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Wyszukujesz frazę "Late Pleistocene" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Osteoderm histology of Late Pleistocene cingulates from the intertropical region of Brazil
Autorzy:
Da Costa Pereira, P.V.L.G.
Victer, G.D.
Porpino, K.O.
Bergqvist, L.P.
Powiązania:
https://bibliotekanauki.pl/articles/945892.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
osteoderm
histology
Late Pleistocene
Pleistocene
Cingulata
mammalia
Glyptodontidae
Pachyarmatherium
paleohistology
intertropical region
Brazil
Opis:
During the Late Pleistocene, several possibly endemic cingulate species, known mostly from isolated osteoderms, carapace fragments, and caudal tubes, coexisted in the Brazilian Intertropical Region. Here, we describe the osteoderm microstructure of Pachyarmatherium brasiliense, as well as the glyptodonts Panochthus greslebini, Panochthus jaguaribensis and Glyptotherium sp., in order to provide additional species-diagnostic characters and shed light on their evolutionary relationships. Pachyarmatherium brasiliense lacks several derived features shared by glyptodonts and pampatheres, such as extensive bone remodeling, fibers arranged in large bundles, and relatively poorly developed layers of compact bone, thus supporting its exclusion from glyptodonts as suggested by a recent cladistic study. The osteoderm histology of P. greslebini resembles that of other species of Panochthus (e.g., Panochthus frenzelianus). By contrast, the presence of relatively thick layers of compact bone, the configuration and size of resorption areas, the absence of randomly oriented lateral fiber bundles, and the absence of an intermediary region between the compact and trabecular bone potentially support the exclusion of Panochthus jaguaribensis from the genus. Finally, osteoderms of the Brazilian specimens of Glyptodontinae share histological features with Glyptotherium floridanus, rather than Glyptodon, thus reinforcing their assignment to Glyptotherium. These results highlight the relevance of histological osteoderm characters in cingulate systematics, ands call for further and more comprehensive studies.
Źródło:
Acta Palaeontologica Polonica; 2014, 59, 3; 543-552
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Paleoecology of the large carnivore guild from the late Pleistocene of Argentina
Autorzy:
Prevosti, F.J.
Vizcaino, S.F.
Powiązania:
https://bibliotekanauki.pl/articles/23538.pdf
Data publikacji:
2006
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Carnivora
carnivore
Late Pleistocene
Pleistocene
South America
paleoecology
population density
Argentina
paleontology
fossil carnivore
locality
biomass
ecology
Opis:
The paleoecology of the South American fossil carnivores has not been as well studied as that of their northern relatives. One decade ago Fariña suggested that the fauna of Río Luján locality (Argentina, late Pleistocene–early Holocene) is not balanced because the metabolic requirements of the large carnivores are exceeded by the densities and biomass of the large herbivores. This conclusion is based on the calculation of densities using allometric functions between body mass and population abundance, and is a consequence of low carnivore richness versus high herbivore richness. In this paper we review the carnivore richness in the Lujanian of the Pampean Region, describe the paleoecology of these species including their probable prey choices, and review the available information on taphonomy, carnivore ecology, and macroecology to test the hypothesis of “imbalance” of the Río Luján fauna. The carnivore richness of the Río Luján fauna comprises five species: Smilodon populator, Panthera onca, Puma concolor, Arctotherium tarijense, and Dusicyon avus. Two other species are added when the whole Lujanian of the Buenos Aires province is included: Arctotherium bonariense and Canis nehringi. With the exception of D. avus and Arctotherium, these are hypercarnivores that could prey on large mammals (100–500 kg) and juveniles of megamammals (>1000 kg). S. populator could also hunt larger prey with body mass between 1000 and 2000 kg. The review of the “imbalance” hypothesis reveals contrary evidence and allows the proposal of alternative hypotheses. If high herbivore biomass occurred during the Lujanian, a higher density of carnivores could be supported than as inferred from the power function of body size and population density.
Źródło:
Acta Palaeontologica Polonica; 2006, 51, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A small camelid Hemiauchenia from the Late Pleistocene of Hidalgo, central Mexico
Autorzy:
Bravo-Cuevas, V.M.
Jimenez-Hidalgo, E.
Cuevas-Ruiz, G.E.
Cabral-Perdomo, M.A.
Powiązania:
https://bibliotekanauki.pl/articles/22741.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
small camelid
camelid
Hemiauchenia
Late Pleistocene
Hidalgo
Mexico
Camelidae
Pleistocene
paleontology
geological setting
systematics
mandible
dentition
postcranial bone
remains
tooth
fossil
Opis:
Pleistocene camels from Mexico include representatives of llamas and camels. Their record spans from the Early Blancan to the Late Pleistocene, based on several localities in the northern, northwestern and central parts of the country, with members of the genus Hemiauchenia being particularly well represented. New specimens of a small llama, collected in the state of Hidalgo, central Mexico, are assigned to Hemiauchenia gracilis owing to a combination of cranial and postcranial characters, including a short upper premolar−molar series, the presence of a two−rooted P3, molars covered by a thin layer of cementum, U−shaped molar crescents, well−developed styles and ribs, a small degree of crenulation, a relatively short lower tooth row, the lack of p1 and p3, weakly developed anteroexternal stylids, a shallow and slender mandible, and long and slender metatarsals and phalanges. The material described here extends the Pleistocene geographic distribution of H. gracilisfrom northern to central Mexico, and its biochronological range from the Early Blancan to the Late Pleistocene (Rancholabrean), thus making it the southernmost record and the geochronologically youngest occurrence of this species in North America. The mesowear pattern of the material from Hidalgo suggests that these animals were mainly browsers. Their estimated body mass resembles that of Blancan specimens from Guanajuato, implying that this species maintained approximately the same body mass throughout its biochronological range in central Mexico.
Źródło:
Acta Palaeontologica Polonica; 2012, 57, 3
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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