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Evolution de la lignée Megacricetodon collongensis-Megacricetotodon roussillonensis (Cricetidae, Rodentia, mammalia) au cours du Midocène inférieur et moyen dans le Sud de la France.
Jean-Pierre Aguilar
Keywords: Cricetids rodents; Evolutionary lineage; Lower and Middle Miocene; Mammalian biochronology; Megacricetodon new species; Southern France
 
  Abstract

    New populations of the genus Megacricetodon have recently been discovered in Southern France.Two new species are defined: M. lemartineli n. sp. and M. fournasi n. sp., their stages of evolution are intermediate between those of M. gersii and M. roussillonensis. Morphological and biometrical analysis indicate the presence of only one lineage: M. collongensis--M. collongensis-gersii--M. gersii--M.lemartineli nov. sp.--M. fournasi nov. sp. and M. roussillonensis. This observation allows to refine the chronology based on rodents, for the Late Early Miocene and the Middle Miocene in the Southern France.
    Comparisons with some iberian species are done. The validity of the French species M. bezianensis and M. bourgeoisi is discussed. 


  Article infos

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

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Book review : "Encyclopedia of Paleoherpetology"
Jean-Yves Crochet
Keywords: Book review; Paleoherpetology
 
  Abstract

    Encyclopedia of Paleoherpetology. In 19 parts ; Initiated by Prof. Dr. Oskar KUHN ; Edited by Dr. Peter WELLNHOFER, München. - Part. 17 A : Pelycosauria, by Dr. Robert R. REISZ, Erindael Campus, University of Toronto. 1986. VIII, 102 pp., 43 fig., 20,5 x 25,5 cm, soft cover : DM 140, - (Pref. - Price for subscribers to the whole series : DM 126, -). ISBN 3-437-30486-0. 


  Article infos

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

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Pairomys et Ectropomys : la fin d'une ambiguïté ; mise au point sur les Oltinomyinae et Remyinae (Rodenia, Theridomyidae).
Monique Vianey-Liaud, Norbert Schmidt-Kittler and Pablo Pelaez-Campomanes
Keywords: PHYLOGENY; taxonomy; Theridomyidae; Upper Eocene
 
  Abstract

    The description of new material of the Upper Eoœne of France, Southem Germany and Spain together with the restudy of the material described by Thaler (1966b) as Pairomys allows to confirm the validity of the genus Ectropomys up to know controversally discussed. As a consequence the subfamily Remyinae and Oltinomyinae can be defined precisely. The study of the dental characters shows that the Remyinae in fact belong to the Theridomyidae and represent a derived evolutionary unit within this family. The Oltinomyinae together with the Theridomyinae and Issiodoromyinae very probably form a monophyletic unit. 


  Article infos

Published in Vol. 23, Fasc. 1-4 (1994)

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Nouveau Dichobunidae (Artiodactyla, Mammalia) du gisement d'Aumelas (Hérault) d'âge Lutétien terminal
Jean Sudre
Keywords: Aumelas; Dichobunidae; Hérault; Middle Eocene; Upper Lutetian
 
  Abstract

    The faunal list of the mammals collected at the locality of Aumelas (Hérault, France) is revised. For the first
    time this Middle Eocene locality is precisely settled in the european chronological scale of "niveaux repères", between the levels of Bouxwiller and Egerkingen, in Uppermost Lutetian.
    A new Dichobunid from the site is described : Aumelasia gabineaudi n. g., n. sp. This new genus has primitive characters. and it may be in the descent of the Lower Eocene Protodichobune


  Article infos

Published in Vol. 9, Ext (1980)

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 La poche à phosphate de Ste-Néboule (Lot) et sa faune de vertébres du Ludien Supérieur. Introduction
Bernard Gèze, Jean-Claude Rage, Colette Vergnaud-Grazzini, France de Broin, Eric Buffetaut, Cécile Mourer-Chauviré, Jean-Yves Crochet, Bernard Sigé, Jean Sudre, Jean-Albert Remy, Brigitte Lange-Badré, Louis de Bonis, Jean-Louis Hartenberger and Monique Vianey-Liaud
Keywords: Eocene; Quercy Phosphorites
 
