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Page 16 of 18, showing 20 record(s) out of 359 total

Long-term fidelity of megaoolithid dinosaurs to a large breeding-ground in the Upper Cretaceous of Aix-en-Provence (southern France).
Géraldine Garcia, Yves Dutour, Isabellle Cojan, Xavier Valentin and Gilles Cheylan
Published online: 12/15/03

Keywords: Large nesting ground; megaloolithid eggs; Southern France; Upper Cretaceous

  Abstract

    We present here the preliminary results from a new nesting site "Sextius-Mirabeau", discovered close to the historical centre of Aix-en-Provence in Upper Cretaceous deposits. This extensive megaloolithid nesting ground, the first large scale excavation (3225 m²) in France, yielded more than 530 eggs, some organized in clusters. Their study reveals the reproductive strategy of the megaloolithid egglayer group which indicates nesting fidelity and gregarious behaviour.  


  PV article infos

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

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Révision des Artiodactyles de l'Eocène moyen de Lissieu (Rhône)
Jean Sudre
Published online: 5/15/72

Keywords: Artiodactyles; Dichodon; France

  Abstract

    The object of this work is the study of the artiodactyls of the karstic locality of Lissieu near Lyon. Among the sixteen species counted, five (Hyperdichobune nobilis, Hyperdichobune sp., Haplabunodon mulleri, Tapirulus depereti and Pseudamphimeryx schlosseri) are cited for the first time in this fauna. The description of part of the anterior dentition of «Dichobune» langi permits the referal of this species to the genus Hyperdichobune. The new selenodont species Dichodon lugdunensis  described in this work belongs, with its ancestor Dichodon simplex, to a lineage distinct from that of Dichodan cartieri and Dichodon ruetimeyeri. Finally, the taxonomic reality of the Lissieu species, Lophiobunodon rhodanicum Deperet, is justified. All the other species have been compared with those of Egerkingen. Even though with most of them no difference in age can be shown between the two deposits, some however indicate clearly by their degree of evolution that Lissieu is slightly more recent than Egerkingen. ln the history of Eocene mammals, the Lissieu fauna, because of its homogeneity, can be considered as a sure reference fauna of the Auversian period. 


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Published in Vol. 05, Fasc. 4 (1972)

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Présence de Palaeobatrachidae (Anura) dans des gisements tertiaires Français caractérisation, distribution et affinités de la famille
Colette Vergnaud-Grazzini and Robert Hoffstetter
Published online: 5/15/72

Keywords: Anura; Palaeogeography; Systematics

  Abstract

    The Palaeobatrachidae until now have not been reported from France. The present note makes known the discovery of very significant remains in three Tertiary localities of France: Cernay (late Paleocene), Laugnac (late Aquitanian) and Sansan (middle Helvetian). The osteologic characters, as well as the geographic and stratigraphic distribution of the family are re-stated with added details. The Palaeobatrachidae are a European family known from the late Jurassic of Catalonia (publication in course by J. Seiffert) to the Plio-Pleistocene (pre-Mindel) of Poland and Rumania. By their way of life and certain osteologic characters they are similar to the Pipidae, but they are distinguished by profound differences. It would be rash to include them in the Pipoidea or even in the Aglossa. They are apparently an independant group, essentially holarctic, which held in Europe a role equivalent to that played by the Pipidae south of Tethys. 


  PV article infos

Published in Vol. 05, Fasc. 4 (1972)

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Les rongeurs de l'Oligocène inférieur d'Escamps
Monique Vianey-Liaud
Published online: 12/1/74

