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Antoine P.-O.,Montpellier University | Antoine P.-O.,French National Center for Scientific Research | Marivaux L.,Montpellier University | Croft D.A.,Case Western Reserve University | And 13 more authors.
Proceedings of the Royal Society B: Biological Sciences | Year: 2012

The long-term isolation of South America during most of the Cenozoic produced a highly peculiar terrestrial vertebrate biota, with a wide array of mammal groups, among which caviomorph rodents and platyrrhine primates are Mid-Cenozoic immigrants. In the absence of indisputable pre-Oligocene South American rodents or primates, the mode, timing and biogeography of these extraordinary dispersals remained debated. Here, we describe South America's oldest known rodents, based on a new diverse caviomorph assemblage from the late Middle Eocene (approx. 41 Ma) of Peru, including five small rodents with three stem caviomorphs. Instead of being tied to the Eocene/Oligocene global cooling and drying episode (approx. 34 Ma), as previously considered, the arrival of caviomorphs and their initial radiation in South America probably occurred under much warmer and wetter conditions, around the Mid-Eocene Climatic Optimum. Our phylogenetic results reaffirm the African origin of South American rodents and support a trans-Atlantic dispersal of these mammals during Middle Eocene times. This discovery further extends the gap (approx. 15 Myr) between first appearances of rodents and primates in South America. © 2011 The Royal Society. Source


Antoine P.-O.,Montpellier University | Roddaz M.,French National Center for Scientific Research | Brichau S.,French National Center for Scientific Research | Tejada-Lara J.,National Major San Marcos University | And 8 more authors.
Journal of South American Earth Sciences | Year: 2013

A new middle Miocene vertebrate fauna from Peruvian Amazonia is described. It yields the marsupials Sipalocyon sp. (Hathliacynidae) and Marmosa (Micoureus) cf. laventica (Didelphidae), as well as an unidentified glyptodontine xenarthran and the rodents Guiomys sp. (Caviidae), " Scleromys" sp., cf. quadrangulatus-schurmanni-colombianus (Dinomyidae), an unidentified acaremyid, and cf. Microsteiromys sp. (Erethizontidae). Apatite Fission Track provides a detrital age (17.1 ± 2.4 Ma) for the locality, slightly older than its inferred biochronological age (Colloncuran-early Laventan South American Land Mammal Ages: ~15.6-13.0 Ma). Put together, both the mammalian assemblage and lithology of the fossil-bearing level point to a mixture of tropical rainforest environment and more open habitats under a monsoonal-like tropical climate. The fully fluvial origin of the concerned sedimentary sequence suggests that the Amazonian Madre de Dios Subandean Zone was not part of the Pebas mega-wetland System by middle Miocene times. This new assemblage seems to reveal a previously undocumented " spatiotemporal transition" between the late early Miocene assemblages from high latitudes (Patagonia and Southern Chile) and the late middle Miocene faunas of low latitudes (Colombia, Perú, Venezuela, and ?Brazil). © 2012 Elsevier Ltd. Source


Antoine P.-O.,Montpellier University | Billet G.,CNRS Center for Research on Palaeobiodiversity and Palaeoenvironments | Salas-Gismondi R.,Montpellier University | Salas-Gismondi R.,National Major San Marcos University | And 7 more authors.
Journal of Mammalian Evolution | Year: 2015

In spite of a scarce fossil record and poor diversity, xenungulates cover a wide spatial range throughout South America: a new representative of Carodnia Simpson, 1935, attests to the northernmost occurrence of a carodniid xenungulate, ~4,500km away from previous occurrences (Saõ José de Itaboraí, Rio de Janeiro, Brazil; Chubut Province, Patagonia, Argentina) and very close to the Pacific Coast. A phylogenetic analysis of Xenungulata at the species level shows that Xenungulata and Carodniidae are monophyletic, while Etayoidae are potentially paraphyletic, at least with the selected taxonomic sample. Phylogenetic relationships among Xenungulata are [Notoetayoa gargantuai, Etayoa bacatensis [Carodnia sp. nov. [Carodnia feruglioi, C. cf. feruglioi, C. vieirai]]]. The new species is well differentiated from other xenungulates in having the m3 slightly smaller than m2 in terms of occlusal area and the entoconid and hypoconid almost at the same level on m3. It further differs from all other xenungulates but Etayoa bacatensis in possessing a transverse protolophid on m3. It is distinct from all other representatives of Carodnia in showing a precingulid strongly developed on m2-m3. Referral of the locality to the well-constrained early Eocene Mogollón Formation also confirms (i) the persistence of both carodniid and etayoid xenungulates well after the Paleocene-Eocene transition in South America and (ii) the absence of paleogeographic barrier for such large terrestrial mammals at the scale of South American landmass. © 2014, Springer Science+Business Media New York. Source