  Abstract

    Le Quercy est aujourd 'hui un vaste plateau calcaire, parcouru par un réseau karstique actif, profondément
    entaillé par des vallées aux falaises abruptes, comme celles du Lot ou du Célé. Sur un sol peu épais domine la forêt de chênes, accompagnés de cornouillers, érables, genévriers. La faune est pauvre, peu diverse, et les nombreux chasseurs se satisfont de gibier d'élevage ...

    Il y a trente cinq millions d'années environ, le paysage était bien différent. La période de l'Eocène supérieur, qui s'achevait, avait été chaude et humide, si l'on se réfère à la fois aux paléotempératures (calculées à partir de sédiments marins extra·européens) et aux restes fossilisés de végétaux typiquement tropicaux. 


  View editorial

Published in Vol. 08, Fasc. 2-4 (1978)

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Die Ohr-Region der Paulchoffatiidae (Multituberculata, Ober-Jura).
Gerhard Hahn
Keywords: Multituberculata; Ober-Jura; Paulchoffatiidae; Petrosum; Portugal
 
  Abstract

    The petrosal of the Paulchoffatiidae HAHN, 1969 is described and compared with that of younger multituberculates and of other Mesozoic mammals. The "Morrison petrosal", described by Prothero (1983), is also discussed; it probably belongs to the multituberculates. The reconstruction of the ventral side of the Paulchoffatiinae-skull, given by Hahn in 1987, is completed by addition of the otic and the occipital region. 


  Article infos

Published in Vol. 18, Fasc. 3 (1988)

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Le genre Leptolophus (Perissodactyla, Mammalia): morphologie et histologie dentaires, anatomie cranienne, implications fonctionnelles.
Jean-Albert Remy
Keywords: dental histology; Eocene; functional anatomy; Palaeotheriidae; skull anatomy; Southern France; Systematics
 
  Abstract

    A strong lophodonty, an extreme heterodonty, some hypsodonty and regular overlayings of coronal cement are prominent features of the genus Leptolophus (Palaeotheriinae = Palaeotheriidae s.s.). The histological pattern of the teeth unusually joins type II enamel prisms, characteristic of advanced ungulates, together with archaic features, such as an almost complete lack of Hunter-Schreger zonation and a weak expanse of peritubular dentine. The skull is narrow and slender, with an elongated ante-orbital facial region, a moderately notched nasal aperture, a rather elongated post-canine diastem, parallel zygornatic arches and a fairly dorsally located squamoso-mandibular joint.The functional analysis brings to light "ectolophodont" masticatory cycles with two phases, in which maximum power was applied, contrary to equíds, on hindmost teeth; likewise, skull accomodations to increasing height of the teeth are quite different. This study leads to the assumption that Leptolophus may have been light mammals, living in rather open surroundings, browsing on herbaceous plants or leaves cropped close to the ground. Moreover, it appears that it could have been some inadequacy of dental structures to the dietary, which leaded to quick wear of the teeth and to many enamel notches, but had been somewhat balanced by the early increase of hypsodonty, not induced in such a case by a biotop deterioration (as it will happen at the end of the Eocene). This ínadaptation might account for the short duration of the genus Leptolophus, whose the 3 species, L. stehlini, L. nouletí and L. magnus n. sp. are indeed confined in the level MP 16. Its geographical spreading (as far as known, South of western Europe) and the morphological pattern of its dentition suggest that this genus would have been related to early upper Eocene endemic spanish forms.





