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Megalodon Abbreviatus
Megalodon (''Otodus megalodon''), meaning "big tooth", is an extinct species of mackerel shark that lived approximately 23 to 3.6 million years ago (Mya), from the Early Miocene to the Pliocene epochs. It was formerly thought to be a member of the family Lamnidae and a close relative of the great white shark (''Carcharodon carcharias''). However, it is now classified into the extinct family Otodontidae, which diverged from the great white shark during the Early Cretaceous. While regarded as one of the largest and most powerful predators to have ever lived, the megalodon is only known from fragmentary remains, and its appearance and maximum size are uncertain. Scientists differ on whether it would have more closely resembled a stockier version of the great white shark, the whale shark (''Rhincodon typus''), the basking shark (''Cetorhinus maximus'') or the sand tiger shark (''Carcharias taurus''). The most recent estimate with the least error range suggests a maxi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquitanian (stage)
The Aquitanian is, in the ICS' geologic timescale, the oldest age or lowest stage in the Miocene. It spans the time between 23.03 ± 0.05 Ma and 20.43 ± 0.05 Ma (million years ago) during the Early Miocene. It is a dry, cooling period. The Aquitanian succeeds the Chattian (the youngest age of the Oligocene) and precedes the Burdigalian. The Aquitanian Age overlaps with the Harrisonian, Agenian, Pareora, Landon, Otaian, and Waitakian Ages from various regional timescales. Stratigraphic definition The Aquitanian Stage was named after the region Aquitaine in France and was introduced in scientific literature by Swiss stratigrapher Karl Mayer-Eymar in 1858. The base of the Aquitanian (also the base of the Miocene Series and the Neogene System) is defined as the place in the stratigraphic column at the first appearance of foram species ''Paragloborotalia kugleri'', the extinction of calcareous nanoplankton species ''Reticulofenestra bisecta'' (which forms the base of nanoplankton b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
