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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, El M. Essid, Wissem Marzougui, Hayet Khayati Ammar, Sylvain Adnet, Bernard Marandat, Gilles Merzeraud, Rodolphe Tabuce and Monique Vianey-Liaud
Keywords: Adaptive radiation; Bartonian; Dental morphology; North Africa; Paleobiogeography

doi: 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. 


  Article infos

Published in Vol.38-1 (2014)

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Palaeotis weigelti restudied : a small middle Eocene Ostrich (Aves : Struthioniformes)
Peter Houde and Hartmut Haubold
Keywords: Aves; Central Europe; Middle Eocene; Palaeotis; Struthioniformes
 
  Abstract

    Palaeotis weigelti, from the Middle Eocene of central Europe, is a flightless, paleognathous bird. It appears to be a member of the ostrich lineage on the basis of trivial derived characters. It is a very primitive ratite, however, and does not possess any of the highly specialized cursorial adaptations that characterize the modern steppe -and savanna- dwelling ostriches. 


  Article infos

Published in Vol. 17, Fasc. 2 (1987)

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New remains of the giant bird Gargantuavis philoinos from the Late Cretaceous of Provence (south-eastern France)
Eric Buffetaut, Delphine Angst, Patrick Mechin and Annie Mechin-Salessy
Keywords: Aves; Gargantuavis; Late Cretaceous; Pelvis; South-eastern France

doi: 10.18563/pv.39.2.e3
 
  Abstract


    Two incomplete pelves of the giant bird Gargantuavis philoinos are described from Late Cretaceous deposits at Fox-Amphoux (Var, south-eastern France). They consist of synsacra with attached parts of the ilia. One of them has undergone considerable dorsoventral compression, which makes it very similar in appearance to the holotype pelvis of Gargantuavis philoinos from Campagne-sur-Aude (Aude, southern France). The second specimen has suffered some lateral distortion but is uncrushed dorsoventrally. Because of this, its avians characters (including an arched synsacrum and widespread pneumatisation) are especially clear. These new specimens confirm the avian nature of Gargantuavis and reveal new details about its pelvic anatomy, but provide little new evidence about its systematic position within Aves. The geographical distribution and general rarity of Gargantuavis are discussed.
      


  Article infos

Published in Vol.39-2 (2015)

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Abstract book of the 18th Conference of the European Association of Vertebrate Palaeontologists (EAVP), 5-9 July 2021, Benevento, Italy
Matteo Belvedere, Verónica Díez Díaz and Raffaele Sardella
Keywords: 2021; Benevento; EAVP

doi: 10.18563/pv.eavp2021
 
  Abstract

    Welcome to the 18th conference of the EAVP, the first online meeting of our association. The pandemic emergency made it impossible to organize the in-person meeting in Benevento as we all had hoped. However, we couldn’t miss another EAVP meeting. Therefore, this year we are meeting online, trying to make the experience the closest to the in-person meeting possible, in order to offer the delegates the opportunity to share knowledge, build new networks and reinforce the old ones. We have received 137 communications, with more than 150 delegates from 24 countries. All the abstracts have passed a peer review process and are part of this special volume of Palaeovertebrata, the official journal of the EAVP. This year we are also offering a variety of workshops, roundtables and symposia on different topics. These include the annual “Pride EAVP: An LGBTQ+ Roundtable” and “Women in Palaeontology Roundtable Discussion”, together with the workshops on “Gendered Perspective in Palaeontological Research: from Definition to Action”, “International Palaeontology Education: Virtual Teaching and Real-World Learning”, “Stepping out of Academia: Why, When and How?”, “Introduction to Hypothesis Testing in Statistics”, “The Early-Middle Pleistocene Transition: Marked Mammal Turnover and Ecosystem Dynamic” (included in the early event for the XXI INQUA Congress in Rome 2023, “A Mediterranean Perspective on Quaternary Sciences”). To conclude, we are hosting two symposia on “Palaeoart: Diversity on and behind the Canvas” and “3D fossils, Robotic and Experimental Palaeontology”. We wish you all a happy and productive meeting. And see you in Benevento next year! 


