Re: R: R: Late J Heterodontosaurs (was Re: Sereno's Prosauropoda)

[Dinogeorge@aol.com]

In a message dated 7/9/99 9:01:14 AM EST, amaris@tin.it writes:

<< However, apart from the caniniform teeth, there are other features present
 in Heterodontosauridae and Marginocephalia, for example a jugal boss, and a
 diastema between the premaxilla and maxilla. >>

Jugal boss/hypertrophy seems OK but diastema also occurs in Ornithopoda 
(e.g., Hypsilophodon--but often hard to define because of lowered premax 
profile and premax tooth loss in many taxa!) and is likely primitive feature. 
In heterodontosaurians and marginocephalians diastema is well defined because 
it serves as slot for dentary fang.This is the apomorphy.