نتایج جستجو برای: fossils
تعداد نتایج: 14159 فیلتر نتایج به سال:
Early Cretaceous body and trace fossils in Victoria, Australia, establish the oldest known presence of parastacid crayfish (Decapoda: Astacidea, Parastacoidea) in freshwater environments of Australia, and the oldest known crayfish in Gondwana. Parastacid body fossils, comprised of a partial abdomen (Palaeoechinastacus australianus, gen. et sp. nov.) and two chelae, are from a fluvial deposit in...
Elucidating cardiac evolution has been frustrated by lack of fossils. One celebrated enigma in cardiac evolution involves the transition from a cardiac outflow tract dominated by a multi-valved conus arteriosus in basal actinopterygians, to an outflow tract commanded by the non-valved, elastic, bulbus arteriosus in higher actinopterygians. We demonstrate that cardiac preservation is possible in...
The Orussidae is a small and rare but phylogenetically important family of parasitoid wasps. The fossil record of the family is also very poor. Baltorussus velteni was described from Baltic amber from an allegedly female specimen. This and another recently discovered specimen are examined with microCT scanning and standard microscopy. We reveal that both the holotype and the new specimen are ac...
One of the aims of micropaleontological studies is to unravel the geological history of the surface of the earth in a manner that can be achieved as reliably, in relatively quick time and at the same time be economically be reasonable. Oil companies, who invest hugely in this high risk business of oil exploration, have undoubtedly gained much from micropaleontological studies. This is because o...
Fossils of the sponge Angulosuspongia sinensis from calcareous mudstones of the middle and upper part of the Kaili Formation (Cambrian Stage 5) in the Jianhe area of Guizhou province, South China, exhibit an apparently reticulate pattern, characteristic of the Vauxiidae. Energy Dispersive X-Ray Spectrometry (EDS) and Raman spectroscopy analysis indicate the presence of silica in the skeletal el...
Phosphatic sedimentary rocks preserve a record of early animal life different from and complementary to that provided by Ediacaran fossils in terminal Proterozoic sandstones and shales. Phosphorites of the Doushantuo Formation, South China, contain eggs, egg cases, and stereoblastulae that document animals of unspecified phylogenetic position; small fossils containing putative spicules may spec...
We describe new carnivoran fossils from Kalodirr and Moruorot, two late Early Miocene sites in the Lothidok Formation of West Turkana, Kenya. The fossils include a new species of viverrid, Kichechia savagei sp. nov., a new genus and species of felid, Katifelis nightingalei gen. et sp. nov., and an unidentified musteloid. We also report new records of the amphicyonid Cynelos macrodon. These new ...
Both the fossil record and molecular data support a long evolutionary history for the Araceae. Although the family is diverse in tropical America today, most araceous fossils, however, have been recorded from middle and high latitudes. Here, we report fossil leaves of Araceae from the middle-late Paleocene of northern Colombia, and review fossil araceous pollen grains from the same interval. Tw...
5 Thalassinoides sp. 19 INTRODUCTION 6 Genus Trichichnus Frey, n. gen. 20 Purpose and scope 6 Trichichnus linearis Frey, n. sp. 20 Stratigraphy 6 Genus Zoophycos Massalongo, 1855 22 Correlation of Fort Hays exposures 9 Zoophycos sp. A 22 Petrology 9 Zoophycos sp. B 22 Paleontology 9 Miscellaneous burrows 23 Acknowledgments 10 Arthrophycus-like burrows 23 TRACE FOSSILS (ICHNOLOGY) 10 Scaphopod-s...
Abelisauroid predators have been recorded almost exclusively from South America, India and Madagascar, a distribution thought to document persistent land connections exclusive of Africa. Here, we report fossils from three stratigraphic levels in the Cretaceous of Niger that provide definitive evidence that abelisauroid dinosaurs and their immediate antecedents were also present on Africa. The f...
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