From: swf@teradata.com (Stanley Friesen)
Newsgroups: talk.origins
Subject: Re: fossil, schmossil... what about the bug!?
Date: 13 Oct 92 01:17:48 GMT
Reply-To: swf@tdat.teradata.com (Stanley Friesen)
Organization: NCR Teradata Database Business Unit

In article <1992Oct9.175555.25454@news.nd.edu> scharle@lukasiewicz.cc.nd.edu (Scharle) writes:
|In article <Bvr21w.3Kw@access.digex.com>, huston@access.digex.com (Herb Huston) writes:
|    ...
|   I thought that these articles were interesting for these reasons: 
|
|      It confirms that chimps are closer to humans than they are to 
|                 gorillas, hence that the classification of "ape" 
|                 which includes both chimps and gorillas probably 
|                 ought also to include humans (so, you see, we are 
|                 descended from apes, because we are apes) ...
|      Dryopithecus branchoi may be the nearest common ancestor of 
|                 gorillas, chimpanzees and humans (there seems to 
|                 have been some concern to some people in t.o that 
|                 such fossils were lacking)

Sigh, I really do need to see this article (the one in Science News
was less informative).

I *still* have reservations about this.  The genus Dryopithecus is usually
restricted to thin-enameles apes, and all living great apes are either thick-
enameled, or derived from thick-enameled ancestors (on the basis of enamel
microstructure).

Since the later thick-enameled apes (genus Sivapithecus) are convincingly
shown to be the ancestors of orang-utans, this leaves a very few, rather
fragmentary fossils as potential common ancestors for humans and African
apes (or even all living great apes).  The early thick-enameled apes
are usually either placed in Kenyapithecus and Ouranopithcus, or are
lumped in with Sivapithecus.

So, unless what these people are calling Dryopithecus branchoi is actually
a specimen usually placed in Kenyapithecus, or some such place, I have grave
reservations about thier conclusions.

(Damn, I never have my primatology texts available when I read this group,
so I cannot check the species names of the early apes to see in 'branchoi'
is a typical Dryopithecus or not).

|     [points out a couple of mistakes in my posting]
||> >    D. R. Begun: Miocene Fossil Hominids and the Chimp-Human
||> >Clade, pp. 1929-33
||> 
||> Hominids or hominoids?  The former seems implausible.
|  ...
|   I did a bit of reading on this.  It seems that there are some
|people who maintain that apes and humans are in the same family,
|that is Hominidae, thus the term "hominid" would be appropriate.
|Others place apes in a separate family, Pongidae, and thus the
|appropriate name for including both apes and humans would be
|"hominoid".  Have I got that right?
|
Pretty close.  The strict application of cladistic taxonomic principles
would require that humans and great apes be placed in a single taxon,
which might then be divided between the African apes (including humans)
and the Asian apes (the orang-utan).

But, if one allows all types of monophyletic taxa (in the original sense
of the word), then the derivation of humans from ancestral great apes
does not necessarily require them to be in the same taxon at that level.

The traditional classification, that is still consistant with the data
(when one relaxes the cladistic requirement for holophyletic taxa - which
is the term Peter Ashlock invented for what cladists call monophyletic)
is as follows:
	Superfamily Hominoidea  (aka hominoids)
	    Family Proconsulidae (extinct ancestral apes)
	    Family Hylobatidae (gibbons)
	    Family Pongidae (great apes - living and fossil,
			     including Sivapithecus and Dryopithecus)
	    Family Hominidae (aka hominids: Homo, Australopithecus,
			      and Parapithecus).

Well, more or less - there is considerable disagreement about *details*.
-- 
sarima@teradata.com			(formerly tdatirv!sarima)
  or
Stanley.Friesen@ElSegundoCA.ncr.com