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Re: Prolacertiformes and Protorosauria

David Peters wrote:

Once again, if sister taxa don't bear a family resemblance, you have to doubt the results.

Wait - I'm confused: don't the sister taxa bear "family resemblance" *by definition*? The tree constructs the best estimate of ancestry, using some kind of estimate of family resemblance. For morphological character sets, this usually means using a parsimony algorithm, with is optimizing the distribution of characters and using synapomorphies to define clades. Since you're joining taxa using shared derived character states, they *must* bear resemblance. The fact that those taxa may have some kind of qualitative or intuitive lack of "resemblance" doesn't mean you screwed up.

I added breaks at nodes that did either had closer excluded sisters or just plain did not make sense. Without an overall understanding of amniote relations, studies such as this one, undertaking such a huge gamut with too few real sisters will bear little real results.

How do you determine which groupings make sense - isn't that the point of constructing the tree in the first place? What's a "real sister"?



Michael Habib, M.S.
PhD. Candidate
Center for Functional Anatomy and Evolution
Johns Hopkins School of Medicine
1830 E. Monument Street
Baltimore, MD 21205
(443) 280-0181