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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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A new Ardynomys (Rodentia,Cylindrodontidae) from the Eocene of the eastern Gobi Desert, Mongolia.
Demberelyin Dashzeveg
Keywords: Ardynomys; Eocene; Mongolia; Rodentia; Systematics
 
  Abstract

    A partial skull of Ardynomys russelli sp. nov. (Rodentia, Cylindrodontidae) is described. This was collected in the late Eocene of Alag Tsab locality in the eastem Gobi Desert, Mongolia. Ardynomys russelli sp. nov. is characterized by small size, brachyodont molars, and retention of P3. It represents the earliest record of the genus Ardynomys MATTHEW & GRANGER, 1925, in Asia. 


  Article infos

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

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La poche à phosphate de Ste-Néboule (Lot) et sa faune de vertebres du Ludien supérieur. 12- Fissipèdes (Carnivores)
Louis de Bonis
Keywords: Carnivora; Eocene; Quercy Phosphorites
 
  Abstract

    Les Carnivores Fissipèdes de Sainte-Néboule appartiennent tous au genre Cynodictis et semblent constituer une population homogène. Celle-ci se distingue suffisamment des espèces déjà décrites pour constituer un taxon particulier : Cynodictis lacustris neboulensis n. s. sp. . L'étude des variations à l'intérieur de cette population nous a conduit à reconsidérer les critères utilisés pour définir les espèces existantes et à regrouper certaines d'entre elles. Il semble qu'il demeure cependant trois lignées distinctes dans le genre Cynodictis mais le matériel nous paraît encore insuffisant pour traduire cette remarque en termes de systématique. 


  Article infos

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

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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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Les rongeurs de l'Oligocène inférieur d'Escamps
Monique Vianey-Liaud
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. 


  Article infos

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

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A new species of Propalaeotherium (Palaeotheriidae, Perissodactyla, Mammalia) from the Middle Eocene locality of Aumelas (Hérault, France).
Jean-Albert Remy, Gabriel Krasovec and Bernard Marandat
Keywords: Eocene; new species; Palaeotheriidae; Propalaeotherium

doi: 10.18563/pv.40.2.e1
 
  Abstract

    A new Propalaeotherium species, clearly distinct from the genus Eurohippus, is described. It is characterized by having a similar size as P. voigti from the German Geiseltal localities (MP 11 to MP 13 reference-level), but differs in several features suggesting a slighty more derived morphology. It presents indeed less brachyodont crowns with less prominent and less elevated cingula, slightly larger relative surface of premolars, and a more marked metaconid splitting on cheek teeth. This new species is unknown from other European localities except the nearby Saint-Martin de Londres locality which has been considered older than the MP 13 level. 


  Article infos

Published in Vol.40-2 (2016)

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S.I. Data
Les rongeurs de Chéry-Chartreuve et Rocourt-Saint-Martin (est du bassin de Paris; Aisne, France). Leur place parmi les faunes de l'Eocène Moyen d'Europe
Bernard Comte, Maurice Sabatier and Monique Vianey-Liaud
Keywords: Biochronology; evolution; Middle Eocene; Paris basin; Rodents; Systematics

