Monday, June 29, 2009

Happiness is a bucket of lizards

One of the aspects of academic life in a small research institute is that you are sometimes called upon to supervise student projects that are outside your normal sphere of research activities. Broadening your experience and knowledge can only be a good thing so I welcome this. It also can provide an outlet of unusual activities that can break the monotony of the usual working week.
I am currently supervising one such project that is proving to be quite entertaining. The project is centred upon the almost entirely neglected herpetofauna that occurs alongside the famous Australopithecus fossils of the Cradle of Humankind World Heritage Area.
I found out, much to my surprise, when this project was started that there are no comparative osteological collections of southern african reptiles available in South Africa. So we have had to set about creating one. Fortunately we have been given permission to prepare the skulls of duplicate specimens from the Transvaal Museum collections. I was very pleasantly surprised at the breadth of the taxonomic scope we were supplied with - two specimens of over 40 species from the eastern half of
South Africa. So it was with some excitment that we took consignment of the above pictured and rather full bucket of lizards (Can anyone name the species visible? I'd be impressed if someone managed five or more).
Of course it is the students job to prepare the skulls, but with so many to get through, I've been mucking in and helping with the defleshing, which is surprising satisfying work, especially when you finish with a nice clean skull.

Monday, June 22, 2009

Early Jurassic side-winder - but is it a snake?

Francois Durand's side-winding trace from the Clarens Formation. From Durand (2005.

Discussion about fossil side-winding traces over at Tet Zoo prompted me to get off my butt and actually put something up on this blog.
Its Francois Durand's apparent side-winding trace from the Clarens Formation of South Africa. Not much has been made of this and the only two references to it that I know of are rather obscure so I'm putting it up here to let people know about it.
It certainly looks like a track left by a modern sidewinding viper.

A modern side-winder

Francois made it fairly clear in his presentation of this fossil to the Geoscience Africa conferance back in 2004 that he thought it was made by an Early Jurassic viperid although he only hints at this in the two publications featuring this fossil that I know of. Such an occurence is strongly at odds with the known fossil record of snakes. Even the most primitive snakes don't show up until the Cretaceous, and advanced snakes like viperids don't start radiating until well in the Cenozoic, thus to have a Jurassic Viperid means that just about all tradtional family level clades of snakes have massive ghost lineages stretching back tens of millions of years. The fossil record can be spotty but it ain't THAT bad.
My take is that sidewinding habit may have evolved sporadically from time to time in all sorts of elongate limb-reduced tetrapods when the conditions warranted it. The whole discussion started over the possible sidewinding traces from a Permian, wet muddy, if not aquatic environment that I had a hand in describing.If correctly interpreted sidewinding need not be restrited to dry loose sand, wet sloppy mud might be just as capable of supporting it.
So what was elongate sidewinding tetrapod of the Clarens? We haven't a clue.


Durand, J.F. 2004. The origin of snakes. Geoscience Africa 2004. Abstract Volume, University of the Witwatersrand, Johannesburg, South Africa, pp. 187.

Durand, J.F. 2005. Major African contributions to Palaeozoic and Mesozoic
vertebrate palaeontology. Journal of African Earth Sciences 43: 53-82.