  Article infos

Published in Special Volume 1-2021 (2021)

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Palaecarcharodon orientalis (Sinzow) (Neoselachii : Cretoxyrhinidae), from the Paleocene of maryland, USA.
Gerard R. Case
Keywords: Maryland; Palaeocarcharodon; Paleocene; Selachian; Systematics; U.S.A.
 
  Abstract

    Recent collecting of fossil vertebrate remains from the lowermost member of the Aquia Formation (Paleocene), has enabled me to report here for the very fIrst time, the earliest occurrence for the teeth of Palaeocarcharodon in the fossil record of the New World.
    This report represents only one species of neoselachian from this locality, the remaining fauna of which will subsequently be described. 


  Article infos

Published in Vol. 19, Fasc. 1 (1989)

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

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


  Article infos

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

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Macroscelidea, Insectivora and Chiroptera from the Miocene of east Africa.
Percy M. Butler
Keywords: Chiroptera; East Africa; Insectivora; Macroscelidea; Miocene; Systematics
 
  Abstract

    The East African Miocene Macroscelidea, lnsectivora and Chiroptera are revised on the basis of new material. New taxa proposed are: Miorhynchocyon, .n. gen. (Macroscelididae): Míorhynchocyon meswae, n. sp.: Pronasílío ternanensis. n. gen.. n. sp. (Macroscelididae); Hiwegicyon juvenalis, n. gen. n. sp. (Macroscelididae); Parageogale, n. gen. (Tenrecidae): Prochrysochlorinae, n. subfam. (Chrysochloridae): Propottininae, n. subfam, (Pteropodidae); Chamtwaria pickfordi, n. gen., n. sp. (Vespertilionidae). Gymnurechnínus songhorensis is synonymised with G. camptolophus. The new material provides additional information on the dentition, especially of Myohyrax oswaldi. Galerix africanus. Amphechínus rusingensis, Protenrec tricuspis and Parageogale aletris. Partial skulls are described of Amphechinus rusingensis, Protenrec tricuspis, Prochrysochloris míocaenicus and Taphozous incognita. The oldest member of the Macroscelidinae (Pronasilio) is described from Fort Ternan. Galerix africanus is closely related to G. exilis from Europe. Amphechinus rusingenesis is compared with Asiatic Oligocene Erinaceinae. The Miocene age of Crocidura is rejected. On the evidence of humeri, the following families of Chiroptera are newly reported: Pteropodidae, Nycterididae, Vespertilionidae, Molossidae. Propotto is regarded as an offshoot from the Pteropodidae, not ancestral to modern forms. Chamtwaria is a primitive vespertilionoid, provisionally placed in the Kerivoulinae. Erinaceidae probably entered Africa at the beginning of the Miocene, before 20 Ma. Faunistic differences between deposits are largely to be ascribed to differences in local environment. 


  Article infos

Published in Vol. 14, Fasc. 3 (1984)

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Analysis of changing diversity patterns in Cenozoic land mammal age faunas, South America
Larry G. Marshall and Richard L. Cifelli
Keywords: Cenozoic; Chronofaunas; diversity; Equilibrium theory; Extinction; Land mammal faunas; Origination; South America
 
  Abstract

    Comparison of various measurements of taxonomic evolution using stratigraphic range data for orders, families and genera of land mammals indicates several means by which deficiencies of the South American fossil record (e.g., presence of hiatuses, unequal temporal and geographic representation of ages, unequal systematic treatment) may be normalized, thus permitting a less distorted appreciation of diversity pattern and trend. Initial radiation of native taxa resulted in a relative equilibrium by early Eocene time. Subsequent increases in absolute diversity were apparently induced by immigration at the family level and by environmental factors at the generic level. Miocene through Pleistocene phases of faunal stability, herein characterized as chronofaunas, are punctuated by rapid turnover events resulting from a complex of factors, including adaptive radiation of immigrant taxa into unoccupied eco-space; environmental and concomitant habitat change induced by orogenic events of the Andes; and biotic interactions between native and immigrant taxa, including competition and prey naivete. The first two factors account for major faunal transitions in the South American middle and late Tertiary; immigration-induced turnover may have been of greater importance in shaping the character of the fauna upon the Great American Interchange and the arrival of man in the Neotropics 