doi: 10.18563/pv.37.4-5.167-271
 
  Abstract

    This paper is mainly devoted to the systematics of rodents from two middle Eocene (Bartonian) localities: Chéry-Chartreuve and Rocourt-Saint-Martin (Aisne, Eastern Paris Basin). These two localities are stratigraphically located slightly above the Auversian sands. The two faunas, which comprise 11 and 8 taxa, respectively, are very different in their composition. That of Rocourt-Saint-Martin shows strong similarities with that of the geographically very close locality of Grisolles, referred to the MP16 mammalian Reference level. The very distinct fauna of Chéry-Chartreuve includes a new species of Ailuravinae, Ailuravus nov.sp, and some teeth of the theridomyid Protadelomys, which represent archaic elements in the fauna. The most abundant species of the locality represents a new genus of primitive Theridomyidae. The presence of some teeth belonging to a new species of large Remyinae, Remys nov. sp., of Elfomys engesseri HOOKER & WEIDMANN, and a population of small dimensions referred to the genus Estellomys allow a correlation with Les Alleveys (Switzerland), with however some differences that would indicate an older age for Chéry-Chartreuve. Situated at the base of the "Marinesian" from the Bassin de Paris, this fauna is unquestionably different from those referred to the MP16 reference level and could represent an older level for which the macrofauna remains very poorly known. Conversely, the comparison of rodents from La Livinière II with those present in MP16 faunas, especially those of Robiac (Gard), shows a great similarity between both localities. This casts doubts on whether to keep this La Livinière II faunule to define the current MP15 reference level, while the biostratigraphical position of Pontils 26 (Spain), previously referred to this level, is reconsidered. Chery Chartreuse could be a good candidate for a new definition of the MP15 reference level. 


  Article infos

Published in Vol. 37, Fasc. 4-5 (2012)

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Mammals of the Eocene locality Toru Ajgyr (Kyrgyzstan)
Jorg Erfurt and Alexander Averianov
Keywords: Eocene; Kyrgyzstan; Mammalia; Olsenia; Palaeoecology; Stratigraphy; taxonomy
 
  Abstract

    Morphological descriptions are given of Eocene mammals from the locality Toru Ajgyr (NEKyrgyzstan) that were excavated in 1997 and 1998 in a cooperation between the Martin-Luther-University Halle (Germany), the Zoological Institute in St. Petersburg (Russia) and the Seismological Institute in Bishkek (Kyrgyzstan). The species found belong mostly to perissodactyls, as Lophialetes sp., Teleolophus sp. and brontotheres. The primitive ungulate family Olseniidae is represented by a complete foot skeleton of cf. Olsenia sp. In addition, postcranial materials of Gobiatherium mirificum (Dinocerata) and of artiodactyls have been collected and are described herein. Based on mammals, the locality is part of the Asian Land Mammal Age Arshantan and is stratigraphically equivalent with the Bridgerian Land Mammal Age in North America and with the lower and middle Geiseltalian of the European Middle Eocene. 


  Article infos

Published in Vol. 34, Fasc. 3-4 (2006)

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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 stratigraphic sequence of North American rodent faunas
Robert W. Wilson
Keywords: North America; Rodents; Stratigraphic sequence
 
  Abstract

    Rodents first appear in the latest Paleocene or earliest Eocene as very fragmentary specimens (Family Paramyidae) known largely from a single locality. After this sparse beginning, rodents are usually abundant in the North American record if proper recovery methods are used. Utilization of rodents for biostratigraphic purposes depends on 1/ extinction, and 2/ replacement by evolution of endemic groups and/or incursions of Old World rodents, and rarely and late by South American kinds. These incursions are separated by relatively long periods of isolation in the Paleogene, but more episodic in the Neogene. At least 10 rodent zones can be characterized by major distinctions, and these zones can be amplified into as many as 16 with little trouble. In general, rodent genera permit as refined a zonation as do genera of large mammals. Distinction at a specific level has not been attempted herein except in the Blancan and Post-Blancan. 


  Article infos

Published in Vol. 9, Ext (1980)

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A pangolin (Manidae, Pholidota, Mammalia) from the French Quercy phosphorites (Pech du Fraysse, Saint-Projet, Tarn-et-Garonne, late Oligocene, MP 28)
Jean-Yves Crochet, Lionel Hautier and Thomas Lehmann
Keywords: Oligocene; Pangolin; Pech du Fraysse; Quercy Phosphorites

doi: 10.18563/pv.39.2.e4
 
  Abstract

    Pangolins have never shown a high taxic diversity and their fossil record is scarce. We report here the first discovery of a partial humerus from late Oligocene deposits in Pech du Fraysse (MP28, France). The new specimen from Pech du Fraysse is described and compared to various extant and extinct species of pangolins. It shows a suite of morphological features very similar to the humeri discovered in Saint-André (MP 26), Solnhofen (Burdigalien), and Saulcet (Aquitanian), attributed here to Necromanis franconica. The description of the specimen from Pech du Fraysse allowed us to discuss the systematics of Paleogene and Neogene pholidotans. The differences between PFY 4051 and N. franconica on the one side, and N. quercyi on the other side, might be sufficiently important to justify a generic distinction. A comparison with extant species showed that N. franconica was likely terrestrial and fossorial based on its humeral morphology. 



