Re: data

alex duncan (
5 Aug 1995 17:51:45 GMT

In article <3vr5m1$> HARRY R. ERWIN, writes:

>: maxillary sinus: absent
>--found in a source

What source? I was unaware that there were any Giganto maxillae
preserved. Please keep in mind that a lot of what's available out there
presents the ASSUMPTIONS of the authors. A lot of Andrews' work on
hominoid cladistics contains assumed character states. A rule I've
always tried to follow is that I don't use a character unless I have the
material to back it up with, e.g., Peter Andrews lists as a possible
synapomorphy of Pan & Homo "angle of ear bones over 90 degrees." I'm not
sure what "earbones" he's talking about, or how the angle was measured,
so I don't use the character. The state of phylogenetic analysis for
primates leaves a lot to be desired compared to what we see for other
groups. I suspect most vertebrate paleontolgists have a good old time
when they see what the anthropologists are up to.

>I've got a source for that one, since it wasn't defaulted. I'll look at
>home tonight. I suspect it was Oxnard, since I don't remember seeing it in
>Simons or Groves last night. In any case, it has no effect, since the rest
>of the apes in that little clade have the opposite polarity.

>: To get back to the case of Giganto, you're assuming that it has a lot of
>: character states that are similar to those seen in Pongo and Siva, even
>: though these parts aren't represented in the fossil record. I feel
>: confident that those assumptions are effecting the position of Giganto in
>: your cladogram.
>It didn't. Sorry.

You mention in another post that you think the characters that link
Giganto and Pongo are homoplastic. What characters (other than body
size) are you referring to?

(All of a sudden I realize that it must seem as if I have a violent
prejudice against Giganto being in a clade w/ Pongo. I really don't, I
just find the results surprising given that Siva has so many potential
synapomorphies w/ Pongo, and most of the characters that link Siva and
Pongo simply aren't known for Giganto.)

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