Re: An alternative to ST and AAT

Susan S. Chin (
Sun, 1 Dec 1996 03:38:47 GMT

Phillip Bigelow ( wrote:
: > How different from each other are these distinct
: > species?

JW: At the current rate, it seems that virtually every
: > fossil hominid will be classified as a separate species.
: > Are you calling for a re-examination of the rules of
: > classification here? I have often wondered about these
: > Paleontological species.

PB: There are so few really good hominid specimens available
: that what you say is true. The problem is that if we
: haven't yet discovered a particular lucy bone, and if
: such an element is found, later, all by itself, who knows whether
: that element is from A. afarensis, or from a new species?
: Taxonomically speaking, this discovery process is messy as
: hell.

I don't know how often isolated fossil elements are found in the field,
but assuming this happened, and the anatomy of this element was
previously unknown in afarensis, and all available evidence fits within
the range of variation known in other afarensis skeletal elements, then
there's no good scientific reason to call it a new species with no
distinguishing characteristics separating it from afarensis. It's the
classic lumpers vs splitters argument. But when in doubt, it's more
parsimonious to accommodate it within known fossil taxa until and unless
more elements are found which show clear diagnostic differences. Most
species taxa which hold up thru time are those named with a reasonably
diagnostic set of characters supporting its differentiation from known