Comments on: Human Evolution’s Cookie Monster, Oreopithecus

By: Jean-Francois Morf

Jean-Francois Morf — Thu, 29 Dec 2011 19:44:32 +0000

Disparition définitive de Homo Floresiensis 16’000 an AV JC, mais pourquoi donc?
Après 100’000 ans de refroidissement climatique, la majorité du carbone terrestre est à cette époque au fond des océans, sous forme d’hydrate de méthane, et de méthane saturant l’eau des océans. La convection du magma terrestre devient par hasard un peu plus forte: elle aspire donc les continents vers le bas et elle fait remonter le fond des océans autour du rift. Tout à coup, le rift s’ouvre sur toute sa longueur, le magma sort massivement, se répand sur le fond des océans, et vaporise l’hydrate de méthane. Un fort courant ascendant se forme au dessus du rift, et tous les océans se mettent à mousser du méthane, comme le champagne mousse du CO2. Ce qui fait monter le niveau de la mer de plusieurs Km. Arrivées en haut, les bulles de méthane flambent, vaporisant l’eau de mer. D’énormes nuages se forment sur toute la terre, provoquant des pluies diluviennes. Homo Floresiensis disparaît, noyé, mais Homo Sapiens survit. Allez maintenant sur Google Maps, en vision satellite, et introduisez, par copier-coller, les coordonnées suivantes: 39°26′ 26.26″N 44°14’5.3″E , et cliquez. Ensuite, cliquez 5 fois de suite sur +. Vous ne voyez pas ce que c’est? Cliquez sur “photos”, et cliquez sur toutes les photos! Surprise! 16 mille ans AV JC…

By: Marcel F. Williams

Marcel F. Williams — Wed, 28 Dec 2011 17:51:28 +0000

The latest evidence shows that the latest oreopithecines lived at the same time as the earliest African hominin, Sahelanthopus (6.7 to 7.1 million years ago) at a time when there was a land bridge connection between North Africa and Italy. It should also be noted that Sahelanthropus and Oreopithecus are extremely similar in their cranio-dental morphology.

Oreopithecus has 15 cranio-dental similarities with Sahelanthroups; Australopithecus has 14; Homo, 10; Pan and Gorilla, 5; Pongo, 4; and Hylobates; 3.

By: Erin Wayman

Erin Wayman — Mon, 12 Dec 2011 22:17:30 +0000

Jeff, you raise some interesting points. I agree that it’s probably best not to talk with too much certainty when it comes to human evolution. Every new find can rewrite what we thought we knew. In terms of Oreopithecus, if the fossils really are in such a poor state, it’s probably difficult to draw any definitive conclusions.

In terms of bipedalism being present in the last common ancestor of chimps and humans, I think it’s unlikely. Here’s why. Orangutans split from the African apes about 15 million years ago, then gorillas split from chimps+humans about 10 million years ago, and finally chimps and humans split some 7 million years ago. We know that orangutans and gorillas are not bipedal. If the last common ancestor of chimps and humans were bipedal, that means chimpanzees underwent an evolutionary reversal, when a species loses a recently evolved trait and goes back to the more primitive condition. In other words, it sort of “reverted” back to the non-bipedal form of gorillas and orangutans. Scientists think evolutionary reversals are rare in evolution. It is more parsimonious, as they say, to assume bipedalism only evolved in our lineage.

By: Jeff Michals-Brown

Jeff Michals-Brown — Sat, 10 Dec 2011 02:40:59 +0000

Two thoughts.
First: Every time we find an older, well-preserved hominin it seems to push back the origin of bipedal locomotion in primates. When I was young, it was presumed to be an adaptation that went hand-in-hand (chuckle) with tool use. Ardipithecus’ almost-upright locomotion was the latest big surprise. I wonder if Oreopithecus could possibly bear on the question? Is it possible that it evolved not in hominins but our common ancestor with chimpanzee line, but then been lost from that line?

Second: I find paleoanthropologists to be much too prone to excessive certainty. They might almost be partisan politicians, if they stuck to only two interpretations of the evidence. Why can’t they just do as researchers in other sciences are wont to do, and say of their favorite interpretation, “it’s one reasonable hypothesis,” or even “we don’t know yet”?