  Article infos

Published in Vol. 19, Fasc. 4 (1990)

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Les traces de pas d'amphibiens, de dinosaures et autres reptiles du Mesozoïque Français : inventaire et interprétations.
Georges Gand, Georges Demathieu and Christian Montenat
Keywords: Footprints; France; Inventory; Mesozoic; palaeontology; palaeovenvironments; Stratigraphy

doi: 10.18563/pv.35.1-4.1-149
 
  Abstract

    Since the 19th century, thousands of footprints were observed in the geological series of the French Mesozoic. All are located in the Triassic and Jurassic. After a promising beginning, in France, it is only a few papers which will be published in the first half 20th century, unlike the USA and of others countries of Western Europe. One ought to wait about 1950 for a revival and now they are nearly 200 papers which were devoted to the ichnofossils. The literature abundance and the renewed interest of the naturalists for the palichnologic studies decided to us to write a synthesis work. This one begins with a stratigraphic inventory in which, localisation, age and paleontological contents of about 180 fossiliferous sites are specified. After having pointed out the followed methods, the footprints paleontological interpretation is then approached in detail and the results obtained are replaced in stratigraphy to deduce the fauna evolution during the Mesozoic. So, it appears that Ichnologic data, more varied and rich in the Triassic and Liassic than those relating to the bones, very rare for the considered periods, are very informative. The middle Triassic (Anisian-Ladinian), thus reveals Cotylosauria, Lepidosauria, Crurotarsi with Rauisuchia, Ornithosuchidae, Crocodylia and Dinosauromorpha more the "Prodinosauria": Dinosamiforme whose skeletons are known in Argentina but only in Ladinian. The rather fast domination of Dinosaurs during Norian is also as well shown. The almost exclusive presence of their footprints, up to fifty cm long, in the Lower Hettangian indicates their supremacy in the environments. Footprints characterise not very deep life places located between inter-supratidal limits and often out of water. Sedimentologic and Palaeontologic studies showed that they were great coastal spaces during Middle Triassic, flood-plain with sebkhas while Upper Triassic, and a large !!coastal marsh!! in Grands-Causses during Liassic in which, mainly, fine stromatolithic layers were deposited. During the same periad, bay beaches spread in Vendée. During the Middle Jurassic, they are also brackish to lacustrine environments and recifallagoons in- the Upper Jurassic. Numerous measurements of the footprints and trackways directions showed that the animaIs moved there in weil defined directions, for long periods. They seem due to the palaeotopography of the life environments relatively stable. Also, the discovery of vegetal radicular networks and small footprints far away from the continental borderlands has suggested that the animals continuously lived in these palaeoenvironnements, belonging to large ecosystems, where the sedimentation rate was weak. This explains that thebadies could not fossilize there but only their footprints through the cyanobacterian action in main cases. From the vertical distribution of different ichnospecies, defined with adapted statistical methods, explained in this work, a palichnostratigraphy was established for the Middle Triassic. Although the footprints are also abundant in Hettango-Sinemurian of "Grands-Causses" and the Vendée, it was not possible, up to now, to establish any zonation in this series; Probably because the palichnofauna is too little diversified there, currently reduced to a majority of Theropods II-IV tridactyl traces.
      


