Re: AMARGASAURUS SATTLERI

[Dinogeorge@aol.com]

In a message dated 9/3/00 1:06:17 AM EST, NJPharris@aol.com writes:

<< Dinogeorge@aol.com writes:
 
 << It's difficult (though not impossible) to avoid paraphyletic genera in 
 this 
  situation. If D. sattleri and A. cazaui are sister groups, then D. sattleri 
  could indeed be placed in the genus Amargasaurus. But then what happens to 
  the common ancestor of Dicraeosaurus and Amargasaurus? >>
 
 Let's worry about that when we dig it up and recognize it as such, OK? >>

Have to worry about it now, lest one or the other genus be rendered 
paraphyletic. If the common ancestor is Amargasaurus, then that genus becomes 
paraphyletic because it excludes its descendant genus Dicraeosaurus; if it's 
Dicraeosaurus, then it's paraphyletic because it excludes its descendant 
genus Amargasaurus. If it's a third genus, it's paraphyletic because it 
excludes both descendant genera Dicraeosaurus and Amargasaurus.