Friday, 30 April 2010

Pterosaurs: Dragons of the Air

Friday 25 June 2010, 10:00am - Sunday 4 July 2010, 20:30pm

The Southbank Centre, Belvedere Road, London is just a short walk from Covent Garden or Westminster and it is within easy access of Waterloo, Charring Cross and Embankment Stations. In late June it is to become home to some of the largest pterosaurs in the UK.
The University of Portsmouth, supported by the Royal Society are participating in the London Summer Science Festival. This exhibition celebrates the 350th anniversary of the Royal Society. The project involves making life size models of pterosaurs and standing them outside the Royal Festival Hall. Some of the models will be suspended in flying poses and others will be on the ground. Mark Witton is the host of this event and his team are working hard to meet the deadline with some well developed modelling techniques.
The frames for the large models have been engineered on the Isle of Wight by Hoverworks and the main structures are carved from Styrofoam. The construction has been filmed by the BBC at different stages of the work, so it seems that there will be a program in the future to document this rather gigantic modelling project. For anyone who is unsure of the size of these large flying creatures, this exhibition will be a real eye-opener. The exhibits include the largest ground standing model of a pterosaur ever exhibited. The only thing that has come close to this is a composite picture that Matt Wedell produced in 2006 which was updated in June 2008 to include a scale drawing of Mark Witton's Hertzagopteryx image. Good old Photoshop!

Images credited to the University of Portsmouth and the BBC.

Tuesday, 20 April 2010

Sculpting pterosaur bones

Bruce Mohn is a palaeo-artist who has produces fine models of dinosaurs and other prehistoric species, including Pterodactylus and Rhamphorhynchus. Many of his works are in museums and I admire his skill and accuracy in portraying these subjects. Above is one of his pictures showing some of the bones of his Rhamphorhynchus model during development.
I thought it would be a good idea to have a go and produce a model of my own. Bruce modelled much of his Rhamphorhynchus bones on R. gemmingi. I thought it would be fun to have a go at another species, R. longimanus (Just because I have lots of photographs).
Having made a basic modelling kit from bits of driftwood and an ice-cream lolly stick, I went out and purchased some modelling clay. The best option seemed a plastic clay which can be baked hard when shaped. There are several types on the market - Fimo is easy to work, but contracts a little when baked. Sculpey requires a bit more skill to work, but has the advantage of retaining its size when baked. It can also be re-baked several times and sanded or carved when set. There are also several types of air dry clay, but you need to be very good to complete a model in one go. I chose Sculpey modelling clay.
The first stage in the operation is to take a small piece of clay and kneed it between your fingers until it is soft. Shape a blank (A) which is the shape you need, but simple in form. Bake at 125°C for 20 minutes (30 minutes for big bits) and cool. The blank shape can be carved and built up using more clay to form the basic shape of the bone (B). This can then be baked again to harden the added detail. Carving, sanding, building up and baking can be done as many times as necessary. The final bake needs to be at 130°C for 30 minutes. If you go any hotter, the structure of the clay will blow out and release gas.
 I was quite please with the final trial model of the humerus. It just needs a little dressing and painting to make a passable display specimen. The quality of my first piece of work does not compare with the professional finish on Bruce's work, but everyone starts as a novice, it can only get better with time.

The Sculpey clay also works well in fairly flat silicon moulds. I have reproduced castings of trilobite specimens using this medium with very good results.

Sunday, 11 April 2010

The Pterosauria

Dave Martill, David Unwin and Robert Loveridge are working on a definitive publication on the order Pterosauria. The text has a significant number of contributions from the leading workers in the field and has a forward by Peter Wellnhofer. It is planned for publication by Cambridge University Press in December 2010 and this looks like a significant "must have" for anyone who is serious about fossil pterosaurs. The pre-order UK price is £80 sterling, though this is projected to increase after publication.
There have been some significant discoveries since Peter Wellnhofer wrote The Illustrated Encyclopedia of Pterosaurs (published in 1991) and this new text should address the later developments in a clear and informed way. Its publication is eagerly awaited.