نتایج جستجو برای: late paleocene

تعداد نتایج: 196317  

2015
Nicholas J. Czaplewski Gary S. Morgan Kenneth De Baets

A new species of Apatemyidae, Sinclairella simplicidens, is based on four isolated teeth that were screenwashed from fissure fillings at the late Oligocene Buda locality, Alachua County, Florida. Compared to its only congener Sinclairella dakotensis, the new species is characterized by upper molars with more simplified crowns, with the near absence of labial shelves and stylar cusps except for ...

2009
Robert E. Kopp Dirk Schumann Timothy D. Raub David S. Powars Linda V. Godfrey Nicholas L. Swanson-Hysell Adam C. Maloof Hojatollah Vali

On the mid-Atlantic Coastal Plain of the United States, Paleocene sands and silts are replaced during the Paleocene-Eocene Thermal Maximum (PETM) by the kaolinite-rich Marlboro Clay. The clay preserves abundant magnetite produced by magnetotactic bacteria and novel, presumptively eukaryotic, iron-biomineralizing microorganisms. Using ferromagnetic resonance spectroscopy and electron microscopy,...

2012
Camilo Montes A. Cardona D. A. Ramírez N. Hoyos J. Wilson D. Farris

The rise of the Isthmus of Panama, linked to a number of climatic, paleoceanographic, and biological events, has been studied mostly from indirect, often distal, geochemical and biotic evidence. We have upgraded existing geologic mapping in central Panama with more than 2000 fi eld stations, over 40 petrographic analyses, and more than 30 new geochronological and thermo chrono logical analy ses...

2016
Sigisfredo Garnica Kai Riess Max E. Schön Franz Oberwinkler Sabrina D. Setaro

Patterns of geographic distribution and composition of fungal communities are still poorly understood. Widespread occurrence in terrestrial ecosystems and the unique richness of interactions of Sebacinales with plants make them a target group to study evolutionary events in the light of nutritional lifestyle. We inferred diversity patterns, phylogenetic structures and divergence times of Sebaci...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2015
Viviana D Barreda Luis Palazzesi Maria C Tellería Eduardo B Olivero J Ian Raine Félix Forest

The Asteraceae (sunflowers and daisies) are the most diverse family of flowering plants. Despite their prominent role in extant terrestrial ecosystems, the early evolutionary history of this family remains poorly understood. Here we report the discovery of a number of fossil pollen grains preserved in dinosaur-bearing deposits from the Late Cretaceous of Antarctica that drastically pushes back ...

Journal: :Smithsonian Contributions to Paleobiology 1999

2006
John A. Higgins Daniel P. Schrag

Extreme global warmth and an abrupt negative carbon isotope excursion during the Paleocene–Eocene Thermal Maximum (PETM) have been attributed to a massive release of methane hydrate from sediments on the continental slope [G.R. Dickens, J.R. O'Neil, D.K. Rea, R.M. Owen, Dissociation of oceanic methane hydrate as a cause of the carbon isotope excursion at the end of the Paleocene, Paleoceanograp...

Journal: :Fossil Record 2022

Morotodon aenigmaticus gen. et sp. nov. (Mammalia, Metatheria, ?Herpetotheriidae) from the early or early-middle Miocene of equatorial Africa (Moroto II locality, Moroto District, northeastern Uganda) is characterized by a short anterior cingulum, buccal shelf, well-developed hypoconulid in central position, and trigonid talonid with similar mesio-distal lengths. Its small size morphology sugge...

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