Re: hominid species

[Tom Holtz <tholtz@geochange.er.usgs.gov>]

>most workers who specialize in hominid evolution do not recognize
>more than 3 species of Homo, namely H. sapiens, H. erectus, and H. habilis.
>Within H.s., however, most recognize three subspecies, H.s. neanderthalensis,
>H.s.sapiens (us), and an as yet unnamed groups collectively known as
>H. sapiens (archaic forms) - what was referred to H. heidelbergensis by
>a dinosaur listmember.  The currently accepted species of Australopithecus
>are: A. ramidans (only reported in fall, 95), A. afarensis (lucy et al),
>A. africanus, A. robustus (although some are now trying to put this back
>into Paranthropus, most would disagree), A. boisei (also sometimes called
>A. robustus boisei - what was once known as Zinjanthropus boisei).

It may be true that "most workers" agree with the taxonomy above, but
cladistics has finally reached the hominids.  More importantly, as people
work up from the other apes (and not down from the modern), it has become
clear that some of the previous synomymies are rather extreme lumpings
(e.g., the old story that a Neandertal in a suit and hat would be
indistinguishable from any New Yorker is 100% bull.  It might work in
Khazad-dum, but not in the modern world, not even New York City).  Looking
at these species using the tools we use to separate out other animal
species, it has become clear that it wasn't as simple as the 1970s and
1980s would have had it.  The following taxonomy is based primarily on the
contributions of B. Wood.

A. ramidus ('ramid' is "root" in Afar) lacks any derived character of
either Australopithecus, Paranthropus, or Homo, and is now in its own
genus, Ardipitheus.

Australopithecus retains the gracile species A. afarensis and A. africanus.

Paranthropus is the name for the robust speceies, P. robustus and P. bosei
(and maybe P. aethiopicus).  The Paranthropus line may have diverged before
the Australopithecus-Homo split, but some would have the robusts closer to
modern humans than are the graciles.

Homo now includes at least H. habilis, H. erectus, H. neanderthalensis, and
H. sapiens, and possibly a couple of other species (H. ergaster for the
African "erectus"; H. heidelbergensis for the early "Neandertal" types;
etc.)

>very few workers in hominid evolution would use the term "grade" to refer
>to branches along the homind tree or cladogram.  it is a term that human
>paleontologists abandonned when they abandonned the term "race".

Actually, the posting you included was almost certainly "gradistic", in
that "Australopithecus" includes all early hominids and excludes some
descendants of the ancestor of all "Australopithecus".

                                
Thomas R. Holtz, Jr.                                   
tholtz@geochange.er.usgs.gov
Vertebrate Paleontologist                           Phone:      703-648-5280
U.S. Geological Survey                                FAX:      703-648-5420
Branch of Paleontology & Stratigraphy
MS 970 National Center
Reston, VA  22092
U.S.A.