Keywords: Escamps; Quercy Phosphorites; Rodents; Theridomyidae

  Abstract

    La faune de Rongeurs d'Escamps (Lot) bien que relativement pauvre en espèces (dix) s'avère riche d'enseignement pour les Rongeurs de l'Oligocène inférieur d'Europe Occidentale. Cette periode semble caracterisée par une cladogenèse des Théridomyines. A Escamps, un nouveau genre (Patriotheridomys) est décrit ainsi qu'une nouvelle espèce de Theridomys. Avec Oltmamys platyceps, décrit ici plus complètement et désormais bien situé stratigraphiquement, les deux espèces précédentes constituent un ensemble original du Sud de la France. A la même époque, en Angleterre, Allemagne et Espagne, des espèces «régionales» de Théridomyinés se dersifient.  A côté de ces formes qui ne semblent pas franchir la «Grande Coupure» sont représentées deux lignées d'Issiodoromyinés (Elfomys sp et Pseudoltmomys cuvieri), une de Théridomyiné (T. (Blainvillimys) rotundidens) ainsi qu'un Gliridé, Gliravus priscus (que l'on différencie nettement de la deuxième lignée des Gliravus oligocènes : G.  meridionalis -> G. majori). On retrouve ces formes dans les gisements plus récents du niveau de Hoogbutsel où elles sont à peine plus évoluées. Le fait que les degrés évolutifs de ces lignées soient très proches laisse supposer que le laps de temps séparant les niveaux d'Ecamps et Hoogbutsel fut relativement court. 


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

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Les insectivores des phosphorites du Quercy
Jean-Yves Crochet
Published online: 11/15/74

Keywords: Insectivores; Quercy Phosphorites

  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. 


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

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Les Entélodontes des phosphorites du quercy
Michel Brunet
Published online: 11/15/74

Keywords: Entelodontes; Quercy Phosphorites

  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.

      


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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
Published online: 11/15/74

Keywords: Carnivores; Quercy Phosphorites

  Abstract

    Abstract not available 


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

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Sur le remplissage des "poches à phosphorite" d'Aubrelong (commune de Bach, Lot)
Bernard Gèze
Published online: 11/15/74

Keywords: Aubrelong; Quercy Phosphorites

  Abstract

    Abstract not available 


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

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Analyse d'ouvrage: “J.J. THOMASON (Ed.): Functional morphology invertebrate paleontology (1995)”
Jacques Michaux
Published online: 3/18/96

Keywords: Book review; Functional morphology

  Abstract

    Functional morphology invertebrate paleontology, édité par Jeffrey J. THOMASON, 1995. Cambridge University Press, xi + 277 p. ISBN 0-521-44095-5, f. 45,00 ($ 69,95).

    La morphologie fonctionnelle appliquée aux fossiles demeure un sujet à la fois passionnant et important. Passionnant, car elle s'adresse à des êtres disparus, aux combinaisons de caractères parfois inattendues et sans contrepartie chez les formes actuelles. Sujet important, car il faut, au delà de la constatation classique de l'adéquation de la forme des organes à leur fonction, expliquer l'origine des structures par évolution. L'évolution ou descendance avec modification, implique que les êtres vivants sont reliés les uns aux autres et qu'i! est possible de tenter à l'aide d'un raisonnement par inférence, la caractérisation des ancêtres en fonction des traits des formes auxquelles ils ont donné naissance. Mais il faut ajouter que par sa fonction, la structure relie immédiatement l'animal à son milieu puisqu'elle assure un rôle biologique. 


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Published in Vol. 25, Fasc. 1 (1996)

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Analyse d'ouvrage: “A.G. SMITH, D.G. SMITH & B.M. FUNNELL: Atlas of Mesozoic and Cenozoic coastlines (1995)”
Jacques Michaux
Published online: 3/18/96

Keywords: Atlas; Book review; Cenozoic; Coastlines; Mesozoic

  Abstract

    ATLAS OF MESOZOIC AND CENOZOIC COASTLINES, par Alan G. SMITH, David G. SMITH & Brian M. FUNNELL, 1995. Cambridge University Press, 99 p., 31 cartes, 3 tab!., 2 fig. ISBN 0-521-45155-8.

    L' "Atlas of Mesozoic and Cenozoic coastlines" succède avec bonheur aux "Mesozoic and Cenozoic paleocontinental maps" de Smith & Briden, publié en 1977. 


  PV article infos

Published in Vol. 25, Fasc. 1 (1996)

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Analyse d'ouvrage: “M. ARSENAULT, H. LELIÈVRE & P. JANVIER (Eds.): Etudes sur les vertébrés inférieurs — VII e Symposium International, Parc de Miguasha, Québec, 9- 22 Juin 1991 (1994)”
Alain Blieck
Published online: 3/18/96

Keywords: Book review

  Abstract

    Etude sur les vertébrés inférieurs (VIIe Symposium International, Parc de Miguasha, Québec, 9-22 Juin 1991), édité par Marius ARSENAULT, Hervé LELlÈVRE & Philippe JANVIER, 1994. Bulletin du Muséum National d'Histoire Naturelle, Paris, 4e Série, T. 17, Section C, n° 1-4, 529 p.

