> Glenn Morton wrote:
>
> One of the things that the modern face illustrates is the nature of the
> fossil record. The earliest man with a modern human face is now about a
> million years old. Then there is a gap of 250-300,000 years before the
> second example if found. After that is another gap of about 600,000 years
> before the third example. Such gaps are found in the fossil record for the
> earliest examples of any item you wish to name, from wine to farming to
> sewing needles to pottery to faces to fossil animals. While the earliest
> example is often quoted as the oldest, with any item, it is highly unlikely
> that the first example was actually fossilized or preserved.
>
> Another thing about the fossil record which must be treated with care is
> the danger of exrapolating from a single example. Just as there are people
> alive today whose features might be mistaken for Neandertal (or some
> descendant thereof), is it possible that the skull from Gran Dolina is also
> an exception. With a half million years intervening til the next find,
> that guy might just have been a funny looking h. erectus?
>
>
James,
One of the interesting things that Glenn does not refer to is that a
simple change in the development of the sphenoid retains the juvenile
trait in this key bone of the skull. We as Homo sapiens have the juvenile
form, Homo erectus and Neanderthals do not as a group. (see
article in Nature 1998, volume 393, page 158-162. Or the news article at
http://www.pathfinder.com/living/latest/RB/1998may/r/821.html.
Interestingly, the retention of the juvenile trait of the sphenoid may aid
vocal communication as it also will give a more sapiens appearance to the
erectus and even Australipithicus skull.
I believe that in terms of paleontological species, a population of
hominids that consistently differ on such a trait from the norm may be
appropriately classified as a seperate species. (Something I know Glenn will object to.
;-) )
John