Re: Ye Olde Duckbill Dinosaur

[Dinogeorge@aol.com]

In a message dated 97-08-08 07:43:10 EDT, Steve.Tomporowski@us.ms.philips.com
writes:

<< When I was a kid sneaking down to downtown New Haven to visit the Peabody 
 Museum (which was free then....) 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.

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

In a message dated 97-08-08 13:46:03 EDT, garrison@efn.org (Garrison
Hilliard) writes:

<< Trachadon took a wrong turn at Anatosaurus... >>

In a message dated 97-08-08 13:47:21 EDT, MWEDEL@gslan.offsys.ou.edu
(Dictator-for-life Calvin) writes:

<< Here's the story as I understand it.  I'm sure there will be gaps and 
 gaffes, but that's what all these other gifted people are here for.
 
 When I was a kid (in the 80's) the story I got through various 
 channels was that Trachodon was a junior synonym for Anatosaurus, 
 and that it wasn't an aquatic animal.  The tail couldn't have been 
 much good for swimming because a network of ossified tendons held it 
 rigid, the tooth batteries could have chewed a lot more than just 
 aquatic vegetation, and the old duck-bill has been given a good set 
 of cheeks, so the mouth doesn't reach very far up the side of the 
 head.  Oh, yeah, and the webbed front foot is gone, replaced by a 
 meaty mitt formed from the three middle fingers.  I think that some 
 conifer material might have been recovered from a hadrosaur torso, 
 which would indicate a coniferous diet for at least one of the 
 beasts, but that might just be my fevered imagination.
 
 Just about the time I got used to Anatosaurus, it too got deep-sixed 
 (I don't know when all this was published, but I didn't learn about 
 it until fairly recently.  That could just be me.).
 As I understand it, Anatosaurus is now a junior synonym of 
 Edmontosaurus, and a really humongous former Anatosaurus is now 
 Anatotitan.
 
 Mebbe we could hit up Mike Brett-Surman to give us the poop. >>

In a message dated 97-08-08 14:53:04 EDT, brstahl@sprynet.com (Bryan R.
Stahl) writes:

<< Looking in the DINOSAURIA, all Trachodon species seem to be Nomina dubia. 
 Some species to Edmontosaur and some to Anatosaur. >>

Here's the story: Around 1855-1856, Joseph Leidy was handed some fossil
dinosaur teeth and other fragmentary remains that Ferdinand Vandiveer Hayden
had picked up while prospecting in the Judith River valley in Montana (then
part of the Nebraska Territory). These he described as a number of different
dinosaur genera, one of which was _Trachodon_. (Others included _Troodon_,
_Deinodon_, _Palaeoscincus_,  and _Thespesius_.) Leidy placed two teeth in
the species _Trachodon mirabilis_.

The identity of _Trachodon_ remained a mystery until the discovery of good
remains of _Hadrosaurus_ in New Jersey, which Leidy described two years
later, in 1858. Teeth associated with the _Hadrosaurus_ skeleton were similar
to those of _Trachodon_, and paleontologists entertained the idea that these
two genera might be the same. Note that they still didn't have a good skull,
so they didn't know about the duckbill; basically they considered
_Hadrosaurus_ and _Trachodon_ to be advanced relatives of the European
_Iguanodon_.

Numerous teeth similar to those of _Trachodon_ and _Hadrosaurus_ continued to
be discovered in the American and Canadian West for many decades, and these
two genera acquired numerous species. Other hadrosaur tooth genera were
proposed as well, such as _Cionodon_ and _Diclonius_. Paleontologists had a
field day referring any of the species in any of these genera to any of the
other genera. The lack of decent skeletal remains made for much confusion.

Finally the first good skull showing a duckbill and skeleton were unearthed
and were described by Cope as _Diclonius mirabilis_ in 1883. He used Leidy's
original species name, _Trachodon mirabilis_, but gave it his own generic
name, _Diclonius_, which he had coined earlier for other hadrosaur teeth from
the Judith River area. He considered _Trachodon_ to be an invalid generic
name that needed to be replaced. Actually, Cope was correct in considering
_Trachodon_ to be doubtful, but his name _Diclonius_ is equally doubtful, and
it was certainly unwarranted to suppress Leidy's genus in this fashion. But
that's Cope for you.

