Darren Tanke’s Gorgosaurus preparation 4: a maxilla

This update is for November 1-2. Great progress was made during these past two days on the Gorgosaurus skull. Much of the well-preserved snout and lower jaw were uncovered. Usually for a significant find such as this, I will do some background research on what I am going to prepare. I am after things like anatomical descriptions, illustrations and photographs of skulls and bones, and measurements. These assist one during the preparation phase. In some cases we will actually go to our Collections Department and sign out prepared bones for reference. I did this because of an odd deflected boney projection that suggested part of a suture on the upper jaw (maxilla) was broken and folded up. I compared the deflected piece to the same region of a prepared maxilla and they do look the same, but I am not sure this is the case (a broken and deflected piece of bone suture) and we might be looking instead at part of one of the palatal bones that became dislodged as the carcass rotted. Time will tell.

I recently began using a medium-sized airscribe on the specimen. This is useful for chipping pieces of rock away from the skull. The airscribe has a vibrating or rapidly stroking hardened steel tip which can chip through the rock or be moved rapidly back and forth as it is pushed forward (or pulled) against the rock. This latter action “shaves” the rock away. The amount of compressed air running through the tool adjusts its speed. The angle at which the tip contacts the rock can be adjusted manually as well as the amount of hand pressure used. Many variables for the tool’s use are thus created. One can even grind and shape the airscribe’s tip and these can be changed as required. Airscribes are a valuable tool for a preparator but can be very destructive in inexperienced hands.

The past two days of preparation have seen many of the upper jaw teeth exposed as well as the lower jaw. The snout is fully uncovered now and the work on the facial region begins tomorrow. This will be a bit slower work due to more complex anatomy in this area. There is a healing injury affecting the left surangular that is suggestive of a healing bite injury- not uncommon in Albertan tyrannosaurids. The pencil points to it and I include a close up of the wound showing the reactive bone which indicates the wound was still healing at time of death.

More to come soon! All photos here and in the series are owned by Darren Tanke and the Royal Tyrrell Museum.