University of California, Merced

Matt Wedel

[![giant-cervicals-compared-500.jpg](https://svpow.files.wordpress.com/2008/03/giant-cervicals-compared-500.jpg)](http://svpow.files.wordpress.com/2008/03/giant-cervicals-compared.jpg "giant-cervicals-compared.jpg")

In a comment on the previous post, Amanda wrote:

*This might be a stupid question (I don't really believe that there are
no such things as stupid quetions) but do you find that sauropod
vertebrae are more highly pneumatic in larger sauropods?*

This is not only not a dumb question, it is one of most important
questions about pneumaticity in sauropods. The answer is complex, but
here at SV-POW! we embrace the complexity. So here's the dope:
brachiosaurids had the most highly pneumatic vertebrae of anything that
we've measured. Nobody's gotten a mamenchisaur vert into a CT scanner,
nor one from *Supersaurus*. I had a plan all worked out to do the
latter, but at the last minute we realized that the darn thing wouldn't
fit through the scanner. Occupational hazard. And not much scanning has
been done on titanosaurs, and none at all on the very big ones. So out
of the four clades that produced real monsters--mamenchisaurs,
diplodocids, brachiosaurs, and titanosaurs--we have hard data on the
monsters themselves from only one. Diplodocids and the more derived
titanosaurs did have pretty highly pneumatic vertebrae, but not all of
them were big. Some were downright dinky. And there were some pretty big
sauropods with only moderate pneumaticity, like *Jobaria* and
*Camarasaurus*. But they weren't the real monsters; neither of those
critters probably topped 1/3 of the mass of the biggest sauropods we
have fair remains for, let alone semi-apocryphal gigapods like
*Amphicoelias* and *Bruhathkayosaurus*. In short, the picture ain't
clean.

Draw a square and divide it into four smaller squares. Label one axis
with "Huge: Yes or No" and the other axis with "Highly pneumatic: Yes or
No", where "huge" means something in the 50+ ton range and highly
pneumatic means something with more than 60% air in its verts. All of
the boxes will be filled but one, which is the "Huge" and "Not highly
pneumatic" one. There are small sauropods that were highly pneumatic,
but so far no huge sauropods that weren't, at least based on the
evidence in hand.

It doesn't work out so well statistically, despite what I said in my
2006 SVP abstract. The problem is that the statistical significance
comes and goes depending on which taxa are included. That's a big
problem, because there aren't very many taxa for which we have enough
data to make doing the statistics worthwhile. And we have no crunchable
numbers on most of the biggest sauropods, including *Supersaurus* and
the biggest mamenchisaurs and titanosaurs, so even the lack of
statistical significance in some of the tests might be just an artifact
of undersampling the biggest and possibly most pneumatic taxa.

And there is a final caveat, which is that supposedly there is a 2.3
meter femur from the Early Jurassic of Morocco. Not much is known about
this. It was mentioned but apparently not figured in one short paper
published a while ago in French in a Moroccan journal that is
exceedingly hard to get a hold of. If it is really from the Early
Jurassic and it really is that big, that's pretty amazing. A 2.3 meter
femur is as big as that of the largest known brachiosaurids. It's up
there in *Argentinosaurus* country. But in the Early Jurassic it
presumably represents something pretty basal, which presumably means
something that is not highly pneumatic. You'll notice that there are a
lot of presumablys in there, but if that femur does represent a huge
basal sauropod, then we would have to go back to our boxes and put an X
in the last one, the "huge" and "not highly pneumatic" box. In which
case, forget about any statistical correlation between size and
pneumaticity. That giant eopod would be enough to wreck the correlation
all by itself.

And I just remembered *Turiasaurus*, which I should have thought of
sooner since I've seen the material (nyah nyah). The verts are a little
mooshed but not bad. I've scanned worse. And the folks in Spain would
like to scan it. My guess is that it will come about about like
*Camarasaurus*, in the \~60% zone. It is probably the biggest sauropod
with so little pneumaticity, except only the Moroccan monster, assuming
my guess is correct (FWIW, when Mike's tested me in the past my guesses
about air space proportion have been pretty darn close).

So what's the take home message? At least a few sauropods got rilly
rilly big without being rilly rilly pneumatic. And at least some rilly
rilly pneumatic sauropods were not particularly big. But the biggest
sauropods that we know of also seem to be the most pneumatic.

There is another interesting pattern, having to do with neck length and
internal complexity of the vertebrae, but I'm going to save that one for
another post.

The picture shows the three largest cervical vertebrae of anything,
ever, that anyone has found. Until somebody finds some more
[*Amphicoelias
fragillimus*](http://darrennaish.blogspot.com/2007/01/biggest-sauropod-ever-part-ii.html)
or *Bruhathkayosaurus*, this is as long as vertebrae are known to get.
*Sauroposeidon* and *Supersaurus* are my own photos; *Puertasaurus* is
after Novas et al. (2005:fig. 1). Each of those taxa--heck, each of
those vertebrae--is due its own post one of these days, but for now just
grok the immensity.

**Reference**

- [Novas, F.E., Salgado, L., Calvo, J., and Agnolin, F. 2005. Giant
  titanosaur (Dinosauria, Sauropoda) from the Late Cretaceous of
  Patagonia. Revisto del Museo Argentino de Ciencias Naturales, n.s.
  7:37-41.](http://www.macn.secyt.gov.ar/cont_Publicaciones/Rns-Vol07-1_37-41.pdf)


In a comment on the previous post, Amanda wrote:
<i>
 This might be a stupid question (I don’t really believe that there are no such things as stupid quetions) but do you find that sauropod vertebrae are more highly pneumatic in larger sauropods?
</i>
This is not only not a dumb question, it is one of most important questions about pneumaticity in sauropods. The answer is complex, but here at SV-POW! we embrace the complexity.

Rogue Scholar Beiträge

Were the biggest sauropods the most pneumatic?