The nomenclatural problems raised by the overusage of _Trachodon_ and other
dubious hadrosaur tooth genera were, at the beginning of the 1900s, so
tangled that when it came time to mount Cope's "Diclonius mirabilis" skeleton
at the American Museum of Natural History, the staff left it unlabelled,
calling it a "trachodont" skeleton. By then the genus _Trachodon_ had been
used as the basis for the whole duckbilled-dinosaur family, Trachodontidae;
hence the musuem label.

It was another few decades until Richard Swann Lull and Nelda Wright
published their monograph on North American hadrosaurs in 1942. There they
reviewed all the previous species, decided the tooth genera and species were
mainly junk, and coined the fresh name _Anatosaurus_ for the commonest North
American flat-headed (uncrested) duckbilled dinosaur. The type species of
_Anatosaurus_ was _Anatosaurus annectens_, based on a nice partial skeleton
with skull that Cope's rival Marsh had originally described, using his >own<
hadrosaurian genus, as _Claosaurus annectens_ in 1892. Cope's "Diclonius
mirabilis" skeleton became the type specimen of a different Lull & Wright
species, _Anatosaurus copei_.

This is how matters stood for many years, until the pace of discovery of new
hadrosaur skulls and skeletons made it apparent to Mike Brett-Surman (and
unindicted co-conspirator Jack Horner) that _Anatosaurus annectens_ was just
too similar to another hadrosaur species, _Edmontosaurus regalis_, to remain
in a separate genus. Since _Edmontosaurus_ had been created by Lawrence Lambe
in 1917, it had priority over Lull & Wright's _Anatosaurus_, and Brett-Surman
sank _Anatosaurus_ as a junior synonym in 1979 or thereabouts (actually,
first in his unpublished M.Sc. thesis in 1975). He kept the species separate
from the type species of _Edmontosaurus_, as _Edmontosaurus annectens_.
(Actually, since I was already corresponding with Mike at the time, I'm the
first to have published the combination _Edmontosaurus annectens_, in
_Mesozoic Meanderings_ #1, 1978, but I did it with his blessing and with
reference to his dissertation.)

But _Anatosaurus copei_ was a different story: it was too different from
_Anatosaurus_ (=_Edmontosaurus_) to remain in that genus. So a new genus was
coined for that species (also in Brett-Surman's thesis, but not published
until 1990, in an appendix to an article on hadrosaur morphometrics by Ralph
Chapman and Brett-Surman). The species became _Anatotitan copei_. The name
_Anatotitan_ was originally suggested by Donald Baird, then Jack Horner's
mentor, and Mike Brett-Surman used it.

When it came time to revamp the American Museum's dinosaur displays earlier
in this decade, the mount of Cope's skeleton (one of two at the museum,
incidentally, positioned side by side in the Cretaceous hall) was finally
relabelled from "trachodont dinosaur" to _Anatotitan copei_, which it is my
guess it will stay for quite some time.

As for Leidy's original _Trachodon_ teeth, modern analysis suggests that one
is hadrosaurian and the other ceratopian; the hadrosaurian tooth is presently
considered the type specimen, so _Trachodon_ remains a hadrosaur. But Jack
Horner has analyzed a multitude of duckbilled-dinosaur teeth during his
career, and he (along with Lull & Wright) thinks the type tooth may belong
not to a flat-headed hadrosaur but to a crested one--a lambeosaurid, possibly
_Corythosaurus_. Horner also sees similarities with _Prosaurolophus_ (an
uncrested hadrosaurid) teeth. Unfortunately, there is no way to identify
which genus of lambeosaurid this might be, so _Trachodon_ will remain a
doubtful lambeosaurid (or maybe hadrosaurid) genus into the foreseeable
future.