Big Al 2

Allosaur Invades Museum Lobby
Allosaurus “Big Al Two”
by Neal Immega, Master Docent
Finally, the museum has a cast skeleton of an Allosaurus on display. It has gastralia and a furcula! The new
beastie stands guard over the minerals gift shop and delights ten-year-olds over near the new entrance to the
Grand Hall. It stretches 26 feet from snout to tail and is 8 feet high at the hip. Even so, this specimen is much
smaller than other allosaurs and may be a new species. This specimen is fondly called “Big Al Two”.
Allosaurus, Big Al2, protecting the gift shop.
Where – In 1996, Al2 was found in the Howe quarry near Shell, Wyoming, one of the favorite dig sites of of
the dinosaur pioneer Barnum Brown. A Swiss museum, the Sauriermuseum Aathal, dug it up and had Black
Hills Institute (famous for finding the T. rex, Sue) prepare and mount it. You will need a passport to visit the
original bones in Switzerland.
History – This is the second allosaur found by the Swiss museum’s team. In 1991, they were digging in what
they thought was the private land when they found a wonderful skeleton of an Allosaurus that they called “Big
Al”. The only problem was that it really was on BLM land and they had to turn the dig over to the University of
Wyoming and the Museum of the Rockies. Big Al Two was found not far away.
Name – Allo translates as “strange” or “different”, and saurus to “lizard.”
Age – Morrison formation, Jurassic age, same as our Diplodocus. I tell visitors that I have a trick question for
them: “Could T. rex take Diplodocus in a fight?” Well, now you can ask them the same question about
Allosaurus. The first answer will still be the same: T. rex lived 100 million years later than Dipsy – Cretaceous
vs. Jurassic. As for Diplodocus vs. Allosaurus, I suspect that 20 tons of sauropod trumps a ton of carnivore.
Skull – The most obvious feature of Al2’s skull is that he has horns above his eyes. You know, I bet OSHA
would mandate such a design. Al2’s jaw is split just like T. rex’s so that he could swallow huge things, but his
teeth are much sharper and smaller than T. rex’s. This means that Al2 was an active predator and needed to kill
things by biting them. Check this out: can you tell if Al can see in front of him like T. rex? It looks like Al does
not have T. rex’s excellent binocular vision, which I thought was present in all predators. Surprising.
Cutting Teeth in the jaw.
Arms – Al2 has powerful arms and wicked-looking claws. Remember, the groove on each claw core was there
to provide a blood supply for growing nails. The actual claws would be at least 50% longer than the core. Al2
has a 3-fingered claw rather than the more evolved 2-finger claw of T. rex. (Remember Bakker’s “hand jive:
Pelvis – All the carnivorous dinosaurs in the hall have a T-shaped bone that sticks down between their legs.
This allows the muscles to be anchored to bone with an angle of 30 to 60 degrees. Contrast this with a human
where the leg muscles anchor to the pelvis at less than 10 degrees. This means at humans would be quicker but
these dinosaurs would have much more power. You might also want to contrast the downward orientation of the
pubic bone on this carnivore with the backward-oriented one on the hadrosaur star of “Dino Mummy CSI”.
Carnivorous Al2 didn’t need the big gut of herbivore Leonardo.
Furcula – Thanksgiving holidays are coming up, so I want you to pay particular attention to Al2’s wishbone.
Birds have a “furcula” (Latin for “little fork”). It sits at the base of the throat and apparently aids birds in
breathing during flight. We know that turkeys have wishbones but for the longest time we did not know that
carnivorous dinosaurs had wishbones. Now we do. The pigeons you chased as a child might have harbored
thoughts of former glory when their cousins ruled the earth.
View from the bottom showing the gastralia on the belly.
Gastralia – If you had though about this, you might have predicted that many animals with downward hanging
guts would have had something to keep them in place. In dinosaurs, these are frequently cartilage bands but
some have real bone that is braced with cartilage. These are the bones that look like floating ribs under Al2’s
stomach area.
Family – In Montana, Paleo Curator Dr.. Bakker has found what he has interpreted as a nursery area with prey
animals bones and lots of juvenile allosaur teeth. Maybe Allosaurus parents brought home hadrosaur haunches
to feed their chicks.
Damage – Al2 is in excellent shape for an adult with only a few broken and healed ribs.
References:
Furcula – Put wiki furcula into Google
Black Hills Institute cast - http://www.bhigr.com/store/product.php?productid=474
You can buy your own replica for $60,000.
Swiss Museum - Sauriermuseum Aathal, southeast of Zürich, Switzerland
-http://www.sauriermuseum.ch/english.htm