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Re: Theropod herbivory - parallel evolution or one clade?



Tim Williams wrote: "If _Incisivosaurus_ is a herbivore, as interpreted by Xu et al. (2002), then herbivory/omnivory may be primitive for the Oviraptoriformes. Given the suggestion that troodontids may have been omnivorous, this dietary preference may be primitive for a much wider group, like Maniraptora. Maybe the immediate ancestors of birds were omnivores, and began climbing trees in order to nibble on leaves? Many evolutionary scenarios have focused on the possible role of predation in the evolution of avian flight, but a possible role for herbivory has received far less attention, AFAIK."

Only derived troodontids have teeth with large dentical that are suggestive of ominory; basal troodontids have smaller serration and in some cases more recurved teeth. Given dromaeosaurs and predaceous basal troodontids, it seem unlikely to me that herbivory is primitive to paraves...but stranger things have happened.


Scott Hartman Science Director Wyoming Dinosaur Center 110 Carter Ranch Rd. Thermopolis, WY 82443 (800) 455-3466 ext. 230 Cell: (307) 921-8333

www.skeletaldrawing.com

-----Original Message-----
From: twilliams_alpha@hotmail.com
To: dinosaur@usc.edu
Sent: Thu, 16 Nov 2006 6:06 PM
Subject: Re: Theropod herbivory - parallel evolution or one clade?

David Marjanovic wrote:Â
Â
That's an understatement. Since its description everyone seems to
agree >*Incisivosaurus* is the basalmost known oviraptorosaur. The oviraptorosaurs >and the segnosaurs seem to be each other's closest relatives, so there is a >relation.Â
Â
Sereno erected the name Oviraptoriformes for the therizinosaur-oviraptorosaur clade. _Incisivosaurus_ and _Protarchaeopteryx_ (if they are not one and the same) are both regarded as basal oviraptorosaurs. _Shanyangosaurus_ may belong here too, or as a basal oviraptoriform.Â
Â
If _Incisivosaurus_ is a herbivore, as interpreted by Xu et al. (2002), then herbivory/omnivory may be primitive for the Oviraptoriformes. Given the suggestion that troodontids may have been omnivorous, this dietary preference may be primitive for a much wider group, like Maniraptora. Maybe the immediate ancestors of birds were omnivores, and began climbing trees in order to nibble on leaves? Many evolutionary scenarios have focused on the possible role of predation in the evolution of avian flight, but a possible role for herbivory has received far less attention, AFAIK.Â
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CheersÂ
Â
TimÂ
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