    Ce volume spécial du Bulletin du Muséum réunit les actes du congrès international sur les Vertébrés inférieurs qui s'est tenu au Québec en 1991. 


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Published in Vol. 25, Fasc. 1 (1996)

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Diversity of triconodont mammals from the early Cretaceous of North Africa-affinities of the Amphilestids
Denise Sigogneau-Russell
Published online: 10/15/03

Keywords: amphilestines; Early Cretaceous; gobiconodontines; North Africa; Teeth; triconodonts

  Abstract

    The mammalian fauna (represented only by isolated teeth) from the early Cretaceous of Morocco includes a number of non-'therian' specimens, characterized by the antero-posterior alignement of the main molar cusps. This assemblage is very heterogenous, including forms (among them Gobiconodon palaios sp. nov.) that can be related to Laurasian triconodonts and several forms so far known only in this part of Gondwana (among them Kryptotherium polysphenos gen. et sp. nov.). The latter, in particular, exemplifies the diversity of the mammalian dental morphology in the Mesozoic, often largely underestimated. In the last part of this paper, the 'therian' affinity of the 'amphilestids' is discussed, on the basis of the arrangement of molar cusps, the interlocking mechanism and the occlusal pattem. 


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Published in Vol. 32, Fasc. 1 (2003)

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Koobi Fora Research Project, volume 3. The fossil ungulates: geology, fossil artiodactyls, and palaeoenvironments, édité par John Michael HARRIS, 1991. Clarendon Press, Oxford, xvi + 384 p. ISBN 0-19-857399-5.
Jean Sudre
Published online: 2/11/93

Keywords: Artiodactyls; palaeovenvironments; Ungulates

  Abstract

    Avec ce volume se clôture l'étude géologique et paléontologique des sites à hominidés de Koobi Fora. Il fait suite aux deux précédents ouvrages, parus respectivement en 1978 et 1983, consacrés également à l'étude des faunes recueillies sur ces gisements dans le cadre du Koobi Fora Research Project. 


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Published in Vol. 22, Fasc. 2-3 (1993)

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Cervus elaphus rossii (Mammalia, Artiodactyla), a new endemic sub-species from the Middle Pleistocene of Corsica
Elisabeth Pereira
Published online: 12/28/01

Keywords: Cervus elaphus; Corsica; Endemism; Pleistocene

  Abstract

    Several endemic deer remains from the Middle Pleistocene deposits of the Castiglione cave (Oletta, Haute-Corse) are examined here. A morphometric analysis allows to relate them to a new insular subspecies Cervus elaphus rossii. The bones were compared with those of the mainland early Middle Pleistocene subspecies Cervus elaphus acoronatus Beninde and the European species Cervus elaphus Linné (Late Middle Pleistocene and Upper Pleistocene forms (continental and insular)). The Castiglione fossil shows peculiar morphofunctional features in its appendicular skeleton suggesting a morphological convergence with certain Bovidae. 


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

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The endocranial cast and encephalization quotient of Ptilodus (Multituberculata, Mammalia)
David W. Krause and Zofia Kielan-Jaworowska
Published online: 2/11/93

Keywords: encephaIization quotient; endocranial cast; Montana; Multituberculata; olfactory bulbs; Paleocene; Ptilodus

  Abstract

    Simpson (1937a) reconstructed the brain of the Paleocene multituberculate Ptilodus as having the olfactory bulbs widest anteriorly, an unusual condition among mammals. Slight preparation and reexamination of the endocast specimens of Ptilodus reveals that the olfactory bulbs in fact taper anteriorly, as in the recently-described endocranial casts of three multituberculate species from the Late Cretaceous of Asia, and as in those of other mammals. The brain of Ptilodus was therefore essentially of the same general pattem as in other multituberculates. Ptilodus differs, however, in having the vermis more deeply inserted between the cerebral hemispheres. Other details concerning the endocast morphology of Ptilodus are clarified.

    The encephalization quotient (EQ) of Ptilodus is recalculated from revised estimates of both endocranial volume and body mass to fall somewhere within a broad range of values; from 0.41 to 0.62 if the olfactory bulbs are included and from 0.37 to 0.55 if they are not. In any case, the relative brain size of Ptilodus is roughly equivalent to that of Chulsanbaatar, the only other multituberculate for which EQ has been calculated, but considerably smaller than that of an average extant mammnal. 


