Darren Tanke’s Gorgosaurus preparation 1: getting started

Darren Tanke with Gorogsaurus life model

So it’s time to get started on the great Gorgosaurus preparation job. To get us started and introduce the work Darren Tanke has answered a few questions about the project:

How big is this thing?

It is not a particularly big animal. The ilium (hip bone) and skull length correlate and the ilium on this find was only 500 mm (about 20 inches) long so it is one of the smaller tyrannosaurid skeletons found in Dinosaur Provincial Park. The block itself is about 1.8 by 1.4 m and weighs about 500 kilos.

When and where did you find it?

As often is the case, the best specimen is found at the end of a field season. This one was found by me in the last 45 minutes of the last day of the 2008 field season. We wanted to spend out last 1/2 day in Dinosaur Provincial Park prospecting for fossils. I had been almost everywhere in the Park except for this one corner of badlands so we went there. The specimen was uncovered during part of the 2009 field season and airlifted out by helicopter early in 2010. (You can see a video of the airlift here).

How complete is it? Are all the bones there?

It was hard to tell at first how much was there, the exposed rock and bones therein were very crumbly and the bones falling to pieces. I found a small hand claw, gastralia (belly rib) fragments, and there was two bigger bones close together. The bigger of the two I thought was a tibia but it was only seen in cross-section so I was not certain. All the bones occurred over a short distance and all were small, indicating as small tyrannosaur was present. I envisioned it laying on its left side (which turned out to be correct, with the tail and neck in the hill. I was partially right on that account. There was part of the tail, but only several vertebrae. When we were uncovering the “tibia” we then realized it was the shaft of the pubis and further work revealed the articualted ilium- this confirmed which direction the skeleton lay. We explored ahead of the ilium looking for vertebrae and ribs. We did find some but they seemed somewhat jumbled up, as the animal rotted and water currents moved the skeleton around. We had about given up hope for a head when we found some neck vertebrae articulated and later on I found the snout of the skull just above the ilium, so the animal was curled up in the classic “death pose”, with the back strongly arched so the yop of the head rests on the top edge of the pelvis. We saw no evidence of hind limbs at all.

How long do you think the work will take?

The rock is quite soft, the rock/bone separation is good and the animal is small so things should go quickly- several months I’d say.

The unopenend Gorgosaurus jacket.

What is the basic plan here?

We will open the plaster field jacket from the bottom, so the skeleton you will eventually see will be upside-down from how it was buried. The plaster jacket will be peeled off by hand- I made sure it was thin as a helicopter would be lifting the jacket and we wanted to reduce weight. Then I will dig down through the rock with small hand tools such as knives, scrapers, dental pics, etc. Then when a bone is found it will be exposed halfway down its sides so the bone will be reliefed in the rock. I will work several areas of the block at once. This way glue can be drying on one bone while I expose others. We may take gthe bones out, or we may flip the whole jacket over and free the bones completely from the rock, but these are decisions that need to be made once the basic work of preparation is done first. It may just be reliefed in the rock as left at that. There are several other smaller bones that had washed away from the rest of the skeleton and these may be taken out of their jackets completely.

Are there any problems you can foresee, or any bits you are really looking forward to?

Having worked on the specimen in the field, I did not see anything that could cause us problems. The white sandstone rock was beautiful to work with. I am, of course, really looking forward to seeing the skull. This animal died young and this raises the question of “Why?” I’ll be curious to see if their are any injuries the animal suffered in its life (such as face-biting wounds) which are rather common in tyrannosaurids from Alberta, close to 50% occurrence. Also curious if there is a forelimb present.

What will happen with this when you have finished? Will it go on display, casts made or something else?

That is too early to say right now. Either of those options could occur, or not at all. It will be prepared for scientific study, but whom and when is unknown. We have several tyrannosaurid researchers visiting our museum annually so I am sure it will be worked into their studies or even our own staff could study it. If the skull is all there, and given its small size, it will be valuable for growth studies. In a sense it will likely be on public display during the work as we have video cameras in the lab that can be aimed at specific work projects and these are linked to television monitors in the public gallery. Also, it will be on public display via this blog and on the Royal Tyrrell Museum’s Facebook page– I will update an album there too as the specimen is prepared.