitensis, Aquila chrysaetos simurgh n. ssp., Ketupa zeylomensis, Aegolius funereus, Dendrocopos leucotos, Zoothera dauma, Turdus iliacus and Pyrrhula pyrrhula. The Pleistocene Cretan avifauna differs less from comparable mainland avifaunas than (fossil) avifaunas from oceanic islands do. Still, the Pleistocene Cretan avifauna has two qualities that are characteristic of island avifaunas : the almost complete absence of a group of birds (the Galliformes) and the presence of two endemic (sub)species : the giant eagle Aquila chrysaetos simurgh n. ssp. and the long-legged owl Athene cretensis (Weesie, 1982). The new subspecies is described in the present study.
    These endemic birds of prey were found in association with their supposedly principal prey species (now extinct as well) : endemic mice for the owl and endemic deer for the eagle. Endemic mammals have been found in association with endemic birds of prey on many islands, not only in the Mediterranean. There is evidence that the size of endemic birds of prey becomes optimally adapted to their feeding on certain endemic mammals, especially rodents. Another characteristic of the Pleistocene Cretan avifauna is the great number of species of birds of prey. This appears to be a common characteristic of fossil avifaunas from caves on Mediterranean islands as well as from caves on the European mainland. However, we think that ecological conditions on Pleistocene Crete (especially the abundant presence of mice) helped to account for the high representation of birds of prey. Furthemore, the fossil avifauna enables us to draw some conclusions about the climate and vegetation on Pleistocene Crete : it is concluded that the climate was cooler than today and that Crete was largely covered with forests. Finally, the reasons for the extinction or disappearance from Crete of some bird species of the Pleistocene Cretan avifauna are discussed. 


  PV article infos

Published in Vol. 18, Fasc. 1 (1988)

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Otolithes de poissons du Pliocène inférieur de Papiol, près de Barcelone.
Dirk Nolf, Ramon Mané and Agusti Lopez
Published online: 15/09/1998

Keywords: Catalonia; otoliths; Pliocene; Spain; teleosts

https://doi.org/10.18563/pv.27.1-2.1-17

  Abstract

    The Zanclian marls from Papiol provided otoliths belonging to 53 teleost taxa; nine of those are new for the Mediterranean Pliocene. The association reflects a bathymetry between 150 and 350 m, but it is likely that such depths only existed at the initial stage of flooding of the Llobregat bay. A compilation of the available data for the whole Mediterranean realm at Zanclian time provided a list of 163 taxa, of which 105 could be identified at species level. This last group provides the most useful data for evaluating the composition and affinities of the Mediterranean Zanclian fauna, which appears to be significantly different from the Recent Mediterranean fauna. The Zanclian fauna counts 68 % of Recent species: 12,5 % were already represented in the Mediterranean Miocene, 37 % appeared there at the Zanclian, and 18 % are extra-Mediterranean today. This last group is essentially composed by oceanic fishes, living in the warm parts of the Atlantic and Indo-Pacific Oceans. It is evident that a non neglectable number of Recent species only penetrated very recently in the Mediterranean, which stresses the differences between the more oceanic Zanclian Mediterranean fauna and the present one.


      


  PV article infos

Published in Vol. 27, Fasc. 1-2 (1998)

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Preliminary evolution of paleosols and implications for interpreting vertebrate fossil assemblages, Kuldana formation, Northern Pakistan
Andres Aslan and J. G. M. Thewissen Logo
Published online: 16/12/1996

Keywords: Eocene; Kuldana Formation; Pakistan; Paleosols; Pedogenic Carbonate; taphonomy; Time Averaging; Vertebrate Fossils

