And furthermore, if we are correct about the fact that the push to
bipedalism came as climate change transformed the landscape in eastern
and southern Africa ... squeezing some ape descendants into less and
less forested biomes, then those orthograde striders would tend to be
found in those regions that has undergone those environmental
transformations. The other apes seem to have retreated with the forest.
So, to the extent that early hominins were adapting to life in a less
heavily forested environment, one would expect to find their remains in
those places that were less heavily forested at the time.
It is interesting to note that some of the really early candidates for
hominin ancestors that are found earlier (closer to 6 mya) are both more
"chimpy" in their form and most likely to be associated with more
heavily forested environments than we typically see with, for example,
Australopithecus. They are also less clearly bipedal (remains are
awfully fragmentary and some of the inferences quite hopeful and likely
to be true under only the most fortuitous circumstances), even though
there are other hints in the remains that suggest that some of the
derived features associated with hominins are present.
So, it is a combination of the ancient distribution, taphonomy at death
and burial, and current conditions (including funding preferences) for
discovery and recovery.
So, in one sense we ARE finding most of the earliest hominin fossils in
east and south Africa because that is where we are looking. It is like
looking in the North American badlands for dinosaurs: you are bound to
find them. But there is also the fact that all the research and recovery
in these regions have indicated to us what kinds of ancient habitats
were attractive to these ancestors and where examples of those might be
found and be relatively accessible (as Bob pointed out).
On 11/10/2011 14:58, Bob Muckle wrote:
> Besides the probability of poorer preservation, also consider that
> there would likely be far less localities with sediments laid down
> millions of years ago in West Africa, now being exposed. Most of the
> well-known fossil localities in East Africa are within the Great Rift
> Valley, where erosion keep exposing fossils with relatively little
> effort. Another reason is that people tend to look where people have
> found fossils before, for the simple reason that there is a better
> probability of finding things. And what funding agency would want to
> provide funds for someone looking in West Africa when the chance of
> success is almost non-existent. The good news is that although
> researchers still tend to flock to the well-known localities of
> Ethiopia, Kenya, Tanzania and South Africa, in the last few decades
> some researchers have been able to get funding to look in others areas
> such as Chad, which has produced important discoveries. Also, there is
> likely to be increasing competi tion for funding from those
> researchers now looking for early humans (ie. pre- H. erectus) outside
> of Africa.
> >>> Nikki Ives <ikkinh@... <mailto:ikkinh%40yahoo.com>>
> 11/10/2011 12:05 PM >>>
> Hi All -
> A student in my physical anthropology class asked me this question and
> I'm not quite sure of the answer. Can anyone out there help me out?
> Student question: I was just curious to know why there aren't any
> documented fossil finds
> from West Africa. Unless I missed it in the textbook, it seems that
> majority of the African discoveries are from the North, East and South.
> Is there any theory or hypothesis surrounding this?
> [Non-text portions of this message have been removed]
Andrew J Petto, PhD
Department of Biological Sciences
University of Wisconsin -- Milwaukee
PO Box 413
Milwaukee WI 53201-0413
CapTel Line: 1-877-243-2823
Now Available!!! Scientists Confront Intelligent Design and Creationism.
[Non-text portions of this message have been removed]