نتایج جستجو برای: lower triassic
تعداد نتایج: 695069 فیلتر نتایج به سال:
Crittenden Springs in northeastern Nevada yields M. gracilitatis Zone ammonoids renowned for the finely detailed, exquisite preservation of the test, which sometimes even displays relict color patterns. Evidence reveals most of the fossiliferous Lower Triassic beds in the Crittenden Springs area are overturned and this conclusion places the Meekoceras gracilitatis Zone portion of the section an...
The Alpine Haselgebirge Formation represents an Upper Permian to Lower Triassic evaporitic rift succession of the Northern Calcareous Alps (Eastern Alps). Although the rocksalt body deposits are highly tectonised, consisting mainly of protocataclasites and mylonites of halite and mudrock, the early diagenetic history can be established from non-tectonised mudrock bodies: Cm-sized euhedral halit...
New Mexico Museum of Natural History and Science (NMMNH) locality L-3845 in the Petrified Forest Formation of the Chinle Group (Rio Arriba County, NM) yields nonmarine fossil vertebrates, invertebrates, and plants of Revueltian (early-mid Norian, ~218-210 Ma) age. We describe a 48 mm long by 19 mm wide decapod specimen (NMMNH P-29041) that originated in one of several fining-upward depositional...
Stable carbon isotopic analyses of organic carbon (d13C) in individual paleosol profiles from Permian–Triassic sequences of Antarctica reveal systematic isotopic variations with profile depth. These variations are in many cases analogous to those in modern soils, which are functions of redox conditions, soil development, and degree and type of microbial decay. In modern soils, these isotopic de...
A new discovery of skeletons of Revueltosaurus callenderi from the Upper Triassic Chinle Formation of Petrified Forest National Park, Arizona clearly shows that Revueltosaurus is not an ornithischian dinosaur as previously supposed. Features such as the presence of a postfrontal, crocodile-normal ankle and paramedian osteoderms with anterior bars place R. callenderi within the Pseudosuchia, clo...
Gliding adaptations in thoracopterid flying fishes represent a remarkable case of convergent evolution of overwater gliding strategy with modern exocoetid flying fishes, but the evolutionary origin of this strategy was poorly known in the thoracopterids because of lack of transitional forms. Until recently, all thoracopterids, from the Late Triassic of Austria and Italy and the Middle Triassic ...
During the end-Permian mass extinction, marine ecosystems suffered a major drop in diversity, which was maintained throughout the Early Triassic until delayed recovery during the Middle Triassic. This depressed diversity in the Early Triassic correlates with multiple major perturbations to the global carbon cycle, interpreted as either intrinsic ecosystem or external palaeoenvironmental effects...
New discoveries in the lower Popo Agie Formation (lower carbonate unit) of central Wyoming necessitated a reevaluation USNM 494329 from same unit, only known hyperodapedontine rhynchosaur western North America. Well Gondwanan deposits, hyperodapedontines appear to be restricted Carnian age (Late Triassic), with exception Teyumbaita earliest Norian Triassic) Brazil. Initially assigned c.f. ‘Hype...
The 34-million-year (My) interval of the Late Triassic is marked by the formation of several large impact structures on Earth. Late Triassic impact events have been considered a factor in biotic extinction events in the Late Triassic (e.g., end-Triassic extinction event), but this scenario remains controversial because of a lack of stratigraphic records of ejecta deposits. Here, we report evide...
Early archosauromorph remains from the Permo-Triassic Buena Vista Formation of north-eastern Uruguay
The Permo-Triassic archosauromorph record is crucial to understand the impact of the Permo-Triassic mass extinction on the early evolution of the group and its subsequent dominance in Mesozoic terrestrial ecosystems. However, the Permo-Triassic archosauromorph record is still very poor in most continents and hampers the identification of global macroevolutionary patterns. Here we describe crani...
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