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Re: Kaatedocus, new diplodocid sauropod from Jurassic Morrison Formation, Wyoming



Stephen Poropat <stephenfporopat@gmail.com> wrote:


> Regardless of whether or not it truly is a new genus and/or species,
> the specimen is beautiful, the photography is excellent, the
> measurements plentiful, and the descriptions clear.


Generally, I would agree.  Nevertheless IMHO it was a mistake to cite
_Kaatedocus_ as an example of Cope's Rule:

     "_K. siberi_ thus makes
      a nice example of Cope’s Rule as well, as a small sized,
      more basal taxon, compared with the large, advanced
      diplodocines _Barosaurus_ and _Diplodocus_"


First of all, it is drawing a long bow to corroborate Cope's Rule
based on only three taxa.  Recent comprehensive quantitative analyses
have failed to recover much (if any) support for Cope's "Rule",
including lineages within Dinosauria.


Second of all, it is difficult to justify Cope's Rule in view of the
more basal position of _Supersaurus_ relative to _Kaatedocus_ within
Diplodocoidea.






Cheers

Tim