Preparation continues on the fossil bones collected during the 2017 field season at the Eric the Red West site, near Cape Otway, south-west of Melbourne. Apart from the associated blocks of rock that contain 11 bones from three different taxa, a number of isolated dinosaur teeth and a mystery tooth, which is yet to be identified, have been prepared.
As mentioned in the May 2017 update, a theropod caudal (tail) vertebra was discovered, which came from a dinosaur about the size of Australovenator wintonensis – a medium sized carnivorous dinosaur measuring approximately six metres in length, found near Winton in Queensland. This was not the only bone from a theropod dinosaur to be discovered this year. A cervical (neck) rib was also recovered which measured approximately 12 cm in length. Cervical ribs are much smaller than the ribs in the body of a dinosaur, so this rib must have come from a big animal, larger than A. wintonensis. Comparison with other large theropod dinosaur cervical ribs showed a similarity with Allosaurus fragilis, a northern hemisphere Jurassic dinosaur, measuring 8 – 12 metres in length. Although Allosaurus lived in the northern hemisphere long before the dinosaurs from Eric the Red West were walking around, there have been a number of theropod dinosaur bones from both the Otway and Strzelecki Groups that have been described as “Allosauroid” – similar to Allosaurus. There are very few dinosaur cervical ribs in the Vertebrate Palaeontology Collection in Museum Victoria and none of them is as large as the one found this year.
On Saturday 14th October Dinosaur Dreamers Nick van Klaveren, John Wilkins, Nova Taylor, Mike Cleeland and local resident Mike Cunningham took part in a one day dig at the Flat Rocks site, near The Caves, Inverloch. This site was the focus of 20 annual field seasons from 1994 – 2013 and had produced thousands of fossil bones and teeth. Nick is a field geologist and had mapped the Flat Rocks site many times over the years. Perusing his old maps recently he noticed an area that had not been sampled, which he realised could be the edge of the fossil layer. So he persuaded a few other Dinosaur Dreamers to help him sample the layer. Over a few short hours the five diggers removed enough rock to fill a dozen or more buckets, which were then carried up the steps to The Caves car park before being transported to the shed of Dinosaur Dreaming coordinator Lesley Kool, in Wonthaggi.
A few weeks later a larger group of “fossil tragics” got together at Lesley’s home and we spent the weekend breaking up the rock that Nick et al had carefully collected. As the rock came from the edge of the fossil layer we expected to find only small bones that had been carried by the river and deposited on the edge of the channel. Our guess turned out to be correct with the largest bone, a thin platy bone, measuring about six cm in length. The rest of the bones were between one and two cm in length, some incomplete and scrappy. Approximately 30 bones were discovered in the rock, most of which were not scientifically important. However, we did find a small ornithopod tooth, an ornithopod claw, a partial theropod tooth and a small jaw, just over one cm long, containing a single tooth.
On initial examination of the jaw I thought that it was a juvenile ornithopod lower jaw, with a small tooth exposed. However, on checking the jaw under the microscope and removing a small amount of matrix from around the tooth I quickly realised that what I thought was a single rooted dinosaur tooth was in fact a double rooted mammal tooth, which means that we had a mammal jaw. As our mammal expert, Dr. Tom Rich is currently overseas and won't be returning until early December, we must all wait patiently for his return to find out what type of mammal jaw we have. Is it another tribosphenic mammal like Ausktribosphenos nyktos or a monotreme like Teinolophos trusleri or something new? Only time and Tom will tell.
Hopefully Tom will be able to tell us something by the Dinosaur Dreaming Annual Report Day on Saturday 16th December, to be held at 1pm in Museum Victoria.
Images: all photographs by Lesley Kool
1. Theropod cervical (neck) rib 2. Happy crew of fossil tragics breaking rock in Wonthaggi 3. John and Doris looking for the other half of a bone 4. Fishy platy bone – the largest found from the collected rock
2. Happy crew of fossil tragics breaking rock in Wonthaggi
4. Fishy platy bone – the largest found from the collected rock
1. Theropod cervical rib
3. John and Doris looking for the other half of a bone