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MY YEARLY SAUROPOD POST
Now that people have for some reason forgotten coelurosaurs.... It is time
for my ocassional dive into non-ornithischian subjects :-)
The trachea problem was dealt with to some degree by a certtain Dr Gale at SVP
97. He suggested that since the amount of tracheal dead space in sauropod
necks, they had to have some sort of "vent" lower down on the neck.
The night before the talk, I recall various attendees trying to understand
what he meant and various suggestions of symbiotic dromaeosaurs flew about...
It was nick-named 'the sauropod trachaeotomy talk.'
In the talk, he suggested that embryonic gill slits were retained as intake
vents and that the nares were just for smelling. There are many many many
problems with this scenario. Among these are the fact that the gill slits end
up in the jaw, ear, and shoulder, not along the neck, plus the fact that there
are pleurocoels and muscles in the way.
In my opinion his study was also flawed that instead of making a model of an
actual sauropod, but scaled up a varanid because "they were physiologically
more similar to big lizards than any other animals." Additionally, animals
like sperm whales and plesiosaurs have/had equally as long tracheae as most
sauropods and seem(ed) not to have any problem with dead space within the
trachea. Also, if sauropods indeed had bird-like lungs, then most of the
dead-space issue is averted.
I tend to think that the neutral neck positions that Parrish is finding for
sauropods is neat. What people should take in though, is that just because
sagging is neutral, it doesn't mean that they couldn't go up in the curved
positions that are so common in illustrations.
Also, the fairly straight, level necks of diplodocids tend to support the idea
that tthey reared up on their tails to feed, as the sag in the middle of the
neck as well as the head would become a blood-dump if they walked around on
all fours a lot.
NORTH AMERICAN EXTINCTIONS
Sauropods actually were around in North America for most of the Cretaceous,
only in the early Late Cretaceous was there a disappearance. Lucas and Hunt
wrote an important paper on Alamosaurus a few years ago.
The Statue of Liberty is kaput. Now that's disconserting.