Re: Sereno's Prosauropoda

[Dinogeorge@aol.com]

In a message dated 7/7/99 4:16:42 PM EST, TWILLIAMS@canr1.cag.uconn.edu 
writes:

<< Does this mean the Melanorosauridae could be the basal prosauropod family? 
 
 Sereno regards the Prosauropoda as monophyletic i.e. the sister-group to the 
 Sauropoda, and not a paraphyletic series of outgroups.  This could mean that 
 the melanorosaurids are closest to the origin of the sauropods after all - 
 not as the most "advanced" prosauropod group, but as the most "primitive" 
 prosauropod group. >>

I generally regard melanorosaurids as basal sauropods rather than 
prosauropods and have asserted that prosauropods are derived relative to 
sauropods, not sauropod ancestors (not a idea new with me by any means). 
Primitively, sauropods retain five-toed hind feet complete with at least 
two-phalanx digit V (as in Shunosaurus), whereas prosauropods have usually 
lost digit V and typically show it as only a splint metatarsal, the obvious 
derived state relative to the five-digit sauropod hind foot. There are other 
features of certain prosauropods that are derived relative to sauropods; see 
my article on sauropod phylogeny in Gakken's Dino-Frontline #2.