https://doi.org/10.18563/pv.25.2-4.261-277

  Abstract

    Paleosols and the taphonomy of vertebrate fossils in the Eocene Kuldana Formation of northern Pakistan provide important information on the preservation and time-averaging of fossil assemblages. Morphologic, mineralogic, and chemical data as well as comparisons with Quaternary soils suggest that Kuldana paleosols formed under generally dry and oxidizing conditions over time intervals of less than 100 000 years and perhaps as short as 1000 years. The distribution of carbonate in Kuldana paleosols further indicates that the upper half of the profiles were acidic whereas the lower halves were alkaline. Vertebrate fossils are rare in Kuldana paleosols and occur primarily in well-cemented sandstones and conglomerates with abundant micritic and iron-stained nodules that were reworked from floodplain soils. The scarcity of vertebrate remains in Kuldana paleosols probably reflects a combination of acidic, dry, and oxidizing conditions in the upper half of the profiles and rapid floodplain sedimentation. Comparisons between the taphonomic characteristics of Kuldana channel fossil assemblages and bone accumulations in modem rivers provide a basis for estimating the length of time represented by Kuldana fossils from several important localities. Vertebrate fossil assemblages from Barbora Banda are characterized by a low-diversity paleofauna, partially articulated skeletons, and bones that are sorted by size and shape. Comparison with bone accumulations in modern rivers suggests that the fossils from Barbora Banda accumulated in 1 to 10 years. Vertebrate fossils from the Lower Kuldana in the Kala Chitta Hills region, typified by locality H-GSP 62, are characterized by a high-diversity paleofauna and generally random and unsorted fossil bone distributions, which suggest that the fossils from these localities represent longer time intervals than the Barbora Banda fossils. Based on the time estimates for Kuldana paleosol development, fossil assemblages in Kuldana channel deposits in the Kala Chitta Hills region probably represent time intervals of about 1000 years. 


  PV article infos

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

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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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Rodent paleocommunities from the Oligocene of Ulantatal (Inner Mongolia, China)
Helder Gomes Rodrigues Logo, Laurent Marivaux Logo and Monique Vianey-Liaud Logo
Published online: 10/06/2014

Keywords: late Paleogene; Mammalia; Mongolian Plateau; Rodentia; Systematics

https://doi.org/10.18563/pv.38.1.e3

  Abstract

    The Oligocene deposits of the Ulantatal area in Inner Mongolia (China) contain among the richest mammalian faunas from Asia. To date, only some parts of the rodent faunas have been described. Here, we propose to review the rodent faunal lists for each site, including the description of a few new rodent specimens. We describe three additional rodent species: the Cylindrodontidae Anomoemys lohiculus, the Eomyidae Asianeomys sp., and the Dipodidae Litodonomys huangheensis. This study allows us to constrain the stratigraphic range of Anomoemys lohiculus, which ranged from the late Early Oligocene to the early Late Oligocene in this area. Asianeomys sp. and Litodonomys huangheensis are dated from the latest Oligocene. These Oligocene deposits consist now of more than 70 species of mammals if we include the fauna from Kekeamu. This latter corresponds to the basal part of the Ulantatal Formation and could be dated biochronologically from the earliest Oligocene. When compared to the faunas from the Valley of Lakes in Central Mongolia, the Ulantatal faunas present a great majority of rodents, and this difference can be partly explained by sampling and description biases regarding macro-mammals. This study also shows that variations existed between Inner and Central Mongolia, especially regarding the composition of the rodent paleocommunities. However, the assessment of their evolutionary history in this part of Asia with respect to the important climate and environment changes, require further precisions and more material than current data allow. 


  PV article infos

Published in Vol.38-1 (2014)

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Lissamphibians from Dams (Quercy, SW France): Taxonomic identification and evolution across the Eocene-Oligocene transition
Alfred Lemierre Logo and Maeva J. Orliac Logo
Published online: 25/06/2025

Keywords: Eocene-Oligocene; Grande Coupure; Lissamphibia; Quercy Phosphorites

https://doi.org/10.18563/pv.48.1.e3

  Abstract

    The locality of Dams (Quercy, southwestern France) has yielded two fossil assemblages, one from the late Eocene and another from the early Oligocene, making it one of the few localities with infillings across the Eocene-Oligocene transition. At least 24 taxa (13 mammals, 11 snakes) have been identified in this locality. Study of the lissamphibian remains from Dams yields an Eocene and an Oligocene assemblage, with a total of eight taxa. The Eocene assemblage includes two unnamed salamandrine species, one unnamed pelobatid species and one pyxicephalid species (Thaumastosaurus). The Oligocene assemblage includes two unnamed pleurodeline species, one salamandrine species (Salamandra sansaniensis) and an unnamed pelobatid species. Among the eight taxa from Dams, one Eocene salamandrine and one Oligocene pleurodeline are identified for the first time in the Quercy. A review of the lissamphibians from the Quercy area identifies eleven taxa for the Late Eocene (MP19) and eight taxa for Early Oligocene (MP22), with a major turnover at the Eocene-Oligocene transition. This turnover occurs in a time of major climatic changes, with a significant decrease in temperature and precipitation and concurrent increase in seasonality in Europe, likely affecting specialized taxa.
      


