RE: Deep Scaly Project

[david peters <davidrpeters@earthlink.net>]

I can't tell you how much I agree with your thoughts here, Tom.

Re: the number of characters, I was wondering if you, or anyone else, had any 
thoughts concerning Chippendale and Wiens 1994 (Systematic Biology 432: 
278-287) theoretical work that seemed to indicate that only 150 or so 
characters were needed to bring the probability of estimating correct phylogeny 
to the 95th percentile (rapidly evolving characters), while 300 skirts the 99th.

Thank you,

David




-----Original Message-----
From: "Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>
Sent: May 16, 2005 1:03 PM
To: david peters <davidrpeters@earthlink.net>, dinosaur@usc.edu
Subject: RE: Deep Scaly Project

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> david peters
>
> The Field Museum is part of a project to figure out the family tree of the 
> Diapsida.
>
> http://www.fieldmuseum.org/deepscaly/
>
> I was wondering, to date who has authored the most comprehensive account of 
> this
> clade? And why does it have to be improved or further resolved?
>
Note that this is for Squamata only, and by no means all of Diapsida!!

And why does it have to be improved? Because there remains major contraversies 
within it (esp., but not exclusively, the position of
snakes), and because previous work tends to be less global and thus more likely 
to miss important potential groupings (i.e.,
snake-only papers, or ones with just one examplar for each "family", or the 
like). Indeed, looking at their taxon sampling, it might
be nicer to see a lot more. After all, there are more living squmate species as 
there are living mammal species!!

Furthermore, this project will combine molecular and morphological data.

To do all of Diapsida to some reasonable scale would require many times the 
number of characters and taxa here. Even to do a "all
major types of fossil diapsids, minus the modern-type lepidosaurs and 
modern-type archosaurs" would be quite an task: literally
dozens to a few hundred of taxa and many hundreds of characters.

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
        Mailing Address:
                Building 237, Room 1117
                College Park, MD  20742

http://www.geol.umd.edu/~tholtz/
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796