Finding fossils – the ichthyosaur from Boulia

Transcript

In August 2008 I set off on an expedition to Boulia, Queensland for the purpose of finding an ichthyosaur for display here at Museum Victoria.

Ihthyosaurs are a reptilian equivalent of a dolphin in the sense that they represent a marine form whose ancestors return to the sea and assumed a body form similar to a dolphin or a fish.

The reason that Boulia was chosen was that a 100 million years ago this was the site of a very shallow inland sea and numerous ichthyosaurs were known to have died and been buried there and so the hope was that we would find one. Boulia today is a flat desert, there’s very little vegetation and the wind scours it and deflates the surface so that bone is gradually being brought to the surface and so this make it an ideal place to look for this sort of thing.

We spent four days prospecting this area just basically walking around almost at random and we sighted six occurrences of bone which showed no sign of a skull. We excavated each one of these sites. The first two were complete duds, on the third one we got down about a metre and started to find the body of the animal and as we worked forward we got to the skull and the way the skull was oriented I thought ‘oh … we’ll we got the back of the head but not the snout’, which was kind of sad. But the operator of the backhoe said ‘Can I poke around a bit?’ And he very delicately dug around the front of the skull and he worked towards the end and got the very tip of the snout which was amazing because there’s almost none of these specimens known with the tip of the snout and this is it right here.

How did we get these fossils out of the ground once we realised we had something? Basically we used the same procedures that a doctor might use to set an arm, which is to basically encase it in plaster. We returned to Melbourne and we started the preparation process, which is very prolonged and eventually by sticking these fossils in acid we were able to remove the rock. Preparation of fossils typically like this would take more than a year and this one has taken a year to date to get it to this stage.

The teeth you’re seeing here are very typical of an animal that catches fish. And they are just perfect spikes for doing the job. What makes this specimen unusual is the fact that the snout is so complete. These various pieces go together and we have virtually the whole thing, which is not common among the fossils. To realise that you’ve seen something that nobody else has seen before and it has implications that no other fossil before it ever had, is a very exciting thing. It has only happened to me a few times but those are moments you never forget.

About this Video

Tom Rich, Museum Victoria, describes finding the ichthyosaur fossil and preparing it for display.
Length: 03:03
Photograph of a yellow plastic Tyranasaurus Rex