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  Article infos

Published in Vol.39-2 (2015)

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Additions to the elasmobranch fauna from the upper Cretaceous of New Jersey (middle Maastrichtian, Navesink Formation)
Gerard R. Case and Henri Cappetta
Keywords: Elasmobranchs; New Jersey; new species; Upper Cretaceous; USA
 
  Abstract

    A recently discovered, almost complete specimen of a hybodont tooth, allows us to describe as a new species, fairly common, but usually fragmentary teeth in the Navesink Formation of New Jersey: Hybodus novojerseyensis nov. sp.
    Three additional taxa are also described : Heterodontus creamridgensis, Squalicorax sp. and Pseudocorax affinis which is noted for the first time in North America.
    The whole elasmobranch fauna of the Early Maastrichtian localities of New Jersey is reevaluated and several generic assignments are changed in comparison to the list previously published in 1975 (Cappetta
    & Case). 


  Article infos

Published in Vol. 33, Fasc. 1-4 (2004)

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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
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


  Article infos

Published in Vol. 13, Ext (1983)

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Systematic and evolutionary relationships of the hipparionine horses from Maragheh, Iran (Late Miocene, Turolian age)
Raymond L. Bernor
Keywords: evolution; Hipparionine horses; Iran; Systematics; Turolian
 
  Abstract

    A systematic analysis of an hipparionine horse assemblage from Maragheh, Iran is made. A brief orientation to systematic philosophy and informal superspecific characterizations of some Old World hipparionines is given as a background to this work. A character state analysis of skulls is made, and has revealed five distinct species. A character state and stratigraphic trend analysis of isolated check tooth and postcranial remains, with known provenance, is also made. These two combined analyses reveal that the most resolute discrimination of hipparionine species and their evolutionary relationships occurs when multiple character complexes of associated skulls, maxillary and mandibular dentitions are made. When this is not possible, skulls have provided the best basis for discriminating species and their evolutionary relationships. Traditional characters of isolated cheek teeth and postcranial remains are shown here to offer limited information content for hipparionine phylogenetic systematics. The systematic portion of this study includes a comprehensive description of cranial and postcranial remains, and has further corroborated the distinction of five species which belong to at least three superspecific groups including: «Hipparion» geltyi sp. nov., Group 1; Hipparion prostylum (s. l.), and Hipparion campbelli sp. nov., Group 3; «Hipparíon» aff. moldavicum and «Hipparion» ?matthewi, Group 2. These species stratigraphic ranges and evolutionary relationships are also given here and argued to be important for establishing future hipparionine geochronologic correlations between a number of Eurasian late Miocene provinces. 


  Article infos

Published in Vol. 15, Fasc. 4 (1985)

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Cryptomerix Schlosser, 1886, Tragulidé de l'oligocène d'Europe ; relations du genre et considérations sur l'origine des ruminants.
Jean Sudre
Keywords: Archaic Ruminants; Paleobiogeography; Quercy Phosphorites; Systematics; Tragulids
 