  PV article infos

Published in 48-1 (2025)

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Study of the Turolian hipparions of the lower Axios valley (Macedonia, Greece). 4. Localities of Dytiko.
George D. Koufos
Published online: 15/12/1988

Keywords: Equidae; Greece; Hipparion; Lower Axios Valley; Macedonia; Mammalia; Turolian

https://doi.org/10.18563/pv.18.4.187-239

  Abstract

    The hipparions from the Dytiko localities of the lower Axios valley (Macedonia, Greece) are studied. The material comes from three localities Dytiko-l, 2, 3 (DTK, DIT, DKO), which are situated near the village of Dytiko, about 60 km northwest to Thessaloniki. Three species have been determined, the medium-sized H. mediterraneum, the small-sized H. matthewi and the very small-sized H. periafricanum. The determined Hipparion species, their morphological characters and their comparison with the other Axios valley material indicate a Late Turolian age for the Dytiko localities. 


  PV article infos

Published in Vol. 18, Fasc. 4 (1988)

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

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

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

  Abstract

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


  PV article infos

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

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Rongeurs du Miocène supérieur de Chorora (Ethiopie): Cricetidae, Rhizomyidae,Phiomyidae, Thryonomyidae,Sciuridae.
Denis Geraads Logo
Published online: 15/12/1998

Keywords: cricetids; Ethiopia; phiomyids; rhizomyids; Rodentia; sciurids; thryonomyids; Upper Miocene

https://doi.org/10.18563/pv.27.3-4.203-216

  Abstract

    Besides Dendromurids and Murids, the Chorora Rodents include 7 taxa, two of which are new. Afaromys nov. gen. is a Cricetodontine with very complicated lower molars, certainly isolated for a long time from Eurasian species. A Paraphiomys, with tetralophodont upper molars, is also quite different from other East African species, and its roots should probably he searched in the middle Miocene. Other taxa are less original, and more similar to the South Asiatic ones. 


  PV article infos

Published in Vol. 27, Fasc. 3-4 (1998)

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Evolution et extinction des reptiles marins au cours du Mésozoïque.
Nathalie Bardet Logo
Published online: 02/10/1995

Keywords: Crocodiles; evolution; Extinctions; faunal assemblages; Helveticosaurs; Hupehsuchians; Ichthyoaurs; lizards; Marine Reptiles; Mesozoic; Nothosaurs; Pachypleurosaurs; Placodonts; Plesiosaurs; Snakes; Thalattosaurs; Turnovers; Turtles

https://doi.org/10.18563/pv.24.3-4.177-283

  Abstract

    An interpretation of the marine reptile fossil record, based on the existing litterature and complemented by the review of ancient collections and the study of new material, permits a better understanding of Mesozoic marine ecosystems. An inventory of the marine reptiles known from the Lower Triassic to the Paleocene is presented: 46 families, about 200 genera and 400 species have been recorded. This data base includes commentaries about systematics, stratigraphical ranges and geographical distribution of taxa. Marine reptiles include a mosaic of not necessarily closely related groups: ichthyosaurs, thalattosaurs, hupehsuchians, pachypleurosaurs, placodonts, nothosaurs, plesiosaurs, pliosaurs but also crocodiles, lizards, snakes, turtles. The diversity studies reveal that the fossil record of marine reptiles has been punctuated by two mass extinctions, during the Middle-Upper Triassic transition and at the Cretaceous-Tertiary boundary. The Jurassic-Cretaceous and Cenomanian-Turonian boundaries (the latter marked by the disappearance of ichthyosaurs) are potential crisis periods, but current data are not sufficient to reach conclusions. The Ladinian-Carnian transition is characterized by the disappearance of 64 % of families and affects essentially coastal forms. This extinction coincides with an important regressive phase. During the Upper Triassic, a faunal reorganisation within marine reptiles leads to the progressive disappearance of near-shore forms and to the development of pelagic groups. During the Maastrichtian-Danian crisis, 36% of families died out. Large-sized pelagic forms such as mosasaurs and elasmosaurs were the most affected and their extinction seems to have been rather sudden. On the other hand, pliosaurs and protostegid turtles became extinct, but were already declining. The survivors were near-shore forms such as crocodiles, snakes and some turtles and they may have taken refuge in freshwater environments. A break in the food chain based on phytoplankton is proposed as an extinction scenario for pelagic forms.

