Sunday, May 17, 2020

Facts and Figures About Sivapithecus, the Primate Also Known as Ramapithecus

Sivapithecus occupies an important place on the prehistoric primate evolutionary flow chart: This slender, five-foot-long ape marked the time when early primates descended from the comforting shelter of trees and started to explore the wide-open grasslands. The late Miocene Sivapithecus possessed chimpanzee-like feet with flexible ankles, but otherwise it resembled an orangutan, to which it may have been directly ancestral. (Its also possible that the orangutan-like features of Sivapithecus arose via the process of convergent evolution, the tendency of animals in similar ecosystems to evolve similar features). Most important, from the perspective of paleontologists, were the shape of Sivapithecus teeth. This primates large canines and heavily enameled molars point to a diet of tough tubers and stems (such as would be found on the open plains) rather than tender fruits (such as would be found in trees). Sivapithecus is intimately associated with Ramapithecus, a now-downgraded genus of central Asian primate, discovered in the country of Nepal, that was once considered to be directly ancestral to modern humans. It turns out that the analysis of the original Ramapithecus fossils was flawed and that this primate was less human-like, and more orangutan-like, than had initially been thought, not to mention disturbingly similar to the earlier-named Sivapithecus. Today, most paleontologists believe that the fossils attributed to Ramapithecus actually represent the slightly smaller females of genus Sivapithecus (sexual differentiation not being an uncommon feature of ancestral apes and hominids), and that neither genus was a direct Homo sapiens ancestor. Species of Sivapithecus/Ramapithecus There are three named species of Sivapithecus, each dating to slightly different time frames. The type species, S. indicus, discovered in India in the late 19th century, lived from about 12 million to 10 million years ago; a second species. S. sivalensis, discovered in northern India and Pakistan in the early 1930s, lived from about nine to eight million years ago; and a third species, S. parvada, discovered on the Indian subcontinent in the 1970s, was significantly bigger than the other two and helped drive home the affinities of Sivapithecus with modern orangutans. You might be wondering, how did a hominid like Sivapithecus (or Ramapithecus) wind up in Asia, of all places, given that the human branch of the mammalian evolutionary tree originated in Africa? Well, these two facts are not inconsistent: it could be that the last common ancestor of Sivapithecus and Homo sapiens did in fact live in Africa, and its descendants migrated out of the continent during the middle Cenozoic Era. This has very little bearing on a lively debate now going on about whether hominids did, indeed, arise in Africa; unfortunately, this scientific dispute has been tainted by some well-founded accusations of racism (of course we didnt come from Africa, say some experts, since Africa is such a backward continent). Name: Sivapithecus (Greek for Siva ape); pronounced SEE-vah-pith-ECK-us Habitat: Woodlands of central Asia Historical Epoch: Middle-Late Miocene (12-7 million years ago) Size and Weight: About five feet long and 50-75 pounds Diet: Plants Distinguishing Characteristics: Chimpanzee-like feet; flexible wrists; large canines

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