نتایج جستجو برای: paleogene

تعداد نتایج: 1290  

2016
Roger B. J. Benson Richard J. Butler John Alroy Philip D. Mannion Matthew T. Carrano Graeme T. Lloyd Anthony D. Barnosky

How did evolution generate the extraordinary diversity of vertebrates on land? Zero species are known prior to ~380 million years ago, and more than 30,000 are present today. An expansionist model suggests this was achieved by large and unbounded increases, leading to substantially greater diversity in the present than at any time in the geological past. This model contrasts starkly with empiri...

2007
Barbara J.

The northwestern Gulf of Mexico basin has emerged as an archetype example of a robust, progradational passive margin system that induces substantial translation over underlying detachments due to gravitational loading. Despite this recognition, the difficulties in deep imaging of seismic data have continued to obscure key features of this deformation. Megaregional, 2D, long-offset PSDM data hel...

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 ...

Journal: :Journal of Geoscience, Engineering, Environment, and Technology 2016

2017
Sanaa E El-Sayed Mahmoud A Kora Hesham M Sallam Kerin M Claeson Erik R Seiffert Mohammed S Antar

Wadi El-Hitan, the UNESCO World Heritage Site, of the Fayum Depression in the northeast part of the Western Desert of Egypt, has produced a remarkable collection of Eocene vertebrates, in particular the fossil whales from which it derives its name. Here we describe a new genus and species of marine catfishes (Siluriformes; Ariidae), Qarmoutus hitanensis, from the base of the upper Eocene Birket...

2017
Matthew R Borths Nancy J Stevens

Throughout the Paleogene, most terrestrial carnivore niches in Afro-Arabia were occupied by Hyaenodonta, an extinct lineage of placental mammals. By the end of the Miocene, terrestrial carnivore niches had shifted to members of Carnivora, a clade with Eurasian origins. The transition from a hyaenodont-carnivore fauna to a carnivoran-carnivore fauna coincides with other ecological changes in Afr...

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