  PV article infos

Published in Vol. 22, Fasc. 2-3 (1993)

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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: 12/28/01

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

  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.

      


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

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First report of an Eocene reptile fauna from Florida, USA
Alan J. Holman
Published online: 7/30/01

Keywords: Eocene; Fauna; Florida; Reptile; USA

  Abstract

    Fossils of the Trionychidae, Bataguridae or Emydidae, Palaeophis and Crocodylia from Chattahoochee, NW Florida, USA, represent the first report of an Eocene reptile fauna from Florida. 


  PV article infos

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

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Rythme et modalités de l'évolution chez les rongeurs à la fin de l'Oligocène-leurs relations avec les changements de l'environnement.
Bernard Comte
Published online: 12/15/00

Keywords: Environment; evolution; Oligocene; Rodents; Systematics

  Abstract

    The analysis of oxygene isotope variations as well as paleobotanical data suggest that the Oligocene/Miocene boundary corresponds to a transitional period marked by floristical and climatic variations. During this period, the pyreneo-alpine tectonics has contribued to modify the geography and western Europe landscapes. Faunal changes (appearances, extinctions, migrations) are observed in different mammalian groups, notably in the rodents. A study of the evolutionary trends and patterns in paleogene rodents is involved for the period ranging from level MP 28 of the Late Oligocene to the Early Miocene, including the Oligo-Miocene boundary.
    The Rodents fauna from the sites of Venelles (Bouches-du-Rhône District, France) and Thezels (Lot, France), previously mentionned in litterature, have been studied. The first description of the Eomyidae of La Milloque (MP 29) has been completed. These faunas are compared to those from various localities dating from the considered period. In La Milloque, a new representative of the Eomys species is described next to a form close to Rhodanomys hugueneyae ENGESSER, 1987. It is the Eomys milloquensis nov. sp., the likely descendant of Eomys quercyi COMTE & VIANEY-LIAUD, 1987. Two new species are also described in Thezels: Eucricetodon thezelensis nov. sp., resulting from a likely and local evolution of Eucricetodon praecursor (SCHAUB, 1925) from La Milloque, which, in the same geographic area, could be at the origin of Eucricetodon hesperius ENGESSER, 1985 from Paulhiac. Plesiosminthus admyarion nov. sp., quite distinct from Plesiosminthus schaubi VIRET, 1926, which announces Plesiosminthus myarion SCHAUB 1930. Venelles 'Plesiosminthus schaubi population is considered as a sub-species, named Plesiosminthus schaubi meridionalis nov. subsp. New phylogenetic patterns are proposed. Among the Eomyidae, a quantification of various features of the M1-2/ crown (hypsodonty, degree of abrasion, occlusal angle, state of development of the I and V anticlines), and a comparison with the occlusal diagram of the other teeth among various other populations allows a more efficient separation of Eomys and Rhodanomys genera. In Western Europe, and within this period, it finally does not seem possible to gradually connect the genus Eomys to the genus Rhodanomys. The evolution of the Eomys quercyi - milloquensis lineage seems to underline a similar evolution to that which may have led from the Eomys to the Rhodanomys form. The latter which appears totally accomplished at level MP 29 of the Oligocene is considered as an immigrant. If we compare the most representative species of the Venelles, Thezels, and Coderet sites, (i.e. Rhodanomys, Eucricetodon, Adelomyarion, Peridyromys, Plesíosminthus), it becomes impossible to confirm their biochronological separation. The noticeable differences between the populations may be interpreted as geographical variations. An explanation to these variations, and to fauna's evolution during the Late Oligocene and Early Miocene can be found in the environmental modifications, supported by isotopic, paleobotanical and sedimentologic analysis. A tentative reconstruction of the environments is attempted by the cenogram method. The analysis of the fluctuations of fauna's diversity shows variations which may be correlated to a drop in temperature at MP 29, during the Late Oligocene, followed by an increase in temperature along with an aridity phenomenom, during the basal Miocene (MN O).The confrontation of various methods give the opportunity of reconstituting and comparing the evolution of the environment of three sequences of sites chosen from different regions. Ecological affinities of various rodents' species are being examined. It is possible to consider that the integration of all the conclusions resulting from this study should lead to an explanation to the evolution of rodents for the period around the Oligocene-Miocene boundary. The site of Coderet- level 3- would be posterior to the latter, at the beginnig of the Miocene, and would mark the level MN 0 of the Aquitanian.