Pujos F.,CONICET | Pujos F.,Institute Francais dEtudes Andines | De Iuliis G.,University of Toronto | De Iuliis G.,Royal Ontario Museum | Quispe B.M.,Museo Nacional de Historia Natural
Journal of Vertebrate Paleontology | Year: 2011

A dentary from the Laventan SALMA (middle Miocene) of Quebrada Honda, Bolivia, recognized as a new, small member of Megatherioidea (Hiskatherium saintandrei, gen. et sp. nov.), is reported. This taxon is clearly distinct from Nothrotheriidae and Megalonychidae and has affinities with Hapalops and Xyophorus. It is characterized by m1-m4 without diastema; strong hypsodonty (HI = 0.93); m1-m3 constituted by two transverse lophids separated by a deep, transverse, and labially open valley; m4 round with distal lophid mesiolingually-distolabially extended and without vertical groove; m2-m3 with lingual and labial vertical grooves; and the posteroventral margin of symphysis located anteriorly to m1. Although Hiskatherium and Diabolotherium have a similar dental formula, the 'megatheriine-shaped' teeth of Diabolotherium do not support a close phylogenetic relationship between Hiskatherium and Diabolotherium. Their dental formulae suggest that both genera were selective feeders, capable of consuming tough items. Hiskatherium, like most other sloths, has lower molariform teeth that have a mesial and a distal lophid; the former has a mesial cuspid 'A,' located at the center of the mesial lophid, and the latter has distolingual ('B,' or lingual) and distolabial ('C') cuspids at each end. This terminology permits a straightforward nomenclature based on cusp/cuspid position and facilitates comparisons among Tardigrada. © 2011 by the Society of Vertebrate Paleontology. Source


Goillot C.,University Paul Sabatier | Antoine P.-O.,University Paul Sabatier | Tejada J.,National Major San Marcos University | Tejada J.,Institute Francais dEtudes Andines | And 3 more authors.
Geodiversitas | Year: 2011

Five mandibular and dental specimens referred to the extinct South American ungulate clade Astrapotheria are described. They originate from late middle Miocene deposits of the Ipururo Formation in the Río Inuya-Río Mapuya area, Peruvian Amazonia. The first Peruvian astrapothere remains unearthed in a controlled stratigraphical context reveal the co-occurrence of the uruguaytheriine astrapotheriids Xenastrapotherium sp. and Granastrapotherium cf. snorki. Bispecific uruguaytheriine assemblages were so far restricted to the early Miocene of Venezuela and the late middle Miocene of Colombia. The Fitzcarrald local fauna, including the uruguay theriines described here, recalls unequivocally the Xenastrapotherium kraglievichi Cabrera, 1929-Granastrapotherium snorki assemblage, which characterizes the 13.6-12.76 Ma interval in the Honda Group of La Venta area, Colombia. The spatio-temporal distribution of low-latitude astrapotheriids (< 30°S) is then reviewed, illustrated, and further detailed in both stratigraphical and taxonomic points of view. The group appears in the fossil record during the Oligocene or the earliest Miocene (Uruguaytherium Kraglievich, 1928 and Xenastrapotherium Kraglievich, 1928 in Uruguay and Venezuela, respectively). Uruguaytheriinae are conspicuous elements of middle Miocene mammal assemblages of northern South America (Colombia, Brazil, Bolivia, and now Peru). Astrapotheria probably become extinct during the late Miocene (Huayquerian South American Land Mammal Age), but the youngest specimens are of uncertain taxonomic affi nities and/or might be reworked (Astrapotheriidae indet. in Urumaco Formation of Venezuela;? Astrapotheria in Rio Acre local fauna of Brazil). © Publications Scientifiques du Muséum national d'Histoire naturelle, Paris. Source

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