      


  PV article infos

Published in Vol. 24, Fasc. 3-4 (1995)

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Un Haplobunodontidae nouveau Hallebune krumbegeli nov.gen. nov.sp. (Artiodactyla, Mammalia) dans l'Eocène moyen du Geiseltal près Halle (Sachsen-Anhalt, Allemagne)
Jorg Erfurt and Jean Sudre
Published online: 14/06/1995

Keywords: Artiodactyla; Geiseltal; Germany; Mammal; Middle Eocene; new gen.; new sp.

https://doi.org/10.18563/pv.24.1-2.85-99

  Abstract

    A new genus and species of haplobunodontid artiodactyl, Hallebune krumbiegeli nov. gen. nov. sp., is described from the middle Eocene Geiseltal Fauna (Saxon-Anhalt, Germany). Its stratigraphic range is restricted to the MP 13 ("obere Mittelkohle") of the Geiseltalian. The material consists of seven fragments, representing both upper and lower jaws. It is indicated, that H. krumbiegeli was a small bunodont herbivore. The size and primitive character of the teeth suggest that the genus possibly is directly derived from Diacodexeidae.The new material forms the basis for reinterpreting the haplobunodontid phylogeny. 


  PV article infos

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

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Diversity among north african dinosaur eggshells.
Monique Vianey-Liaud Logo and Géraldine Garcia Logo
Published online: 15/12/2003

Keywords: Cretaceous; Dinosaurs diversity; Eggshells; Maastrichtian; Morocco; North Africa; taxonomy

https://doi.org/10.18563/pv.32.2-4.171-188

  Abstract

    Until the discovery of dinosaur eggshells locality in the Oukdiksou syncline, (Middle Atlas, Morocco) in 1999 (Garcia et al. this volume) the maastrichtian reptiles faunas were unknown in North Africa. Additional material from Achlouj-2 allows us to describe five oospecies, belonging to four oofamilies. The Megaloolithidae is recorded by Megaloolithus maghrebiellsis Garcia el al. and Pseudomegaloolithus atlasi oogen. novo oospec. nov. Tipoolithus achloujensis Garcia et al. is questionably considered as a Subtiliolithidae. A relatively small Elongatoloolithidae is represented by Rodolphoolithus arioul oogen. nov. oospec. nov. A thin Prismatoolithidae is described as a new oospecies of ? Pseudogeckoolithus Vianey-Liaud & Lopez-Martinez, 1997: P. tirboulensis. The diversity of these oospecies indicates that the dinosaur fauna comprises at least five dinosaur oospecies, with perhaps one sauropod and three theropods. 


  PV article infos

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

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Observations sur des remaniements structuraux post-mortem dans des dents de mammifères fossiles provenant des phosphorites du Quercy
Jean-Albert Remy
Published online: 01/12/1974

Keywords: Quercy Phosphorites; rearrangements; Teeth

https://doi.org/10.18563/pv.6.3-4.163-176

  Abstract

    Deux types de remaniements post mortem me paraissent caractéristiques de l'état de conservation des dents de mammifères fossiles dans les Phosphorites du Quercy :

    1) Des destructions localisées d'origine biologique, sous forme de galeries de morphologie très variable creusées dans la dentine et le cément, et impliquant sans doute la participation de différents types de micro-organismes. Ces altérations se sont développées peu de temps après la mort, avant la fossilísation proprement dite et se sont rapidement arrêtées après l'enfouissement dans le sédiment phosphaté.

    2) Des perturbations dans les structures de la dentine liées aux variations locales de minéralisation, provoquées par une imprégnation diffuse des zones les moins calcifiées par divers minéraux et probablement surtout de l`apatite. 


  PV article infos

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

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