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Re: Differences between *Vancleavea* and thalattosaurs



While Wiens (2001) is probably the most widely used and likely the
best method for discretizing continuous characters, it is certainly
not the only way to accommodate them in a phylogenetic analysis.
Goloboff et al. (2006) suggest a method for keeping quantitative
continuous characters as they are in TNT.  I have not used this
feature yet so I can't speak intelligently on its utility, but TNT can
handle quantitative characters without manipulating them into
potentially arbitrary bins.

Goloboff, P. A., C. I. Mattoni, and A. S. Quinteros. 2006. Continuous
characters analyzed as such. Cladistics 22:1-13.


>
> There's nothing wrong with using proportional characters in principle, and I
> don't see why you call them "horribly prone to convergence", or what you
> mean by "tend to group into suites of characters". What I said is that it's
> not easy to deal with them, and I alluded to this paper which explains the
> best method so far, stepmatrix gap-weighting:
>
> John J. Wiens: Character analysis in morphological phylogenetics: problems
> and solutions, Systematic Biology 50(5), 689 -- 699 (September-October 2001)
>
> It's a bit time-consuming, but feasible; I used it in the 2008b paper with
> Michel Laurin.
>


-- 
Marc R. Spencer
PhD Candidate
121 Trowbridge Hall
Department of Geoscience
University of Iowa
Iowa City, Iowa USA 52242