  Abstract

    The genus Cryptomeryx SCHLOSSER, 1886, inusited during a long period, has been discovered in Lower and Middle Oligocene localities of the Quercy region (South-West France). This new material, as well as specimens from the old collections referred to Cryptomeryx, are described; their study, allows us precising the definition of the genus, and confirming its allocation to the Tragulidae family. The type species of the genus, Crypmmeryx gaudryi (= Lophiomeryx gaudryi FILHOL, 1877), occurs in several localities at the base of the Middle Oligocene (Itardies, La Plante 2, Roqueprune 2, Soulce, Herrlingen 1). The new species C. matsoui n. sp. has been defined in the older locality of Mas de Got (top of Lower Oligocene). It is possible that the species Pseudamphimeryx decedens STEHLIN, 1910 pertains to the same genus. Also to the Tragulids must be referred the monospecific genus Iberomeryx (I. parvus GABOUNIA, 1964) from Upper Oligocene of Benara (Georgie, URSS), with which Cryptomeryx is related. These genera are not direct ancestors of Miocene tragulids; their occurrence in the Western European Oligocene results from a first immigration wawe of the family. These Tragulids are one of the most archaic groups of Ruminants. They are probably derived from a primitive stock which had acquired in Asia the selenodont condition of the dentition. 


  Article infos

Published in Vol. 14, Fasc. 1 (1984)

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Critical comments on the genus Propachynolophus Lemoine, 1891 (Mammalia, Perissodactyla, Equoidea)
 
Jean-Albert Remy
Keywords: Eocene; Eurohippus; Pachynolophus; Propalaeotherium; tooth morphology

doi: 10.18563/pv.41.1.e3
 
  Abstract

    Abstract
     The validity of Propachynolophus Lemoine, 1891, supposedly an intermediate between Hyracotherium Owen, 1841 and Pachynolophus Pomel, 1847, has been questioned for a long time. A detailed analysis of features on which this genus is based further supported by a formal cladistic analysis demonstrates that Propachynolophus is not a valid taxon. The type species, “Propachynolophus gaudryi Lemoine, 1891” shall be assigned to Propalaeotherium Gervais, 1849, under the new combination Propalaeotherium gaudryi (Lemoine, 1891). “Pachynolophus maldani Lemoine, 1878”, later assigned to Propachynolophus, typifies the new genus Orolophus, under the binomen Orolophus maldani (Lemoine, 1878). The other referred species, “Propachynolophus levei Hooker, 1994” and “P. remyi Checa-Soler, 1997” are poorly documented, and both species shall be provisionally referred to as “Hyracotherium levei (Hooker, 1994) and “Hyracotherium remyi (Checa-Soler, 1997), pending new discoveries.
     
      


  Article infos

Published in Vol 41-1 (2018)

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S.I. Data
Revision of the family Cephalomyidae (Rodentia, Caviomorpha) and new cephalomyids from the early Miocene of Patagonia.
Alejandro Kramarz
Keywords: Cephalomyidae; Lower Miocene; Patagonia; Rodentia; Soriamys; Systematics
 
  Abstract

     A new genus of hystricognath rodent with two new species, Soriamys gaimanensis and Soriamys ganganensis, from the Colhuehuapian Age (Early Miocene), Sarmiento Formation, of Patagonia is described. The first species comes from the south barranca of the valley of Rio Chubut, near Gaiman locality (Chubut Province). It is known through a great number of dental remains in different stages of wear. The teeth are protohypsodont, with cement in the principal valleys. P4 are simpler, more oval inoutline and without a differentiated hypocone-hypoflexus. Upper molars are pentalophodont in early stages of wear and become bilobated in middle and advanced stages; M3 have a temporary third posterior lobe due to the maintenance of the braquiflexus on the posterior wall of the tooth. Lower teeth have a completely asymrnetrical pattern in relation to the uppers. The molars are trilophodont, with only one complex crest in the trigonid composed of the fusion of the anterolophid and mesolophid. The dp4 have a derived pentalophodont pattern due to the loss or fusion of the mesolophid and the development of an accessory transverse crest between the anterolophid and metalophid. The second species is known through a complete skull and jaw and other skull fragments with the dentition, proceeding from Pampa de Gan Gan, Chubut province. Respect to the first species, the teeth are higher crowned, with an earlier occlusal simplification and a third posterior lobe of M3 more developed and persistent. The skull and jaws show many chinchilloid characters, such as jugal bone with an ascending process, concave palate, very prominent dorsal shelf of the masseteric fossa, nasolachrymal duct opened laterally on the maxillary and very developed lateral mandibular fossa. Moreover, Soriamys is closely related to Cephalomys by sharing a similar asymmetric dental pattern and other dental and mandibular characters. These two genera constitute a natural group, the Cephalomyidae, with peculiar dental characters, like the asymmetric pattem of the upper and lower teeth; Cephalomyopsis, and probably Litadontomys, can be considered part of this group. Scotamys and Perimys constitute a distinct lineage (the Neopiblemidae or Perimyidae), more closely related to the chinchillids. Many characters shared by cephalomyids, eocardiids and caviids suggest a closer affinity between the Chinchilloidea and the Cavioiidea as a whole. Abrocoma shows also an asymmetric dental pattern and other chinchilloid features that suggest some degree of relationship with the cephalomyids, still not well determined. 


