Re: Ye Olde Duckbill Dinosaur

[Stanley Friesen <sarima@ix.netcom.com>]

At 08:38 AM 8/8/97 -0400, Tomporowski, Steve wrote:
> I was very familiar with the then current 
>restoration of the duckbill dinosaur 'Trachodon [spelling?]' as 
>having a wide duck-like bill and swimming in water.  Now that I've 
>gotten back to dinosaurs I know that that restoration is changed, in 
>fact even that diorama at the Peabody has been removed.  I assume 
>Trachodon is an invalid name now. 

Well, sort of.  The name _Trachodon_ was first given to a hadrosaur
*tooth*.  It turns out that hadrosaur teeth are not generally diagnostic,
so the animal so named is unidentifiable. Thus the name _Trachodon_ is
technically a Nomen Dubium - a "doubtful name". Also, it turns out that the
original tooth is probably from a *crested* hadrosaur, perhaps similar to
_Corythosaurus_, rather than from a flat-headed hadrosaur as seen in the
reconstruction you mention.

> Since I've missed the changes due to new information, what happened 
>to Trachodon and his wide flat bill?

This reconstruction is almost certainly based - loosely - on the form which
until recently was called _Anatosaurus copei_, but is now named _Anatotitan
copei_.  This form does indeed have a flatter, wider beak than other
hadrosaurs (thought probably not as duck-like as in the early
reconstructions).

The recent change in name is in part due to the fact that the other, more
"ordinary" species of _Antosaurus_ have been moved to _Edmontosaurus_.
When this was done it was realized that _A. copei_ simply did not fit in
with the other species in form, so it was eventually given its own genus,
as it should have been to begin with.

[Note, this means that the genus _Anatosaurus_ is no longer really valid].

--------------
May the peace of God be with you.         sarima@ix.netcom.com
                                          sfriesen@netlock.com