Re: homo species

Alex Duncan (
7 Jul 1995 22:38:21 GMT

In article <3tftsa$> Howard Wiseman, writes:

>I have been heartened to see a recent increase in serious posts in this
>group discussing things other than the AAH. So I thought I'd throw out
>some topics I (a strict amateur)
>am interested in to try to get some more discussion.

I agree that this newsgroup should have more stuff in it than AAH, but I
just can't resist responding to it -- its so damn idiotic.

>It seems to me that the lumping/splitting pendulum has definitely swung
>back the other way (i.e. towards splitting) this past decade. Some people
>are now talking about many homo species (instead of just habilis,
>erectus, sapiens). These include (please correct me if I'm wrong because
>I'm writing from memory here)

Hopefully, as time passes, we get better at what we do. More realistic
examinations of inter- intraspecific variation are available today, and
the "splitting" reflects this.

>h. rudolfensis = KNMER1470 and related big-brained finds
>h. sp. = KNMER1813 (small brain but small teeth)
>h. habilis = original Olduvai finds (moderate brains)
>h. ergaster = KNMER3883, 3733, "turkana boy" etc.
>h. erectus = asian "erectus" only - java and china
>h. heidelbergensis = european and post-ergaster african "erectus"
>(Olduvai?, Broken Hill?), maybe later asian as well (Solo?, China?)
>h. neanderthalensis = european and west asian only
>h. sapiens = african from 120 kYA, then over the rest of the world

The latest take on the habilines is Bernard Wood's (Nature, 355: 783 -
790). He splits the habilines in H. rudolfensis & H. habilis. H.
rudolfensis would be the larger brained form, perhaps with a more modern
(i.e., human-like) postcranial skeleton. Paradoxically, also a more
australopithecine-like face. (Alan Walker says that when they were
excavating ER 1470, they initially thought it was an A. boisei.) H.
habilis is reserved for the Olduvai habilines, and the smaller brained
ones -- like ER 1813 -- from Turkana. Homo sp. is a term that has been
used for habilines that no one cares to identify to species. Most folks
seem to agree that ER 1813 and ER 1470 belong in different taxa, but they
are the most extreme individuals in terms of brain size and morphology.
The specimens that are intermediate between these two are problematic,
and I've seen little agreement over how they should be split up.
Homo ergaster has most recently been used for the earliest
African Homo erectus. I think only a minority of workers would agree
that these specimens should be separated from later African and Asian H.
erectus. The so-called "autapomorphies" of Asian H. erectus are not
unique, and are not present in all Asian individuals. Therefore, there
seems to be little basis for separating out ER 3733, etc. as members of a
different species.

>Any comments?
>What is the relation between these groups, and the
>australopithecus/paranthropus species?

Relationships between Homo species, and between Homo and Australopithecus
have not been resolved to anyone's satisfaction. Here's a consensus
view. Things that ALMOST everyone agrees on don't have question marks.

Homo sapiens
| Homo neanderthalensis
| |
| |
| |
| |
| |

?"Archaic Homo sapiens"
includes H. heidelbergensis
A. boisei A. robustus H. erectus
| | / \
| | ? ?
| | / \
| \ H. rudolfensis H. habilis
| ? / /
A. aethiopicus \ ? /
\ \ / \ /
\ A. africanus ------------?---
\ / |
\ / ?
A. afarensis---------------
A. ramidus

Hope you can decipher this.

>Should any (eg rudolfensis) not be homo?

I suppose the criterion for being in Homo is that one should be more
closely related to humans than to australopiths. Most character analyses
show habiline individuals clading up with modern humans before joining
the larger clade that includes australopiths. By this criterion, they
should be Homo, despite the retention of plesiomorphic features like
squared dental arcades, large flat faces, etc.

>Where does KNMER1805 fit in?

It wouldn't surprise me to find out this individual is pathological. It
has asymetrically placed sagittal crest and other oddities that don't
really seem to fit the habiline mold. However, its teeth are habiline,
and its cranial capacity (580 cm3 - I think) fit within the habiline
range of variation.

>What about the very early (c. 1.8 MYA) "erectus" from Georgia and java?

Some of the Javan stuff looks very primitive, even compared to the oldest
African erectus material. I haven't heard much about erecting a new
species for it though.

>Is this likely to be a conclusive list, or might other species be claimed?

We can always hope for more species. Some current splitting seems to go
overboard though (e.g. Fred Grine has resurrected "crassidens" for some
of the A. robustus material). I've also seen suggestions that A.
africanus, A. afarensis, and A. boisei could all be split.

>Is this list likely to be completely overturned as we discover more
>fossils? If so, should we give up naming fossil homonids indefinitely?

There is a purpose to naming hominid species. It reflects what we think
we know about hominid morphology and evolution. Taxonomic practice
changes constantly, but we should hope that it changes in response to
better and more information, rather than as part of a "trend". I suspect
we will see a new species of hominid (pre-Homo) based on new material
named within the next 2 years.

Alex Duncan
Dept. of Anthropology
University of Texas at Austin
Austin, TX 78712-1086