[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]
Re: documentarian seeks direction and advice
A few answers to some of the questions I worked on directly:
>Supposedly the CAT scans of Sue's skull showed a huge olfactory bulb. How
>can you look at a cavity of a 67 million year old skull and tell that one
>part of an animal now one has ever seen is its oldfactory bulb. Could you
>look at MY skull and say, "Wow, that guy smells great!"
Using a comparative approach. All nonavian reptiles have a pair of
depressions under the frontal bone, sometimes encompassing parts of the
lacrymal and prefrontal. In all living reptiles, the olfactory bulbs go
there. We infer that the same is true for extinct reptiles, including T.
rex. And in tyrannosaurids, they are very large, implying either that
smell was very important (the reason touted by the media) or that very
large theropods needed very large olfactory bulbs as a scaling factor.
And yes, we could identify the space for the olfactory bulbs in your skull
- though humans don't have very high olfactory acuity, and the bulbs tend
to be small.
>There were a couple of Sue's bones that they'd never found before in
>another T-Rex, so how do they know where they're supposed to go or that
>they belong to Sue at all? Or maybe Sue isn't really a T-Rex because
>she's got these new bones?
In some cases (e.g. the stapes), they were attached to other bones (the
skull, in the stapes' case). In others, the mode of preservation and size
are precisely what we would predict had it come from Sue - true for the
furcula, for example. Your point is a valid one, and sometimes we cannot
tell whether a given bone belongs to a particular individual; our
confidence that what we've mounted on Sue belongs to Sue is very high, but
can never be perfect.
>Or maybe Sue isn't really a T-Rex because she's got these new bones?
In all cases, these are bones we would have predicted to be present on
phylogenetic grounds. It would have been far, far more surprising to
discover that tyrannosaurids genuinely didn't have stapes, for example.
>Sue's stapes is supposedly the first T-Rex ear bone ever found. How do
>they know that's what it is then?
1. It was sticking out of the ear-hole (external otic recess).
2. It looks just like the stapes found for other large theropods.
>Maybe it's a leg-bone from something she ate...OK probably not,
Sticking out of the ear, and looking just like a stapes? "Probably not" is
Christopher A. Brochu
Department of Geology
Field Museum of Natural History
1400 S. Lake Shore Drive
Chicago, IL 60605