      


  Article infos

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

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The skull of Tetraceratops insignis (Synapsida, Sphenacodontia)
Frederik Spindler
Keywords: cranium; pelycosaur; Permian; therapsid origins

doi: 10.18563/pv.43.1.e1
 
  Abstract

    Tetraceratops insignis is known from a single, crushed skull from the Lower Permian of Texas. Its unique proportions and osteological details gained central meaning in the question of the origins of Therapsida since this early synapsid has been determined as the oldest and less derived therapsid. Apart from Tetraceratops, the ‘mammal-like’ Therapsida and their sister, the pelycosaur-grade Sphenacodontidae, are separated by one of the longest ghost lineages in tetrapod fossil record. However, the minor, though well justified critique faced insistent publication regarding the therapsid hypothesis. A carefull re-evaluation of the holotypic skull reveals that therapsid traits cannot be supported, including a rejection of the formerly supposed adductor shelf in the temporal fenestra. Increased understanding of ‘pelycosaur’ character variation underlines a haptodontine-grade or, less likely, sphenacodontid position for Tetraceratops


  Article infos

Published in Vol 43-1 (2020)

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Le genre Mesembriacerus (Bovidae, Artiodactyla, Mammalia) : un Oviboviné primitif du Vallésien (Miocène supérieur) de Macédoine (Grèce)
Geneviève Bouvrain and Louis de Bonis
Keywords: Bovidae; Cladistics; Late Miocene; Ovibovinae; Vallesian
 
  Abstract

    The bovid Mesembriacerus melentisi, the numerous skulls, teeth and limb bones of which are described from the locality Ravin de la Pluie (Macedonia, Greece), bears some features which allow us to put it in the tribe ovibovini (Ovibovinae) with several other Miocene genera and the Recent one Ovibos. A cladogram gives the phyletic relationships within this tribe. It shows that Mesembriacerus which is one of the oldest genera, is also the most primitive. The limb bones are as elongated as those of Recent cursorial bovids and they show, as does the bulk of the fauna, an open environment for the locality. 


  Article infos

Published in Vol. 14, Fasc. 4 (1984)

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Contributions à l'étude des micromammifères du gisement Miocène supérieur de Montredon (Hérault). 2- Les rongeurs
Jean-Pierre Aguilar
Keywords: Hérault; Late Miocene; Micromammals; Montredon; Rodents
 
  Abstract

    The recent excavation of the Upper Miocene locality of Montredon (Hérault) provides a rich material of Mammals. The present study deals with rodents. The new quarry is 10 meters above the classical Depéret's Quarry. No differences have been noticed between the rodent populations coming grom these two sites. The description of two new species : Hispanomys mediterraneus and Muscardinus heintzi is given and the dormouse Eliomys is recorded there for the first time. The new zonation of the Miocene given by Aguilar (1982) and the previously established correlations between marine and continental chronological scales give Tortonien age (estimated between 9 and 10 M.Y. old) to the site of Montredon, which belongs to the Mammal zone D 2. 


  Article infos

Published in Vol. 12, Fasc. 3 (1982)

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Rongeurs (Mammalia, Rodentia) du Miocène de Beni-Mellal
Jean-Jacques Jaeger
Keywords: Morocco; Neogene
 
  Abstract

    The rodent fauna of Beni-Mellal is characterized by the abundance of ctenodactylids and cricetids. The latter are represented by four distinct species, among which a new form. Dakkamys zaiani nov. gen., nov. sp. is described. A detailed morphological analysis shows that, contrary to that which had been established before, « Cricetodon ›› atlasi Lavocat, 1961, is not closely related to any European form known; this species is attributed, in consequence, to the new genus Mellalomys. A simple biometric analysis has shown that the genus Myocricetodon Lavocat, 1952, is represented in this locality by two distinct species. The systematic homogeneity of the Beni-Mellal cricetids is also demonstrated: they can, as a matter of fact, all be referred to the subfamily Myocricetodontinae. The definition of this subfamily is completed. The sciurids and glirids are also reviewed in the light of new systematic and biogeographic information established ln Europe. A new species of Atlantoxevus from the early Pleistocene of Morocco, A. huvelini nov. sp., is described. It is probably the descendant of A. tadlae from Beni-Mellal. Biogeographic analysis leads one to consider this fauna as the result of geographic isolation in the Maghreb since the late Oligocene or the early Miocene. In particular no direct European influence can be discerned. Stratigraphic considerations resulting from the discovery of new localities in North Africa lead to the confirmation of the ante-Vallesian age of this fauna and to its parallelism with the faunas of La Grive in Western Europe and Fort Ternan in East Africa. The peculiar geologic nature of this locality is discussed.
      