      


  PV article infos

Published in Vol. 29, Fasc. 2-4 (2000)

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Mammals and stratigraphy of the continental mammal-bearing Quarternary of South America
Larry G. Marshall, Annalisa Berta, Robert Hoffstetter, Rosendo Pascual, Osvaldo A. Reig, Miguel Bombin and Alvaro Mones
Published online: 12/16/84

Keywords: Geochronology; Mammalia; Quaternary; South America; Stratigraphy

  Abstract

    Previous chronological arrangements of South American Quaternary land mammal faunas are appraised on the basis of current geological and paleontological data. Three South American late Pliocene-Pleistocene land mammal ages are conventionally recognized, from oldest to youngest, the Uquian, Ensenadan, and Lujanian ; all are defined on Argentine faunas.

         The Uquian is based fundamentally and historically on the fauna from the Uquía Formation in Jujuy Province, northwestern Argentina. Important known formations in Argentina yielding Uquian Age faunas include the sub-surface Puelche Formation (or Puelchense) near the city of Buenos Aires, and the Barranca de Los Lobos and Vorohué Formations between Mar del Plata and Miramar, Buenos Aires Province. A tentative subdivision is propos-ed for the Uquian into three subages based on knowledge of the Mar del Plata-Miramar sequence, from oldest to youngest, the Barrancalobian, Vorohuean, and Sanandresian. In Argentina the Uquian is presently marked by the first known record of Scelidodon, Hydrochoeropsis, Ctenomys, Canidae, Ursidae, Gomphotheriidae, Equidae, Tapiridae, Camelidae, Cervidae, and the last known record of Thylatheridium, Thylophorops, Dankomys, Eumysops, Pithanotomys, Eucoelophorus, Hegetotheriidae, Sparassocynidae, and Microtragulidae.

    The Ensenadan Age is based on the fauna from the Ensenada Formation near the city of Ensenada, Buenos Aires Province. In Argentina the Ensenadan is marked by the first known record of Lomaphorus, Neothoracophorus, Plaxhaplous, Cavia, Lyncodon, Lutra, Galera, Smilodon, Dicotyles, Lama, Vicugna, the last known record of Orthomyctera, and the only known record of Brachynasua.

         Typícal beds of late Lujanian Age in Argentina consist of fluvial deposits occupying stream channels, and shallow basins, often incised into beds of early Lujanian (i.e. Bonaerian of early workers) and Ensenadan Age. The Lujanian Age is based on a fauna from beds along the Rio Luján, about 65 km west of the city of Buenos Aires, Buenos Aires Province. The Lujanian in Argentina is marked by the first record of Equus, Chlamyphorus, and Holochilus, and the last record of Megatherioidea, Glyptodontoidea, Arctodus (=Arctotherium), Smilodon, Litopterna, Notoungulata, Proboscidea, Equidae, Morenelaphus, and Palaeolama.

       These land mammal ages are often difficult to recognize in other South American countries. The compositions of South American Pleistocene faunas vary with the environment. Some taxa were widely distributed in fossil deposits throughout the continent, but their occurrences need not reflect synchroneity. This is a result of changing climates and habitats in time. Consequently, proposed intracontinental correlations need confirmation based on magnetostratigraphy and a radioisotope time scale. Paleontologic characterizations of these land mammal ages (i.e. first and last record, and guide fossils) are useful for much of Argentina, but extensions to most of the other parts of South America are at best tenuous.

    The majority of known non-Argentine Pleistocene faunas are believed to be Lujanian in age. Possible non Argentine early Pleistocene (Uquian) faunas include Ayo Ayo and Anzaldo in Bolivia, and Cocha Verde in southern Columbia. A possible middle Pleistocene (Ensenadan or early Lujanian) fauna is the Chichense of Ecuador. Paleomagnetic and radioisotopic date (MacFadden et al., 1983) clearly indicate that the greater part of the Tarija fauna (Bolivia) is Ensenadan in age.

