[Taxacom] 53 million year rabbit foot

Jason Mate jfmate at hotmail.com
Sun Nov 20 03:38:07 CST 2011


Hiya Michael/John
If you have a fossil and you can only be certain that it belongs to a particular group (Lagomorpha) but nothing more (is it a rabbit, a hare, Bugs Bunny,...?) then you only have a date for Lagomorpha, for the conceptual type, e.g. the whole group. In this way you make the least possible number of assumptions as the fossil only represents a date (53my) on a bunch of characters (= Lagomorphisness).
Jason

Date: Sat, 19 Nov 2011 01:54:11 -0800
From: michael.heads at yahoo.com
Subject: Re: [Taxacom] 53 million year rabbit foot
To: jfmate at hotmail.com
CC: taxacom at mailman.nhm.ku.edu

Hi Jason, Why is it parsimonious to assume that a fossil member of a group, but with an unknown position within the group, is basal in that group? Michael Wellington, New Zealand.

My papers on biogeography are at: http://tiny.cc/RiUE0
Information on my new book, 'Molecular panbiogeography of the tropics', is at: http://www.ucpress.edu/book.php?isbn=9780520271968

       From: Jason Mate <jfmate at hotmail.com>
 To: Taxacom <taxacom at mailman.nhm.ku.edu> 
 Sent: Saturday, 19 November 2011 8:53 PM
 Subject: Re: [Taxacom] 53 million year rabbit foot
  

I think KenĀ“s point is that nodes on dated phylogenies come with an uncertainty range, and hopefully the authors of the dated phylogeny provided them. Saying 35my and 35my (-20my) are very different things, so it is hardly proof of a fatal flaw in the edifice on fossil calibrated molecular phylogenies. In any case, the more fossils the better the calibration. In regards to crown versus stem, I would point out that if the fossil looks like a rabbit but
 you are uncertain about its exact placement, you assign it to all the rabbits (basal). It is not necessarily the best solution but it is the most parsimonius.
Jason
                           
_______________________________________________

Taxacom Mailing List
Taxacom at mailman.nhm.ku.edu
http://mailman.nhm.ku.edu/mailman/listinfo/taxacom

The Taxacom archive going back to 1992 may be searched with either of these methods:

(1) by visiting http://taxacom.markmail.org

(2) a Google search specified as:  site:mailman.nhm.ku.edu/pipermail/taxacom  your search terms here


   
  		 	   		  


More information about the Taxacom mailing list