Changing Perceptions
In the Cretaceous Period, sauropods in North America were no longer the dominant group of herbivorous dinosaurs, with the duck-billed dinosaurs, such as Edmontosaurus becoming the most abundant. However, on other landmasses such as South America and Africa (which were island continents much like modern Australia) sauropods, in particular the titanosaurs continued to be the dominant herbivores. (See also: allopatric speciation.)
Saltasaurus was one such titanosaur sauropod, and lived around 70 million years ago. When it was first discovered, in 1980, it forced palaeontologists to reconsider some assumptions about sauropods as Saltasaurus possessed crocodile-like armour (osteoderms) 10 to 12 centimetres (4 to 5 in) in diameter. Previously, it had been assumed that size alone was sufficient defence for the massive sauropods. Since then, palaeontologists have investigated the possibility that other sauropods may also have had armour; for example, the Argentinian Laplatasaurus.
Read more about this topic: Saltasaurus
Famous quotes containing the words changing and/or perceptions:
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—Henry Brooks Adams (1838–1918)
“We can conceive a thinking being to have either many or few perceptions. Suppose the mind to be reduced even below the life of an oyster. Suppose it to have only one perception, as of thirst or hunger. Consider it in that situation. Do you conceive any thing but merely that perception? Have you any notion of self or substance? If not, the addition of other perceptions can never give you that notion.”
—David Hume (1711–1776)