Human and ape phylogeny

[Ken Kinman]

Hi John,
     Of course, one should always question whether a cladistic analysis has
been correctly rooted.  But I am far more concerned about the rooting of
phylogenies of bacteria, molluscs, and other groups (including the
arthropods, which I will be "harping on" in the near future).
     Using gibbons to root the great apes doesn't cause me much concern, and
the assumption that they are basal hominoids is not really controversial (at
least compared to the orangutan controversy).  However, I would agree with
you that a cladistic analysis using Old World monkeys to root hominoids
(using these same characters) might be instructive.  However, I strongly
suspect that the phylogeny would be basically the same (but who knows?).
              ------ Cheers,
                          Ken
***************************************
>From: John Grehan <jgrehan at SCIENCEBUFF.ORG>
>Reply-To: John Grehan <jgrehan at SCIENCEBUFF.ORG>
>To: TAXACOM at USOBI.ORG
>Subject: Human and ape phylogeny
>Date: Fri, 4 Apr 2003 09:55:40 -0500
>
>Here's a question for all the cladistic experts on this list. I admit to
>having a relatively superficial expertise with cladistics so I want to
>measure my current perceptions against any responses on this list. My
>question concerns the 'cladistic' quality of an article cited on this list
>as increasing the support for a human-chimp/african ape clade vs human
>orangutan by S. Gibbs, M. Collard, and B. Wood (2002) Soft-tissue anatomy
>of the extant hominids: a review and phylogenetic analysis. Journal of
>Anatomy 200: 3-49.
>
>At first glance the paper seemed very impressive. The authors utilized 171
>characters and a cladistic analysis. The number of taxa was limited to
>humans and extant apes only which did make me wonder if some of their
>characters might not qualify as synapomorphies with further comparison
>including at least the old world monkeys. Then I read that "No a priori
>judgements were made as to the primitive or derived condition of
>characters". My reading of that statement is that the characters were not
>'cladistic' in the sense of each standing as proposed synapomorphies.
>Instead they were phenetic.
>
>The authors then state that "Hylobates was assumed to be the basal hominoid
>genus and the cladograms were rooted accordingly". Since the characters
>were not defined as synapomorphies with respect to an outgroup, making one
>of the taxa the basal lineage seems to be an externally imposed criterion
>rather than being generated from the characters themselves. With this root
>the characters were subject to 'cladistic' analysis.
>
>Am I correct to view this paper as a 'cladistic' analysis of phenetic
>characters with an arbitrary rooting of one of the taxa being analyzed. If
>I am then this paper hardly seems to me to stand up as a reliable support
>for the human-chimp clade. I am getting old and perhaps my understanding of
>cladistics based on what I read by Hennig, Nelson where cladistics was all
>about the analysis of proposed synaomorphies is now out of date and I
>missed the boat where cladistics is now all about the analysis of phenetic
>characters.
>
>John
>
>Dr. John Grehan
>Director of Science and Collections
>Buffalo Museum of Science
>1020 Humboldt Parkway
>Buffalo, New York 14211-1293
>Voice 716-896-5200 x372
>Fax 716-897-6723
>jgrehan at sciencebuff.org


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