  Article infos

Published in Vol. 35, Fasc. 1-4 (2007)

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Les traces de pas de Dinosaures et autres Archosaures du Lias inférieur des grands Causses, Sud de la France
Georges Demathieu, Georges Gand, Jacques Sciau, Pierre Freytet and Jacques Garric
Keywords: Dinosauroid footprints; France; Grands-Causses; Hettangian; ichnostratigraphy; paleoenvironments; Sinemurian; statistical results

doi: 10.18563/pv.31.1-4.1-143
 
  Abstract

    The Causses" is a near 3400 km2 large plateau located in the south of France. Here the first dinosaur footprints where found in 1935. After this, this area has yielded an ever-increasing number of ichnites now in excess of 500 specimens. These latter, 15 to 50 cm long, tridactyl or tetradactyl footprints of generally biped animals, were discovered at the surface of Hettangian to lower Sinemurian dolomite layers within 4 distinct stratigraphic units. The 35 sites bearing ichnites are located on the plateau margin. For the first time, morphologic characters studied through descriptive statistic methods with the usual parameters and classical Student and Snédecor tests, allowed us, to divide the whole set of biped traces into 6 ichnospecies. Their definitions are further constrained by multivariate statistical results using Principal Component Analysis (PCA), Factor Analysis of correspondances (FAC) and Discriminant Analysis (DA). All have confirmed the morphologic observations. So that now, the following taxa are identified : Grallator variabilis, G. lescurei, G. sauclierensis, G. minusculus, Eubrontes giganteus, Dilophosauripus williamsi, cf. Moraesichnium, Orníthopus fabrei nov ichnosp. The more immediately visible differences relate to the interdigital II-IV divarication and the digit length ratio. To this panel, we must add Batrachopus deweyi and shapes suggesting Trisauropodichnus and/or Anomoepus. Among all ichnite associations described in the lower Liasic, the New England assemblage presents the most affinities with ours. It shows the ichnotaxa Grallator, Dilophosauripus, Eubrontes, Batrachopus without forgetting Ornithopus fabrei nov. ichnosp. which is close to Ornithopus gallinaceus from the Massachusetts and Connecticut basins. On comparing the present early Jurassic ichnofauna of the Causses with the ones of the Middle and Upper Triassic formations of the eastem border of the Massif Central (France), it appears that tridactyl footprints become more and more numerous and large from Triassic to Early Jurassic. In the Causses, these latest are prevalent but in Quercy (France), Poland, Italy, USA, they are also associated with Omithopoda, Thyreophora and Sauropoda ichnites. Footprint areas considered here were generaly under an arid climate. Animals that passed by were heavy and bulky possible Megalosaur trackmakers, and lighter and slender Coelophysids or Ceratosaurs. For all, these areas were pathways as the orientations of the trackways seem point out. The directions followed by these reptiles were without any important variation during the Hettango-Sinemurian stages. These areas were also used from time to time by Crocodilomorpha and may be tetradactyl (I-IV) bipedal avian Theropods. However, the number of such trackways in sites, sometimes substantial, should not lead us to overestimate the trackmakers populations. These last were probably relatively moderately abondant in this inter-supratidal swamp environment. In the Causses, ichnites are connected with former algo-laminated deposits (Algal mats) which were rapidly hardened by means of calcitisation of cyanobacteria. The result has been a moderate depth of footprints; autopodia disturbing only a few cm of the carbonate substrate. Other fossils have been discovered : invertebrates with thin bivalve and gastropod shells, crustaceans tests and plants. These latter suggest the existence of paleomangroves like environments but also continental vegetation periodically overruning the swamp environment during regression/transgression cycles. At these times, wooded parts of it, could become protecting, feeding, resting and nesting places.