  Article infos

Published in Vol. 07, Fasc. 4 (1977)

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Les oiseaux aquatiques (Gaviiformes à Anseriformes) du gisement Aquitanien de Saint-Gerand-le-Puy (Allier, France): Révision systématique.
Jacques Cheneval
Keywords: Aves; Early Miocene; Osteology; Palaeoecology; Systematics
 
  Abstract

    Six orders of birds adapted to aquatic life are represented among the numerous avifauna of "Saint-Gérand-le-Puy": Gaviiformes, Procellariiformes, Pelecaniformes, Ciconiiformes, Phoenicopteriformes, and Anseriformes. The present study of this avifauna proposes several changes in systematics:- Procellariiformes: Puffinus arvernensis does not belong in Procellariidae but in Diomodeidae, and it is transferred to the fossil genus Plotornis previously described in the Middle Miocene of France. - Pelecaniformes: Phalacrocorax littoralis remains in Phalacrocoracidae; P. míocaenus is different from the modern species, and is transferred to the new genus Nectornis. Empheresula arvernensis, described in the Oligocene deposits of Gannat, seems to be present in Saint-Gérand-le-Puy too. Pelecanus gracilis shows many differences from the modern species, and belongs to the new genus Miopelecanus, - Ciconiiformes: Ardea formosa nom. oblit. is a synonym of Proardeola walkeri. - Anseriformes: a new species closely related to swans is described, and belongs to the fossil genus Cygnopterus, of the Middle Oligocene of Europe; this species is called C. alphonsi. The ecology of each species is suggested by comparison with that of its nearest living relatives, and by study of osteological adaptations. 


  Article infos

Published in Vol. 14, Fasc. 2 (1984)

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

    Abstract not available 


  Article infos

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

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Rongeurs caviomorphes de l'Oligocène de Bolivie. 1 Introduction au deseadien de Bolivie
Robert Hoffstetter
Keywords: Rodentia; South America
 
  Abstract

    The Tertiary of the Salla-Luribay basin consists of red beds affected by the second period of the andine compression, of Miocene ending age. The Tertiary layers are exposed at an approximate elevation of 3.500 to 4.000 meters. Two stratigraphic units can be distinguished in them: the Luribay conglomerates, in which vertical clifts result from erosion, and the Salla layers consisting mostly of consolidated clays. These clays are very fossiliferous and have furnished a rich vertebrate fauna which gave to R. Hoffstetter the possibility to establish the Oligocene age of these beds. Sediments of same age has been reported to be present in several other places of Bolivia, particularly near Lacayani, where have been collected highly hypsodont Rodents, different from those found in Salla-Luribay basin. 


  Article infos

Published in Vol. 07, Fasc. 3 (1976)

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An evening bat (Chiroptera: Vespertilionidae) from the late Early Eocene of France, with comments on the antiquity of modern bats
Suzanne J. Hand, Bernard Sigé, Michael Archer and Karen H. Black
Keywords: evolution; palaeobiogeography; Prémontré; Western Europe; Ypresian

doi: 10.18563/pv.40.2.e2
 
  Abstract

    Bats are among the most numerous and widespread mammals today, but their fossil record is comparatively meagre and their early evolution poorly understood. Here we describe a new fossil bat from dental remains recovered from late Early Eocene sediments at Prémontré, northern France. This 50 million-year-old bat exhibits a mosaic of plesiomorphic and apomorphic dental features, including the presence of three lower premolars, a single-rooted p3, short p4 with metaconid, myotodont lower molars and a tall coronoid process of the dentary. This combination of features suggests it is an early member of Vespertilionidae, today’s most speciose and geographically widespread bat family. The Prémontré bat has bearing on hypotheses about the origins of vesper or evening bats (Family Vespertilionidae), as well as crown-group chiropterans.


