[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).

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.

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