نتایج جستجو برای: middle eocene
تعداد نتایج: 158502 فیلتر نتایج به سال:
Larger benthic foraminifera (LBF) are common and diverse throughout the Paleogene sediments of southern Tanzania, but have previously been little studied. A recent programme of onshore drilling known as the Tanzania Drilling Project has recovered large proportion of this succession for palaeoclimatic and palaeontological study. The sediment is largely a hemipelagic clay with secondary gravity s...
An adult of a Ribbed Cocoon Maker Moth (Bucculatricidae) from Eocene Baltic amber is described as a new species (Bucculatrix rycki). This is the first description of a fossil adult of this microlepidopteran family, but previous evidence for this family comes from typical leaf mines in fossil leaves that provide evidence dating to the Upper Cretaceous. The minimal geological age for this adult s...
The enigmatic species Eolestes syntheticus Cockerell, 1940, from the Early Eocene of North America, previously attributed to the lestoid family Synlestidae, is re-examined in light of the discovery of new material from the Middle Eocene Kishenehn Formation in northwestern Montana. E. syntheticus and a new species, Eolestes ramosus sp. n., are attributed to a new family Eolestidae fam. n.. In ad...
چکیده ندارد.
Advanced eusociality sometimes is given credit for the ecological success of termites, ants, some wasps, and some bees. Comprehensive study of bees fossilized in Baltic amber has revealed an unsuspected middle Eocene (ca. 45 million years ago) diversity of eusocial bee lineages. Advanced eusociality arose once in the bees with significant post-Eocene losses in diversity, leaving today only two ...
Literature reports upper Cretaceous to Middle Eocene flysch/wildflysch deposits from Mexico, Guatemala, Jamaica, Cuba, Puerto Rico, Barbados, Granada, Trinidad, Venezuela, Colombia, Ecuador and Peru. Early papers recording their widespread distribution and noting their tectonic implications are often overlooked by popular palaeogeographic and plate tectonic reconstructions of the Caribbean area...
Sixteen new K-Ar dates are presented from Tasmanian and Bass Basin basalts, more than doubling the previously published number. Eight volcanic regions are described, based on boundaries established on the range of the basalt types contained in each geographic region. Volcanism occurred within the span from Eocene to Miocene (47 to 13+ Ma), but mainly within the time range Middle Eocene to Early...
Tropical South America has the highest plant diversity of any region today, but this richness is usually characterized as a geologically recent development (Neogene or Pleistocene). From caldera-lake beds exposed at Laguna del Hunco in Patagonia, Argentina, paleolatitude approximately 47 degrees S, we report 102 leaf species. Radioisotopic and paleomagnetic analyses indicate that the flora was ...
In this research, biostratigraphy related to the carbonate succession of the Shahbazan Formation at the southeastern flank of Chenar anticline, Lurestan Basin, is discussed. A study of large benthic foraminifera from the 294 mthick Shahbazan Formation led to the identification of two Middle Eocene biozones: Somalina sp. Zone, Nummulites-Alveolina Assemblage Zone. The age of the Shahbazan Format...
I n PNAS, Chaimanee et al. (1) report a previously undescribed species of primate, Afrasia, from the late Middle Eocene of Burma. They identify Afrasia as the sister taxon to the African genus Afrotarsius but slightly more primitive than it and allied with stem Anthropoidea of south Asia. Anthropoidea is the taxonomic group that today includes New and Old World monkeys, apes, and humans. If uph...
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