Monday, June 20, 2011

Spinosaur distribution extended to Australia thanks to single cervical vert.

It’s official; we had representatives of the Spinosaurs, a group containing some of the largest carnivorous dinosaurs ever found, living in Australia in the Cretaceous. We know this from the basis of a single fossilised neck vertebra found near Cape Otway by Mike Cleeland and George Casper in 2005. This has been reported quite widely, having come to my attention in The Age of my home town of Melbourne and countless Twitter links. It seems that the currency of big meat-eating dinosaurs still holds strong. (See, it was the first thing I referred to in the opening of this post!) But what does this really mean? Well, from the perspective of a digger who works on the excavations from which the vertebrae was found, it is extremely edifying to have these sorts of things written down in an official capacity. It announces to the scientific community, and the world, an aspect of what was really happening in the Victorian Cretaceous. People that work on this material and our immediate entourage are aware of this stuff already – but pretty much no else is. So every paper like this adds a little more information to the great global picture of dinosaurs and allows researchers everywhere to incorporate our fossils into an overall understanding of Mesozoic life.

The excavations going on in Victoria are constantly turning things up but due to the nature of the rocks we dig in, we generally only find isolated bones, which can tell us a lot, but are not good for identifying species. Scientists will typically only name a species after a partial or complete skeleton or at best a jawbone or a tooth. Other parts of the skeleton are simply not unique enough to use to define a species. But even though we can’t identify or name species, we can often tell which families these animals came from.

We have identified a number of traditionally northern hemisphere theropod groups from Victorian sites such as Ornithomimids, Dromaeosaurids and recently a Tyrannosaurid. Slowly we are building up a picture of the Victorian Cretaceous dinosaur community and also getting an idea of how cosmopolitan most dinosaur families were. Expect to hear more announcements like this one in the future! We’ve got boxes and boxes of unexamined and unprepared fossils left to sort through.