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Re: Hongshanosaurus houi, new psittacosaur



In a message dated 7/2/03 1:04:12 PM EST, twilliams_alpha@hotmail.com writes:

<< If _Echinodon_ is a heterodontosaurid, then this taxon extends the range 
of 
 this group into the Early Cretaceous. >>

Echinodon doesn't have the premaxillary tooth pattern shared by 
heterodontosaurs and later marginocephalians (the premax teeth are lost in most 
ceratopians 
but one or two are still there in Protoceratops and some Psittacosaurus 
species), so I'd place it in a sister group to the others.