The long-term warmth of the Eocene (~56 to 34 million years ago) is commonly associated with elevated partial pressure of atmospheric carbon dioxide (pCO(2)). However, a direct relationship between the two has not been established for short-term climate perturbations. We reconstructed changes in both pCO(2) and temperature over an episode of transient global warming called the Middle Eocene Climatic Optimum (MECO; ~40 million years ago). Organic molecular paleothermometry indicates a warming of southwest Pacific sea surface temperatures (SSTs) by 3° to 6°C. Reconstructions of pCO(2) indicate a concomitant increase by a factor of 2 to 3. The marked consistency between SST and pCO(2) trends during the MECO suggests that elevated pCO(2) played a major role in global warming during the MECO.
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http://dx.doi.org/10.1126/science.1193654 | DOI Listing |
Introduction Raoellidae are small artiodactyls retrieved from the middle Eocene of Asia (ca - 47 Ma) and closely related to stem Cetacea. Morphological observations of their endocranial structures allow for outlining some of the early steps of the evolutionary history of the cetacean brain. The external features of the brain and associated sinuses of Raoellidae are so far only documented by the virtual reconstruction of the endocast based on specimens of the species Indohyus indirae.
View Article and Find Full Text PDFOne new extinct genus and six new extinct species of Zopheridae are described and illustrated from Eocene Baltic amber: Usechus andrushchenkoi Alekseev et Bukejs sp. nov., Coxelus carstengroehni Alekseev et Bukejs sp.
View Article and Find Full Text PDFSci Rep
November 2024
Institute of Geosciences, Goethe University Frankfurt, Frankfurt, Germany.
J Hum Evol
December 2024
Department of Anatomy, Des Moines University, 8025 Grand Ave, Des Moines, IA, 50266, USA. Electronic address:
The transition between the Bridgerian and Uintan North American Land Mammal Ages of the middle Eocene is a pivotal time in the evolution of modern mammal ecosystems in North America, marking the beginning of a global cooling trend that led to the recession of tropical forests and gradual faunal turnover on the continent. However, few mammalian faunas are known from this time period, leading to difficulty characterizing and recognizing early Uintan faunal assemblages. The Sand Wash Basin in northwestern Colorado has been suggested to yield fossil faunas of early Uintan age, but fossils from the Sand Wash Basin have not been formally described since the 1970s despite active field work in the region.
View Article and Find Full Text PDFEcol Evol
November 2024
Beijing Key Laboratory for Forest Pest Control, College of Forestry Beijing Forestry University Beijing China.
Pine stem rust, the most damaging and widespread forest disease occurring in pine trees in the Northern Hemisphere, is primarily caused by species (Pucciniales, Melampsorineae). While the phylogenetic relationships of major species have been largely elucidated, there is limited understanding of their species diversity and the evolutionary processes shaping their distribution patterns. In this work, we performed broad sampling and sequencing of taxa in China together with additional sequence data and other accessions in NCBI to investigate the diversification and to estimate the divergence time of major evolutionary events in this genus.
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