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Re: Fwd: A Clutter of Duckbills



 From: Dinogeorge@aol.com
 > But we'll never know unless you get your opinion in print AND can
 > provide better reasons than just your say-so.
 > 
How about his:


A. all published cladograms of these species place them in a single
monophyletic group.

B. The vast majority of the differences in these species are in the
crest, which is a intra-specific recognition structure.

C. Recognition structure tend to vary widely between closely related
species, and thus are of low taxonomic weight.  If recognition
structures are the main differences between two forms it is best to
place them in one genus.


Therefore it is best to unite these species in a single genus.


[By the way, in Diplodocus and Apatosaurus it is possible to identify
individual species by the dorsal vertebrae, so the mere fact that
the brachiosaur species are distinguishable this way is insufficient
reason to place them in separate genera].

swf@elsegundoca.attgis.com              sarima@netcom.com

The peace of God be with you.