RE: Pelicosaurs: sprawling or not?

["Williams, Tim" <TiJaWi@agron.iastate.edu>]

Steve Brusatte wrote:

> Yes, Mike and David are correct here (AFAIK).  Monotremes do have
> somewhat of a sprawling gait, as likely did multis.  


I'm not contradicting you, and I know next to nothing about the finer points
of mammal evolution.  But is it possible that the sprawling gait of modern
monotremes is secondary and due to their specialized lifestyles.  The
echidnas (_Zaglossus_, _Tachyglossus_) are fossorial and the platypus
(_Ornithorhynchus_) is aquatic.  AFAIK, we don't have any postcrania from
extinct non-tachyglossid, non-ornithorhynchid monotremes to know what kind
of gait monotremes originally had.



Tim


------------------------------------------------------------ 

Timothy J. Williams 

USDA-ARS Researcher 
Agronomy Hall 
Iowa State University 
Ames IA 50014 

Phone: 515 294 9233 
Fax:   515 294 3163