      


  Article infos

Published in Vol.40-2 (2016)

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A new species of bat (Chiroptera: Vespertilionidae) from the early Oligocene global cooling period, Brule Formation, North Dakota, USA
Nicholas Czaplewski, Jeff Person, Clint Boyd and Robert Emry
Keywords: Eocene-Oligocene global cooling; Mammalia; Oligocene; Plecotini; Quinetia

doi: 10.18563/pv.42.2.e2
 
  Abstract

    We report the first confirmed fossil bats from North Dakota, including a new species referable to the Vespertilionidae represented by a maxilla with P4-M3 from the Brule Formation, Fitterer Ranch local fauna, early Oligocene, Whitneyan North American Land Mammal Age. Unassociated postcranial fragments of the humerus and femur also represent a vespertilionoid, but appear to reflect a different, unidentified species. The new taxon, Quinetia frigidaria sp. nov., is referred to the genus Quinetia, previously known only from approximately contemporaneous deposits in Europe. The new species is larger than Quinetia misonnei from the early Oligocene of Belgium. It is similar in some morphological characters to Chadronycteris rabenae (Chiroptera incertae sedis) of the late Eocene (Chadronian) of northwestern Nebraska and to Stehlinia species (?Palaeochiropterygidae) from the Eocene and Oligocene of Europe, but differs from each in morphological details of the dentition and maxilla. An unassociated talonid of a lower molar from Fitterer Ranch shows myotodont morphology, unlike the nyctalodont lower molars in Q. misonnei, and thus represents a second chiropteran taxon in the fauna. Quinetia frigidaria is a member of a Paleogene radiation of bats near the low point of the Eocene-early Oligocene decline in global temperatures, increased seasonal aridity, and loss of tropical floras from mid-latitude North America. 


  Article infos

Published in Vol 42-2 (2019)

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Etude des dents jugales inférieures des Equus (Mammalia, Perissodactyla) actuels et fossiles
Véra Eisenmann
Keywords: Cheek teeth; Equus; Mammals
 
  Abstract

    The comparative morphology and biometry of the lower cheek teeth of modern Equus are studied on approximately 300 mandibles belonging to the 10 usually recognised species : Equus grevyi, E. burchelli, E. quagga, E. zebra, E. africanus, E. asinus, E. hemionus, E. klang, E. przewalskii, E. caballus. The studied parameters comprise : occlusal length and width, postflexid length and index ; shape of the double knot (metaconid + metastylid + lingual groove) ; depth of the vestibular groove on the molars ; frequency of the pli caballinid, protostylid and other enamel plications or islets ; frequency of the dP/l.
    The same methods of study are applied to a number of North American, Eurasian and African species. For the sake of comparison, some Hemphillian equids were observed (Dinohippus interpolatus, Dinohippus leidyanus, Astrohippus ansae, Phiohippus mexicanus) but most of the discussed material belongs to Pliocene or Pleistocene species of Equus : the « stenonine ›› E. stenonis, E. simplicidens, E. sanmeniensis and E. teilhardi; the « caballine ›› E. scotti, E. lambei, E. Iaurentius, E. mosbachensis, E. germanicus, E. gallicus, E. taubachensis and the Liakhov horse. The relationships of other species, in particular the North American E. calobatus, E. occidentalis, E. cf mexicanus are not clear for the moment. ln Africa, the Plio-Pleistocene species from Koobi Fora (Kenya) show some stenonine and perhaps asinine affinities. The relationships of E. numidicus and E. tabeti are uncertain but these species are probably related to the East African ones. E. mauritanicus is most certainly related to the Quagga group.
    The biometrical data are gathered in 32 tables ; 4 photographie plates and 19 figures illustrate the next. The whole is a complement of the previously published studies of the skulls, upper cheek teeth, incisors and metapodials of modern and fossil Equus.

