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Atractosteus Atrox
''Atractosteus atrox'' (from ''atrox'', Latin for 'savage'), the Green River atrox gar, is an Extinction, extinct species of gar from the Ypresian, Early Eocene of western North America. It is known from many well-preserved specimens found in the famous Fossil Butte National Monument, Fossil Butte deposits of the Green River Formation in Wyoming, US, in addition to a possible vertebra from the Bridger Formation. A close relative of the modern alligator gar (''A. spatula''), it is the largest fish known from the Green River deposits, with two specimens known to reach at least in length, making ''A. atrox'' the largest known prehistoric gar taxon. It is one of two ''Atractosteus'' species known from Fossil Butte alongside ''Atractosteus simplex, A. simplex'', from which it can be differed by the characteristic ornamentation on its skull bones, in addition to its larger size. There is still significant variation within this species, and it is thus possible that it may represent mult ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Eocene
In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by the Eocene Lutetian Age. The Ypresian is consistent with the Lower Eocene (Early Eocene). Events The Ypresian Age begins during the throes of the Paleocene–Eocene Thermal Maximum (PETM). The Fur Formation in Denmark, the Messel shales in Germany, the Oise amber of France and Cambay amber of India are of this age. The Eocene Okanagan Highlands are an uplands subtropical to temperate series of lakes from the Ypresian. The Ypresian is additionally marked by another warming event called the Early Eocene Climatic Optimum (EECO). The EECO is the longest sustained warming event in the Cenozoic record, lasting about 2–3 million years between 53 and 50 Ma. The interval is characterized by low oxygen-18 isotopes, high levels of atmospheric pCO2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
