نتایج جستجو برای: Oligocene

تعداد نتایج: 2183  

2017
Paloma López-Guerrero Olivier Maridet Gudrun Daxner-Höck

The Oligocene fossil deposits from Valley of Lakes in Central Mongolia have provided a wealth of rodent fossils. Among these, cricetids are a very important part. To date, only the Miocene genera have been described in detail. Here, we focus on the Oligocene genus Eucricetodon from this region. Eucricetodontinae are the most abundant fossils in the Oligocene Valley of Lakes faunas. The present ...

2017
Olivier Maridet Gudrun Daxner-Höck Paloma López-Guerrero Ursula B Göhlich

The present publication reports new discoveries of Oligocene and early Miocene aplodontid rodents from the Taatsiin Gol area (Valley of Lakes) in Mongolia. The fossil aplodontids recovered in this area are mainly composed of dental remains, some fragmentary jaws plus one partially preserved skull. Aplodontid rodents have been found from the early Oligocene (local biozone A) to the early middle ...

2014
T. C. Moore Bridget S. Wade Thomas Westerhold Andrea M. Erhardt Helen K. Coxall Jack Baldauf Meghan Wagner

There is general agreement that productivity in high latitudes increased in the late Eocene and remained high in the early Oligocene. Evidence for both increased and decreased productivity across the Eocene-Oligocene transition (EOT) in the tropics has been presented, usually based on only one paleoproductivity proxy and often in sites with incomplete recovery of the EOT itself. A complete reco...

2017
Paloma López-Guerrero Olivier Maridet Gudrun Daxner-Höck

We describe the remains of Aralocricetodon Bendukidze, 1993; Bagacricetodon Gomes Rodrigues et al., 2012; Eocricetodon Wang, 2007; Witenia de Bruijn et al., 2003 and Paracricetodon Schaub, 1925 (Cricetidae, Rodentia, Mammalia) from the Taatsiin Gol and Taatsiin Tsagaan Nuur areas (Mongolia). The studied material (comprising 128 teeth) stems from 9 localities and 23 fossil layers spanning a time...

2007
Alessandro Zanazzi Matthew J. Kohn

To characterize the ecology and physiology of common late Eocene–early Oligocene White River mammals, we analyzed the carbon and oxygen isotope composition of tooth enamel carbonate for six of the most abundant taxa: the perissodactyls Brontops (brontothere), Mesohippus (equid) and Subhyracodon (rhino); and the artiodactyls Merycoidodon (oreodont), Leptomeryx (leptomerycid) and Poebrotherium (c...

Journal: :Biological reviews of the Cambridge Philosophical Society 2005
Gerald Mayr

The Paleogene (Paleocene-Oligocene) fossil record of birds in Europe is reviewed and recent and fossil taxa are placed into a phylogenetic framework, based on published cladistic analyses. The pre-Oligocene European avifauna is characterized by the complete absence of passeriform birds, which today are the most diverse and abundant avian taxon. Representatives of small non-passeriform perching ...

2016
Everett H. Lindsay Lawrence J. Flynn

A series of Oligocene through Early Miocene terrestrial deposits preserved in the foothills of the Zinda Pir Dome of western Pakistan produce multiple, superposed fossil mammal localities. These include small mammal assemblages that shed light on the evolution of rodent lineages, especially Muroidea, in South Asia. Nine small mammal localities span approximately 28-19 Ma, an interval encompassi...

2005
Bridget S. Wade Heiko Pälike

To document the evolution of the early cryosphere, stable isotope analyses were conducted on the planktonic and benthic foraminifers from Ocean Drilling Program Site 1218. We generated two parallel 54m-long records at 10-cm resolution and thus produced a standard Pacific stable isotope reference curve for the 26.4to 30.0-Ma interval within the Oligocene. These data are necessary to document the...

Journal: :Science 2005
Mark Pagani James C Zachos Katherine H Freeman Brett Tipple Stephen Bohaty

The relation between the partial pressure of atmospheric carbon dioxide (pCO2) and Paleogene climate is poorly resolved. We used stable carbon isotopic values of di-unsaturated alkenones extracted from deep sea cores to reconstruct pCO2 from the middle Eocene to the late Oligocene (approximately 45 to 25 million years ago). Our results demonstrate that pCO2 ranged between 1000 to 1500 parts per...

2015
Yunfa Chen Steven R. Manchester William Oki Wong

Deviacer guangxiensis Chen & Manchester sp. nov. is described based on asymmetric samaras from the Oligocene Ningming Formation in Guangxi, South China, representing the first documentation of Deviacer fossils in Asia. The Oligocene species, with relatively large fruits, represents the youngest record of the genus so far known; all other records are from the Paleocene and Eocene, or late Eocene...

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