[sauropod@socrates.Berkeley.EDU: [Fwd: Re: [Fwd: Monster Apatosaurus]]]

[Mike Taylor <mike@indexdata.com>]

People,

There's been some interest in Apatosaurus cervical ribs on here
recently, so here (forwarded with permission, of course) is Matt
Wedel's commentary on his recent paper,

        Wedel MJ and Sanders RK. 2002. Osteological correlates
        of cervical musculature in Aves and Sauropoda
        (Dinosauria: Saurischia), with comments on the
        cervical ribs of Apatosaurus. PaleoBios 22(3):1-12.

Enjoy!

------- Start of forwarded message -------
Date: Thu, 10 Apr 2003 01:25:57 -0700
From: Matt Wedel <sauropod@socrates.Berkeley.EDU>
To: mike@indexdata.com
Subject: [Fwd: Re: [Fwd: Monster Apatosaurus]]

  Mike--

Here's the whole ugly story about how I went toe-to-toe with Apatosaurus 
and got my cerebellum handed to me.  And on top of everything you're 
about to read, I realized I made a couple of minor but galling errors in 
the paper that I'll have to correct with an erratum.  All in all, I'm 
feeling pretty equivocal about the whole shebang.  Well, the Apatosaurus 
shebang, anyway.  I'm actually feeling pretty good about the 
pneumaticity front.

Matt

Oh, yeah, I also promised you an explanation of the strange fate of the 
Apatosaurus paper.  Briefly, the following things happened:

1.  I thought, based on the absence of an anterior process on that big 
cervical rib, that the OU Apatosaurus was A. louisae.
2.  I felt that I couldn't really discuss cervical ribs without 
considering musculature, and I'd always intended on doing a 
poing-by-point comparison of muscle attachments in the cervical 
vertebrae of birds and sauropods.  So the original manuscript was 
entitled, "An unusually large cervical rib of Apatosaurus louisae from 
the Morrison Formation of Oklahoma, with comments on the cervical 
musculature of sauropod dinosaurs," or something similar.
3.  One of the reviewers pointed out that a vertebra referred to A. ajax 
also lacks anterior processes on its cervical ribs, and couldn't the 
Oklahoma form be a slightly-larger-than-normal A. ajax instead of a 
truly monstrous A. louisae?  In trying to answer that question, I 
realized that the anterior process of the cervical rib is also variably 
absent in A. excelsus, and that character alone was probably not going 
to be the key to figuring which species of Apatosaurus is represented at 
Kenton (in retrospect, this seems really obvious, but I was young and 
stupid then . . .).
4.  After more reading and thinking, I became very skeptical about the 
reality of Apatosaurus "species."  Several of the characters that 
Gilmore used to differentiate A. excelsus from A. louisae appear to be 
peculiar to CM 563, and are not present in the Field Museum skeleton 
described by Riggs in 1904.  Furthermore, after going through Gilmore's 
criteria, I think that the Oklahoma Apatosaurus has characters in common 
with both A. excelsus and A. louisae.
5.  Then I decided that I'd had the cervical rib backwards and if I 
reversed it, it matched one of the cervical ribs of A. ajax very nicely 
. . . A. ajax, which, according to McIntosh, is not clearly different 
from A. excelsus.
6.  At that point I didn't know what to think, other than that cervical 
rib morphology appears to be quite variable and not terribly informative 
in Apatosaurus.
7.  Then the editor got back to me to see if I was ever going to return 
the corrected manuscript. Ironically, all of the reviewers loved the 
muscle attachment portion of the paper, which I'd just tacked on to help 
people make sense of the first half of the paper.  So I decided to 
switch the order and emphasis of the two topics, and retitled the paper, 
"Osteological correlates of cervical musculature in
Aves and Sauropoda (Dinosauria: Saurischia), with comments on the 
cervical ribs of Apatosaurus," said comments basically being what I said 
above for point 6.

So, that's where I'm at now.  I think the Oklahoma Apatosaurus still 
needs attention.  In fact, I'm almost certain that some of the elements 
currently catalogued as Apatosaurus pertain to other genera, but I need 
to put more time in with the fossils to be sure, and that may not happen 
for a while.  I told Rich and those of his students that I've talked to 
that if anyone wants to work on that material, my part-time interest 
shouldn't get in their way at all.
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