Human-orangutan phylogeny

[Ken Kinman]

John,
     Just to clarify what was discussed yesterday, I do not believe
mutations in developmental genes to be a widespread problem for
morphological analyses.  So I am definitely not arguing for molecular over
morphological.  Only if it can be shown a small molecular change in a
development gene may have cause a majority of the morphological changes
being discussed.  I saw a pattern in the orangutan-human data, which still
makes me suspicious.  I have not yet seen a similar pattern in the
human-African ape data.
     Anyway, I heard from Gary Schwartz about the thick enamel supposedly
shared by humans and orangutans, and they develop it by two different
development pathways, so it is almost certainly a convergent character.  As
for the "long hair" character, I strongly suspect it should be thrown out as
a synapomorphy as well.
         ------ Gotta run,
                     Ken
****************************************
>From: John Grehan <jgrehan at SCIENCEBUFF.ORG>
>Reply-To: John Grehan <jgrehan at SCIENCEBUFF.ORG>
>To: TAXACOM at USOBI.ORG
>Subject: Human-orangutan phylogeny
>Date: Thu, 10 Apr 2003 12:25:40 -0400
>
>Some TAXACOM respondents earlier comments on the plethora of morphological
>'evidence' for the human-chimp clade in terms of number of characters or
>number of papers. I am continuing to examine such papers and I am beginning
>to wonder whether the numbers will really add up to anything.
>
>Right now I am reading through a paper by Collar dand Wood (2000) How
>reliable are human phylogenetic hypotheses? (PNAS 97: 5003-5006). This
>might be cited as another paper providing additional support of the
>human-chimp connection, but the majority of characters are extracted from
>Shoshani et al who extract many if not most of theres from Groves (1986 and
>modified 1995). So one gets a layering of character sources, apparently
>without any direct individual observation of said characters.
>
>Further Collard and Wood extract out only 96 craniodental characters for
>Gorilla, Homo, Hylobates, Pan, Pongo and an outgroup (Colobus). This seems
>to result in some strange characters. For example their character 8 is
>presented as autapomorphic for Pongo so its totally uninformative!  Same
>for character 24! (which in Shoshani et al is also recorded in several
>monkeys so its effectively a plesiomorphic character and probably should
>not have been included at all). There are other autapomorphies (which are
>probably plesiomorphies in Shoshani et al) as well.
>
>They even include characters that are declared to be in the out group. For
>example, character 26 is in Gorilla and the outgroup! Perhaps I have missed
>something about cladistic characters, but my understanding was that a
>character present in the outgroup suggests it is a plesiomorphy within the
>group analyzed.
>
>Character 28 has two states - not developed (0) and developed (1). My
>understanding of a binary state synapomorphy is for (1) to represent the
>derived state (which is how the distribution goes most of the time in this
>paper, but for 28 their distribution is as follows:
>
>Homo 0, Pan 1, Gorilla 1, Pongo 1, Hylobates 0, Colobus 1.
>
>But the most interesting part of this paper was the tallies for particular
>clades. There were 11 for Human/chimp/gorilla, 5 for human/chimp, and 10
>(!!!) for human/orang (despite not taking all the potential human-orang
>synapomorphies.
>
>So on the face of it, 35 characters have been proposed for human-orangs
>(for which so far I have not seen any clear-cut refutation of any)
>outnumbers the five proposed by Collard and Wood for chimps, and even far
>outnumbers their human-chimp-gorilla clade.
>
>Collard and wood prejudice their analysis by stating (p. 5004) to support
>the hypothesis that craniodental characters are reliable for reconstructing
>the phylogenetic relationships of fossil primate species and genera, the
>resulting cladogram matched the molecular cladogram, or a partially
>resolved cladogram comprised only molecular clades or the strict consensus
>comprised only clades compatible with the molecular cladogram. So here it
>is clear that the authors do not view morphology as independent evidence of
>phylogeny!
>
>Their parsimony analysis of two quantitative data sets resulted in Homo
>being the sister taxon of Gorilla-Pan-Pongo (although I found only three
>characters giving this direct support. There are a lot of mutistate
>characters and quite a few are confusion in their polarity (eg absent or
>not known in outgroup, derived state in Hylobates).
>
>Their parsimony analysis of a qualitative matrix resulted in a Homo-Pongo
>in one clade (based on straight numbers for their data this is of no
>surprise) and a Pan-Gorilla clade.
>
>Of course nether of these hypotheses are 'supported' because they do not
>agree with the TRUE molecular tree.
>
>I could add more, but unless I am missing something fundamental (and I may
>have made some mistakes in what is admittedly a quick reading) it seems
>that this paper is problematic, not only for its choices and assertion of
>putative synapomorphies, but also for its prejudice in favor of molecular
>trees as the truth and arbiter of phylogeny
>
>Since there were some very strong orangutan critics posting on TAXACOM I am
>sure they will be able to demonstrate how Collard and Wood actually do have
>a robust morphological character set, and also demonstrate that any
>morphological character not in harmony with phenetic molecular characters
>should be discarded - and while we are at it throw out all systematists
>working on morphology since genetics is at the truth of the matter anyway
>(has anyone yet made this sort of proposal to NSF (or other funding
>organizations in other countries) to eliminate funding for morphological
>systematics?).
>
>John Grehan
>
>
>
>
>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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