Re: Australopithicus factual info

Alex Duncan (
25 Jun 1995 18:40:46 GMT

In article <> Stephen
Younge, writes:
>Subject: Australopithicus factual info
>From: Stephen Younge,
>Date: Sat, 24 Jun 1995 23:00:30 GMT
>>Okay, anyone who is interested -
>Are the following capsules of information factually correct?
>Think of it as a test of things you learned long ago!
>Australpithicus afarensis
>. 5 mya - 3 mya
>. the earliest Australophiticus
>. walked erect
>. 310-485 cc brain, "ape-like" organization
>. 3.5 to 5 feet tall, very stocky
>. lived in trees and on the ground
>. no tools yet
>* NOTE: bipedalism came long before human-like brain!
>Australpithicus africanus
>. 2.8 mya - 1.8 mya
>. 428-510 cc brain, roughly the size of a chimp's
>. brain expanding but still "ape-like"
>. built like A afarensis
>. maturation period still as short as apes (3 years)
>. represents either an evolution towards homo, or
> an evolutionary dead-end

No, not all of this info. is correct, though it is close.

Beginning w/ A. afarensis

The earliest known A. afarensis is from Fejej, in Ethiopia near Omo. It
is dated to ~3.9 Myr.

Whether or not A. afarensis is the earliest australopithecine will depend
on whether or not White et al. can convince us that A. ramidus merits a
generic distinction, as well as on whether new material from the lake
Turkana region dating to older than 4.0 Myr will be placed in
Australopithecus or not.

No tools THAT WE KNOW OF YET. The fact that both humans and chimps use
tools suggests that this trait would have been present in our common
ancestor, and thus in all human ancestors. The fact that we find no
definite tools associated w/ A. afarensis may simply mean that they
didn't make tools that the fossil record preserves.

A. africanus

~3.2 Myr (Makapansgat) - 2.38 Myr (Sterkfontein) -- the dating of Taung
is still controversial, though most folks now seem to agree on around 2.5

I doubt any A. africanus had a brain as big as 510 cc (you're not
thinking of ER 1813 are you?). The biggest I know of is around 480 cc.

As far as we can tell from scrappy fossils, the postcranial skeleton is
identical to A. afarensis.

May represent an ancestor of Homo, of A. robustus, or of both; or -- may
have gone extinct w/ no descendants.

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