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Re: Australopithicus factual info
Ralph L Holloway (rlh2@columbia.edu)
Tue, 27 Jun 1995 01:31:24 -0400
> Real data:
> Sts 5 cranial capacity = 485 cc
> Sts 71 cranial capacity = 428 cc
>
> Data is probably from Holloway, but I can check if anyone wants. The sex
> attribution of Sts 5 is open to question, and I've seen suggestions that
> this individual may be a male. The africanus sample is scrappy enough to
> make this a difficult case since Sts 5 has no canines (or any other
> teeth).
> It certainly is probable that an expanded sample size will yield
> endocranial volumes above 500 cc. The reason I suggested that 510 cc
> probably came from ER 1813 is because the cranial capacity of this
> individual is commonly cited as 510 cc. Also, numerous sources that are
> not up to date suggest that ER 1813 is an A. africanus (as did R. Leakey
> when it was discovered).
>
Yes, the data is from Holloway, and the 510cc for 1813 is also my
reconstruction. The attribution to A. africanus is difficult though. The
endocast is no help, given its morphology (see the journal HUMAN
NEUROBIOLOGY, 1983, for the descriptions of these endocasts, including
1470, and 1805). The teeth are unlike those of the S.African gracile
austalopithecines, being more Homo-like in their buccal-lingual reduction
relative to medial distal lengths. Some have regarded 1813 as the female
counterpart of 1470, but the endocast shape is very different, as well as
the size being far outside of normal sexual dimorphism, i.e., 752 for
1470 and 510 for 1813. Its possible, but I think unlikely given the
endocast shape. Then too, we really don't know what the dentition of
1470 was actually. Really puzzling is 1805, at 587 cc, with a morphology
more like a gorilla endocast than anything else.
As for the earlier declaration that the brain evolved last, or that
brain size increased before reorganization, it is all highly debatable.
Falk sez no, Holloway says yes. Need some independent assessment for
these endocasts. Falk has yet to answer my point regarding the A
afrensis AL 162-28 specimen, where the distance from the occipitsal pole
to the purported lunate sulcus is about 16 mm. On any chimp brain the
measurement is about 25-30mm, often with chimp brains of less volume
than 162-28. R. Holloway. >
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