      


  Article infos

Published in Vol. 31, Fasc. 1-4 (2002)

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Archosauriform teeth from the upper Triassic of Saint Nicolas-de-Port (Northeastern France).
Pascal Godefroit and Gilles Cuny
Keywords: Archosauriforms; Graoullyodon hacheti; Saint-Nicolas-de-port; Teeth; Upper Triassic
 
  Abstract

    The Late Triassic locality of Saint-Nicolas-de-Port (Meurthe-et-Moselle, France) has yielded numerous isolated teeth belonging to archosauriform reptiles. The following tooth groups can be identified: heterodont phytosaurs, the pterosaur Eudimorphodon, the prosauropod dinosaur Plateosaurus, three types of putative ornithischian teeth and 13 types of carnivorous Archosauriformes indet. Apparent venom-conducting teeth belonging to a new taxon of ?Archosauriformes (Graoullyodon hacheti nov. gen. nov. sp.) are also described. From a palaeogeographical point of view, the ornithischian teeth from Saint-Nicolas-de-Port (if their attribution is confirmed) are the oldest fossils of this group in Europe. The biostratigraphic distribution of the tooth forms mostly suggests a Late Norian or Early Rhaetian (depending on current interpretations) age of the deposits, but do not provide more precisions than fossils previously described from the area. The dietary habits and, consequently, the palaeoecological relationships of the different vertebrate groups discovered at Saint-Nicolas-de-Port are tentatively established: the ornithischian and prosauropod teeth reflect a herbivorous diet, whereas the other archosauriform teeth are probably from camivores or omnivores.

      


  Article infos

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

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There were giants upon the earth in those days
Pierre-Olivier Antoine
Keywords: Eurasia; history of science; Indricotheriinae; Paleogene; Rhinocerotoidea

doi: 10.18563/pv.38.1.e4
 
  Abstract

    Rhinoceros Giants: the Paleobiology of Indricotheres. Donald R. Prothero. Life of the Past Collection, Indiana University Press; 160 pp. (66 b&w illustrations). Hardback (7x10”): USD 42.00 plus shipping. ISBN: 978-0-253-00819-0. E-book: USD 34.99. ISBN: 978-0-253-00826-8.
      


  Article infos

Published in Vol.38-1 (2014)

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Preliminary report on the fishes (Chondrichthyes & Teleostei) from the lower Oligocene (Rupelian) Red Bluff Clay at site AMo-9, Monroe County, Alabama, USA
Jun A. Ebersole, David J. Cicimurri, Lindsey M. Stallworth and Andrew D. Gentry
Keywords: Batomorphii; Elasmobranchii; Galeomorphi; Gulf Coastal Plain; Vicksburg Group

doi: 10.18563/pv.47.2.e2
 
  Abstract

    Herein we describe a small but relatively diverse assemblage of fossil fishes derived from the lower Oligocene (Rupelian) Red Bluff Clay at site AMo-9 in Monroe County, Alabama, USA. Identified amongst the remains are 15 unequivocal taxa representing 11 families within five orders, and one additional taxon represents an unknown order and family. Taxa identified include Eostegostoma sp., Otodus (Carcharocles) sp., Mitsukurinidae/Carchariidae indet., Macrorhizodus praecursor, Galeorhinus sp., Negaprion gilmorei, Physogaleus sp., “Sphyrna” sp., Galeocerdo sp., cf. “Aetobatus” sp., Sphyraena sp., Xiphiorhynchus kimblalocki, Xiphiorhynchus sp., Cylindracanthus ornatus, and C. rectus. Several additional fossils could not be identified beyond Lamniformes, Carcharhiniformes, and Teleostei, but they likely belong to one of the identified taxa within this paleofauna. All of the fishes previously reported from the Red Bluff Clay within the entirety of the Gulf Coastal Plain of the USA are otolith-based, and each of the 15 unequivocal taxa reported herein are important new records for this lithostratigraphic unit. In particular, the Eostegostoma sp. and Xiphiorhynchus spp. specimens represent the first occurrences of these taxa in Alabama. The specimens of C. ornatus, Eostegostoma sp., and X. kimblalocki are stratigraphic and temporal range extensions from the middle and late Eocene into the Rupelian Stage of the Oligocene. Other described taxa may represent transitional forms between those described from the late Eocene and late Oligocene within the region. This study provides a tantalizing preliminary view into faunal transitions that occurred amongst marine fishes across the Eocene/Oligocene boundary within the Gulf Coastal Plain of the USA. 