      


  Article infos

Published in Vol. 10, Fasc. 3-4 (1981)

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Insectivores pliocènes du Sud de la France (Languedoc-Roussillon) et du Nord-Est de l'Espagne.
Jean-Yves Crochet
Keywords: Biostratigraphy; Insectivora; Languedoc; Pliocene; Spain; Systematics
 
  Abstract

    The first lists of Insectivores (Erinaceidae, Talpidae and Soricidae) from the Pliocene beds of Southern France and North-East Spain are given in this paper. The material from twelve localities is studied. These localities are geographically situated in Languedoc (Celleneuve, Vendargues, Nîmes, Sète, Balaruc 2 and Seynes), in Roussillon (Terrats, Serrats-d'en-Vacquer, Château d'eau and Mont-Hélène) and in North-East Spain (Layna, Medas Islands and Puebla de Valverde). These faunas correspond to the Early, Middle and Late Pliocene. 1 to 8 taxa are identified in these localities and 14 specific taxa are presently listed for this period in this area. Two new specific taxa are described as Galerix depereti nov. sp. from all the Early Pliocene localities in the North-Pyrenean area and as Desmanella gardiolensis nov. sp. from Balaruc 2. For this small mammals, two faunal assemblages are recognized. The first one is dated from the Early Pliocene (F 1, 2 and 3 zones in Aguilar et Michaux) and is characterized by Galerix depereti and rare and little diversified Soricids. The second one is Late Pliocene in age (zones G 2 and G 3). The fossils of the genus Talpa are relatively abundant and the Soricids are diversified and very abundant. The Middle Pliocene (zone G 1) is a transitional period. ln these faunas, most of the insectivore genera are known from the European Late Miocene beds (8 on 10). This fact demonstrates a relative continuity between the invectivore faunas from the Late Miocene to the Early Pliocene. In conclusion, somme paleoecological considerations are suggested.
      


  Article infos

Published in Vol. 16, Fasc. 3 (1986)

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Etude paléoneurologique comparative de Parabos Cordieri (De Christol), un bovidae (Mammalia, Artiodactyla) du Pliocène d'Europe Occidentale.
Catherine Gromolard
Keywords: Bovidae; endocranial cast; Europe; Pliocene
 
  Abstract

    A skull of Parabos cordieri, undamaged by fossilisation, allows us to make an endocranial cast, which is compared to those of Bos taurus, Boselaphus tragocamelus and Hippotragus equinus. These are studied by general form (shape, volume, « rolling-up›› and inclination), and by detailed morphology (gyri and sulci patterns, rete mirabile, importance of rhinencephalon and cerebellum).
    A preliminary study is made in order to recognize convolution topography, gyri, sulci, and the various encephalic regions as clearly on an endocranial cast as on a bare encephalon; an intermediate stage is the study of an encephalon covered with «soft» meninges.
    The comparative study reveals great similarity between the endocranial cast of Parabos cordieri and that of Boselaphus tragocamelus, both belonging to the tribe Boselaphini. On the other hand, a marked differences separates the cast of Parabos cordieri from that of Bos taurus, representing the tribe Bovini to which Parabos cordieri had been referred. The endocranial cast of Hippotragus equinus, which had long been considered the descendant of Parabos cordieri, is also quite different from that of Parabos


  Article infos

Published in Vol. 12, Fasc. 2 (1982)

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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
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). 


  Article infos

Published in Vol. 14, Ext (1984)

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