[Taxacom] The real story (53 million year rabbit foot)

John Grehan jgrehan at sciencebuff.org
Sun Nov 20 10:29:38 CST 2011


 
-----Original Message-----
From: taxacom-bounces at mailman.nhm.ku.edu [mailto:taxacom-bounces at mailman.nhm.ku.edu] On Behalf Of Kenneth Kinman

> Lagomorpha (Leporidae splitting from Ochotonidae) originating at 50 million years ago.
>  The "rabbit" foot bones show that it was at least 3 million years earlier.  I could find
>  noone having suggested that crown group lagomorphs originating as late as 35 million
> years ago, and John jumped to a erroneous conclusion based on an erroneous news story.  

I'm ok that the news story misrepresented the molecular model. Not a problem.

>  So thank you John for having unwittingly brought forward this case where
> the molecularists did a darn good job. 

But their assertion "Lagomorpha (Leporidae splitting from Ochotonidae) originating at 50 million years ago" is still incorrect and the fossil provides nothing to that effect.

John Grehan


 
             ------------Ken                               
-----------------------------------------------------------
Michael Heads wrote:
Hi Ken, 
  
Why assume that the fossil is basal (stem-lagomorpha) just because it's a fossil? In fact, the authors concluded that the fossil wasn't stem group, and it indicates that 'diversification within crown Lagomorpha and possibly divergence of the family Leporidae were already underway in the Early Eocene'.   Michael Heads 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: Kenneth Kinman <kennethkinman at webtv.net>
To: taxacom at mailman.nhm.ku.edu
Sent: Saturday, 19 November 2011 4:38 PM
Subject: Re: [Taxacom] 53 million year rabbit foot 
 
Hi John,
      I think your conclusion that this contradicts molecular data

may be a bit exaggerated, and I'm not even sure the authors of the study were correctly quoted.
      In any case, whether the rabbits and hares diverged about 35

million years ago (although even you should be the first in line to question that date), the origin of crown Lagomorpha is no doubt older than that.  Anyway, the important question is whether these foot bones

are early crown Lagomorpha or older stem-Lagomorpha.  In the case of stem-Lagomorpha, your comments would be totally inappropriate, and even vis-a-vis early crown Lagomorpha, it's uncertain.      
      
       Not a case that I would point to as a grand failure of molecular dating (although even I might be somewhat suspicious of the 35-milion year figure).  On the other hand, you seem to jump onto it like it is a total failure of molecular dating.  I suggest that the dating MIGHT need some minor recalibration.  But in such cases, you seems prone to reactionary exaggeration. Calling this a "rabbit-foot" is

not particularly useful, especially if it is stem-Lagomorpha which predates the origins of rabbits.
            -----------Ken               
              
----------------------------------------------------------
John Grehan wrote: 
      Here's a recent example of an older fossil predating the molecular date. Note their comment that " previous fossil and molecular data suggested that rabbits and hares diverged about 35 million years ago". 
John Grehan
Good Luck Indeed: 53 Million-Year-Old Rabbit's Foot Bones Found One day last spring, fossil hunter and anatomy professor Kenneth Rose, Ph.D. was

displaying the bones of a jackrabbit's foot as part of a seminar at the Johns Hopkins University School of Medicine when something about the shape of the bones looked oddly familiar. That unanticipated eureka moment has led researchers at the school to the discovery of the oldest known record of rabbits. The fossil evidence in hand, found in west-central India, predates the oldest previously known rabbits by several million years and extends the record of the whole category of the animal on the Indian subcontinent by 35 million years. Published online in the February Proceedings of the Royal Society <http://royalsociety.org/> , the investigators say previous fossil and molecular data suggested that rabbits and hares diverged about 35 million years ago from pikas, a mousy looking member of the family Ochotonidae in the order of lagomorphs, which also includes all of the family Leporidae encompassing rabbits and hares. But the team led by Johns Hopkins's Rose found that their rabbit bones were very similar in characteristics to previously unreported Chinese rabbit fossils that date to the Middle Eocene epoch, about 48 million years ago. The Indian fossils, dating from about 53 million years ago, appear to show advanced

rabbit-like features, according to Rose. "What we have suggests that diversification among the Lagamorpha group-all modern day hares, rabbits

and pikas-may already have started by the Early Eocene," says Rose, professor in the Center for Functional Anatomy and Evolution 




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