  Article infos

in press

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Dating dinosaur oodiversity: chronostratigraphic control of LateCretaceous oospecies succession.
Nieves Lopez-Martinez
Keywords: Biostratigraphy; Chronology; dinosaur eggshells; Late Cretaceous
 
  Abstract

    An increasing fossil record of dinosaur eggs and eggshells allows putting ootaxa within a chronostratigraphic framework, in order to study their distribution pattern leading eventually to their use as biochronological markers. For these purposes, high-quality data exists in four major regions; North America, South America, Europe and Asia (Central Asia and India). Most of the highly diverse dinosaur egg record has been dated as Latest Cretaceous in age (Campanian-Maastrichtian), reaching the Cretaceous-Tertiary boundary closer than the dinosaur bone record. However, dating continental sections is problematic and need to be carefully verified, as it appears when comparing the European dinosaur eggshell record from two well-studied areas. Ootaxa distribution in both sides of the Pyrenees (Tremp and Aix basins) shows comparable oospecies successions, but different chronology. This disagreement probably indicates that one or both successions have a wrong chronostratigraphic calibration.  


  Article infos

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

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Recherches de mammifères paléogènes dans les départements de l'Aisne et de la Marne pendant la deuxième moitié du vingtième siècle
Pierre Louis
Keywords: Biochronology; Eastern Paris Basin; Fossil localities; Mammals; paleoenvironments; Paleogene; Paleogeography
 
  Abstract

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


  Article infos

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

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Pronycticebus neglectus - an almost complete adapid primate specimen from the Geiseltal (GDR)
Urs Thalmann, Hartmut Haubold and Robert D. Martin
Keywords: Adapiformes; Eocene; Paleoecology; PHYLOGENY; Pronycticebus neglectus
 
  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. 


  Article infos

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

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Types dentaires adaptatifs chez les sélaciens actuels et post-paléozoïques.
Henri Cappetta
Keywords: Dental types; evolution; Fossil selachians; Recent selachians; Trophic adaptations
 
  Abstract

    The dentition of selachians is characterized by an often very pronounced heterodonty involving a great morphological diversity. Despite this fact, the dentitions of selachians can be grouped in a rather reduced number of dental types corresponding to trophic adaptations: grasping, tearing, cutting, crushing, grinding and grasping-grinding type. The numerous exemples of convergence and parallelism that can be observed in fossil selachians and between Recent and fossil ones is the result of this reduced number of dental types. These dental specialisations allow to try a reconstruction of the way of life of fossil forms. 


  Article infos

Published in Vol. 16, Fasc. 2 (1986)

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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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La morphologie dentaire des Thalattosuchia (Crocodylia, Mesosuchia).
Patrick Vignaud
Keywords: Dental morphology; Dental types; feeding habits.; Jurassic; Metriorhynchidae; Systematics; Teleosauridae; Thalattosuchia
 
  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.

      


  Article infos

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

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Neolicaphrium recens Frenguelli,1921,the only surviving proterotheriidae (Litopterna, Mammalia) into the south american Pleistocene.
Mariano Bond, Daniel Perea, Martin Ubilla and Adan Tauber
Keywords: Litopterna; Neolicaphrium recens; Pleistocene; Proterotheriidae; South America
 
  Abstract

    The litoptem Proterotheriidae are extinct endemic South American ungulates frequently used as an example of evolutionary convergence with the horses. They were considered to be exclusively Tertiary representatives with the youngest record being in the late Pliocene, before the appearence of the equids and cervids during the Great American Interchange. Two undoubted Pleistocene records in Argentina and the specimen here described from Uruguay, confirm the persistence of the proterotherids into that period. In the Quaternary, these ungulates are found outside the typical pampean region and probably were confined to a few northern and warmer more forested relictual microhabitats.

      


  Article infos

Published in Vol. 30, Fasc. 1-2 (2001)

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