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Re: Cretaceous Echinodon & Jeholosaurus

My impression was that Echinodon is now considered more derived than Agilisaurus, but not as derived as Heterodontosaurids.
In fact I was just wondering this morning if Jeholosaurus and Echinodon might be closely related.

From: "Tim Williams" <twilliams_alpha@hotmail.com>
Reply-To: twilliams_alpha@hotmail.com
To: Mickey_Mortimer11@msn.com, dinosaur@usc.edu
Subject: Cretaceous Echinodon (was Re: semilunate carpal)
Date: Mon, 13 Aug 2001 16:05:45 -0500

Mickey Mortimer wrote:

> I have a Late Jurassic (late Tithonian) age for the Middle Purbeck beds
> which yielded _Nuthetes_ (and _Echinodon_ as well).  Has this horizon
> re-dated?

I believe it has. [snip] There are many members
of the formation, the lowest of which (Caps Beds, Dirt Beds) may be
Tithonian. The others are Berriasian. Nuthetes destructor was found in
Cherty Freshwater Member, which is the sixth of fourteen members. Thus, it
was Berriasian.

Which means that _Echinodon_, also from the Cherty Freshwater Member, is
also Berriasian. If _Echinodon_ is included in the Heterodontosauridae
(e.g. Sereno, 1997), this would extend the temporal range of this group
forward by about 60-70 million years. (Not including the undescribed Fruita
"_Echinodon_" jaw from the Morrison.)



Timothy J. Williams

USDA-ARS Researcher
Agronomy Hall
Iowa State University
Ames IA 50014

Phone: 515 294 9233
Fax:   515 294 3163

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