      The end of the Pleistocene and beginning of the Holocene in South America is marked by extinction of nearly all large mammalian herbivores and their specialized large predators. Radiocarbon age determinations suggest that large scale extinctions of megafauna occurred between 15,000 and 8,000 yrs. B.P. (years before present). 


  PV article infos

Published in Vol. 14, Ext (1984)

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Mammals and stratigraphy : Geochronology of the continental mammal-bearing Tertiary of south America.
Larry G. Marshall, Robert Hoffstetter and Rosendo Pascual
Published online: 12/15/83

Keywords: Cenozoic; Geochronology; Mammalia; South America; Stratigraphy; Tertiary

  Abstract

    The principles and practices employed in establishment and recognition of South American land mammal ages are reviewed along with previous and present concepts of distinguishing time, rock, and faunal units. Previous chronological arrangements of South American Tertiary land mammal faunas are appraised on the basis of recent geological and paleontological data. Twelve South American Tertiary land mammal ages are here recognized [from oldest to youngest, Riochican (middle to late Paleocene); Casamayoran (early Eocene); Mustersan (middle Eocene); Divisaderan (late Eocene); Deseadan (early [to middle?] Oligocene); Colhuehuapian (late Oligocene); Santacrucian (early Miocene); Friasan (middle Miocene); Chasicoan (late Miocene); Huayquerian (latest Miocene); Montehermosan (early to middle Pliocene); and Chapadmalalan (late Pliocene)]. As all except the Friasian were originally defined on the basis of Argentine faunas, these are discussed first and at length, and each is reviewed with discussion of type locality, stratigraphy, type fauna, and faunal correlations. Non-Argentine faunas are then discussed country by country in alphabetical order.

         A review is given of radioisotope dates obtained on volcanic rocks (i.e., basalts, tuffs) associated with mammalbearing beds in Argentina. Based on these age determinations and on correlation of the late Tertiary land mammals involved in the interchange between North and South America, a chronology of South American land mammal ages correlated with North American land mammal ages and European marine stages is proposed.

    It is concluded that South America was an island continent through most of the Tertiary Period (ca 65 to about 3 Ma). As a result, the land mammal fauna of South America developed in isolation and was dominated by autochthonous endemic groups. Toward the end of the Tertiary (i.e., middle Miocene) a unique faunal balance had been achieved by the descendants of the ancient inhabitants (notoungulates, litopterns, condylarths, astrapotheres, edentates, marsupials) and of later (late Eocene) waif immigrants (caviomorph rodents, platyrrhine primates). A prominent feature of this mammal fauna was the combination of carnivorous and omnivorous marsupials with native placental herbivorous ungulates, subungulates, and edentates.

    Sometime during the late Miocene, a limited but important interchange of mammalian taxa between North and South America took place. Procyonids (raccoons and their allies), a group of North American origin, first appear in South America in strata of Huayquerian Age, while members of the extinct South American ground sloth families Megalonychidae and Mylodontidae first appear in North America in early Hemphillian time. These groups dispersed along island arcs before the appearance of the Panamanian land bridge in the Pliocene (ca 3.0 Ma). Cricetine rodents, a group of North American origin, are first known in South America in strata of Montehermosan Age. The known taxa are too advanced and diversified to be considered the first of this group to invade South America. lt is believed by some workers that these rodents arrived before the Montehermosan, possibly in the late Miocene or earlier, by waif dispersal from North America.

    The isolation of South America ended with the appearance of the Panamanian land bridge, which provided a direct, dry land connection between the two Americas. Across this portal an extensive interchange of terrestrial faunas occurred, and the fossil record documents an intermingling of these long-separated land mammals faunas.

          The beginning of this interchange by land route in South America is marked by the appearance of mammals which evolved from North American emigrants in the Chapadmalal Formation of Argentina. These include a mustelid (Conepatus), a tayassuid (Argyrohyus), and four genera (Akodon, Dankomys, Graomys, Reithrodon) of cricetine rodents. The appearance of this contingent of northern animals favors the existence of the Panamanian land bridge by this time. Likewise, a large number of terrestrial vertebrates of South American origin appear in North America in beds of late Blancan Age date around 2.7 Ma. Among the mammals are Neochoerus, Erethizon, Glyptotherium, Glossotherium, Kraglievichia, and Dasypus


  PV article infos

Published in Vol. 13, Ext (1983)

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