  Article infos

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

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Analysis of mammalian communities from the late Eocene and Oligocene of southern France
Serge Legendre
Keywords: Late Eocene; Mammalian communities; Oligocene; Quercy; Southern France
 
  Abstract

    Valverde's cenogram method is used to analyse mammalian communities from the late Eocene to late Oligocene of southern France, mainly from the "Phosphorites du Quercy". Cenogram analysis involves plotting the size of each component species in a fauna on a semilog diagram in rank order, permitting fossil faunas to be compared with Recent ones. The configurations of Recent communities serve as models for establishing the general environmental characteristics of fossil mammalian faunas. This method of analysis applied to faunal sequence can reveal major and sudden ecological perturbations. The paleobiogeographical event (i.e. the mammalian immigration wave) at the Eocene-Oligocene Boundary in western Europe, known as the «Grande Coupure", is here shown to represent a drastic and sudden ecological change: late Eocene tropical environments in Europe deteriorated rapidly turning to subdesert or desert environments al the beginning of the Oligoccne. 


  Article infos

Published in Vol. 16, Fasc. 4 (1986)

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Les rongeurs de l'Eocène d'Afrique Nord-Occidentale [Glib Zegdou ( Algérie) et Chambi (Tunisie)] et l'origine des anomaluridae.
Monique Vianey-Liaud, Jean-Jacques Jaeger, Jean-Louis Hartenberger and Mahammed Mahboubi
Keywords: Africa; Eocene; New taxa; Paleobiogeography; PHYLOGENY; Rodents
 
  Abstract

    This paper is about the oldest African rodents faunas, from the late Early Eocene, or early Middle Eocene, Glib Zegdou (Algeria) and Chambi (Tunisia) localities. Five species are described and figured, belonging to a new family here created, the Zegdoumyidae.

    This family is compared to the Early and Middle Eocene rodents families from Asia, Europe and North America (Chapattimyidae, Yuomyidae, Gliridae, Theridomyidae, lschyromyidae and Sciuravidae), as well as to those known from the Late Eocene African locality Bir El Ater (Anomaluridae and Phiomyidae).

    On the one hand, it seems clear that the African endemic Anomaluridae arise from the Zegdoumyidae. On the other hand, the lschyromyidae, or primitive Sciuravidae, may be the most reliable ancestral groups for the Zegdoumyidae. Thus, this new family can be considered as the sister group for the American Sciuravidae on the one hand, and for the European Gliridae on the other hand.

    The biogeographical consequences of these phylogenetic hypotheses are discussed. A new phase of communication between Europe and North Africa is inferred, during the Early Eocene. It has been followed by a short period of endemism, allowing the adaptive radiation for the Zegdoumyidae, preceding the immigration of the Phiomyidae, during the Late Eocene, probably from Asian relatives. 


  Article infos

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

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Preliminary evolution of paleosols and implications for interpreting vertebrate fossil assemblages, Kuldana formation, Northern Pakistan
Andres Aslan and J. G. M. Thewissen
Keywords: Eocene; Kuldana Formation; Pakistan; Paleosols; Pedogenic Carbonate; taphonomy; Time Averaging; Vertebrate Fossils
 
  Abstract

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


  Article infos

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

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