Tuesday, September 25, 2012

Nimbacinus dicksoni

Until now, life has moved at such a violent pace that I have not been able to return to this blog until now. I am nearly 26 and my life is completely different to the circumstances I was living in back in 2009. It feels like another world. In April 2008, my Mother died and my immediate family entirely fragmented. Since that point, until quite recently, I was very much alone in my struggles. At the end of 2009, I gradated with a Bachelor of Science with majors in geology and zoology from the University of Tasmania. I then relocated to Sydney to complete my Honour's year in vertebrate palaeontology, which will be the subject of this post. The course is only supposed to take a year, but due to untold dramas including assault and homelessness and the general incompetance of people and the system, I emerged, at the end of 2011, in triumph with a grade of 2nd Class 1st Division and this reconstruction of Nimbacinus dicksoni:
Nimbacinus was a 15 million year old thylacinid, which are a group of carnivorous marsupials that resembled canids because they evolved to follow similar lifestyles, not because they were closely related. They only became extinct fairly recently, in 1936, when the last Tasmanian tiger died in a zoo in Hobart, Tasmania. (I used to drive passed the remains of this zoo every time I went to university in Tasmania.) The Tasmanian tiger, (Thylacinus cynocephalus) was the largest Australian marsupial carnivore and was approximately the size of a German Shepard dog. It was called a tiger because of the dark stripes it bore on its hindquarters. Here is a photo of the late Tasmanian tiger:
The title of my thesis is Postcranial morphology of Nimbacinus dicksoni (Thylacinidae: Marsupialia) and a discussion of the functional morphology of the limbs. That may seem like a daunting mouth full but all it means is that I described all the bones of this animal except for the skull, which was already described by Steve Wroe and Anne Musser in 2001, and I discussed how it may have used its limbs when it was alive. I also did a head reconstruction of Nimbacinus based on figure 3 of Steve Wroe and Anne Musser's cranial description.
A large part of the requirements of the work was that I produce stippled drawings of all the bones of Nimbacinus and of the Tasmanian tiger and described them anatomically in the text. Here is the ventral vew of the pelvis of the Tasmanian tiger:
Overall, I had to produce nearly 60 of these such images, each bone was illustrated in anywhere from three to five different angles to demonstrate their significant features. I did an average of three drawings a day for nearly six months. I concluded that Nimbacinus was not just a miniture Tasmanian tiger. The former was about the size of a fox. Proportionately, Nimbacinus had stronger forelimbs, so whatever it did in terms of hunting, it was consuming different prey than the Tasmanian tiger and possibly doing a lot of grappling with it. The Tasmanian tiger, on the other hand, was more of a pursuit predator that chased small wallabies.

1 comment:

Mark said...

Dear Reswob,

I hope you are still active and get this. I am a research professor in human genetics in Canada. I am doing a study of certain skeletal structures in eutherian versus metatherian mammals. Specifically, I am looking at the occurrence of the ossified (bony) patella (kneecap). Most marsupials lack a bony kneecap, but I have not been able to find out anything about the thylacines or nimacines. It sounds like your thesis on the skeleton of Nimbacinus would be relevant, but I can't find it online nor the specific university and department where you were. Can you assist? Thanks, Mark E. Samuels, Associate Professor in Medicine, University of Montreal