Sunday, 10 August 2014

Wow!

A recent paper published this year has revealed a wealth of pterosaur information from one find.  A bad weather event about 120 million years ago preserved the remains of 40 pterosaurs of a single colony along with 5 eggs.
Found at a site in the Turpan-Hami Basin near the Tian Shan Mountains in Xinjiang, China, this skull is a complete one of an assumed female specimen of Hamipterus tianshanensis.  It clearly shows a shallow crest and a pterodactyloid structure to the skeleton.
Remains of other individuals show a more prominent nasal crest and these are presumed males, consistent with the evidence found in Darwinopterus regarding male-female sexual dimorphism.
Alongside the remains were 5 pterosaur eggs, preserved in full form.  They have thin, soft, calcareous shells and a sturdy membrane on the inner side of the shell.
This find has been well studied by some of the biggest names in pterosaur research and it is a landmark find.  This is clear evidence of colonial behaviour and flocking in pterosaurs.  It also reinforces the ideas that some species display sexual dimorphism and it associates eggs with adult and sub-adult animals.
These specimens are now in the Beijing Palaeontology Museum (IVPP).

Wang X., Kellner A. W. A., Jiang S., Wang Q., Ma Y., Paidoula Y., Cheng X., Rodrigues T., Meng X., Zhang J., Li N. and Zhou Z., 2014, Sexually Dimorphic Tridimensionally Preserved Pterosaurs and Their Eggs from China, Current Biology. doi: 10.1016/j.cub.2014.04.054

Wednesday, 11 June 2014

Changes to the blog

Google - who host blogger - are making changes to their services.  Access to Google services is now going to be through @gmail accounts.  There has been no notification to weblog administrators about the change, but I have taken the precaution of assigning a Google Mail administrator for this blog to ensure that it will function when the changes are applied on ;
16th June 2014
 Lets hope all goes well.

Thursday, 1 May 2014

The Rotunda

 Scarborough Museum Services have been restructured over the past decade.  The geology collections are now housed in the Rotunda Museum at the end of Valley Road.
 Amongst the collections are two bones collected from the Taynton Limestone.  This one is catalogued SCARB-2000-1883 and carries a label 26G and another old hand written label "Bone of A Pterosaur".  This bone is a proximal Humerus from an unidentified pterosaur species.
 The second bone is catalogued SCARB-2000-1970 and has an old hand written label "Bones of Pterodactyl".  This is a rhamphorhynchoid wing metacarpal of an Middle Jurassic pterosaur.
A third specimen is on display and this is the Cast of the Pterodactylus antiquus specimen from Mannheim.  This was the first pterosaur to be published by Collini in 1784.

The Rotunda Museum is well worth a visit if you are in the Scarborough area.  It has very well organised displays and a wealth of local Jurassic material.  There is also a lot of information about the people who collected and published work on the specimens from the Yorkshire coast.

http://www.scarboroughmuseumstrust.org.uk/ 

Just a few streets away on Eastborough is Richard Widdowson's "Gems" shop where there are exceptional quality local fossil specimens for sale.  This fossil coast has some interesting geology and archaeology which should not be missed.

Saturday, 15 March 2014

The power of X-rays

It is often the case that fossil specimens are preserved within a matrix of rock where some parts lay over other parts. In the case shown below, the skull of this pterosaur is laying across the wing bones. Without some form of scan, the skull would have to be removed to see the bones below.
An X-ray of the fossil matrix can, in many cases, reveal the bones that are concealed below the skull. X-rays of fossils depend upon variations in radio-density of the materials. If the fossil bones are replaced with different material than the surrounding matrix and have variations in density within the structures themselves, an X-ray can reveal quite a lot of detail.
Interpretation of X-rays is quite a skilful task. analysis of detail requires a great deal of knowledge about the nature of the materials that the X-rays are passing through. The analysis of this X-ray shows the interpreted wing bone positions marked.
It shows in this case, that the Wing Metacarpal has sustained a stress fracture, probably during launch for flight. This break does not have the radial signature of an impact fracture and it was probably caused by the bone at the point of fracture being too thin to sustain the stress of extreme latteral pressure. If this animal fell into the sea with one wing broken in this way, it would be unable to take off and would probably have starved to death or become a victim of small marine carnivores picking at its flesh.  There is no lower jaw associated with these remains, so that probably detached prior to fossilization.
The fossil X-ray will only show the preserved hard parts of an animal. The use is very limited, unlike this X-ray of one of my cats, which shows a good deal of soft tissue structure and variation in bone density where the bones are in their living orientation.

Wednesday, 18 December 2013

Pterodactyl Bookmark

 This little offering came from Webberleys bookshop in Hanley, Stoke-on-Trent.  It is by Cool Creations Ltd, Rudgate Business Park, Tockwith, York, YO26 7RD.  Most good bookshops should have one.

Monday, 21 October 2013

Thoughts on a head crest

 The skull of Tapejara wellnhoferi has bony extensions to the upper and lower mandible and a long spinous bone extending back over the top of the skull.  There is no evidence of soft tissue crests in this species, but since the other tapejarids; Tupandactylus navigens and  Tupandactylus imperator have soft tissue crests it is probable that T. wellnhoferi also had a soft tissue crest.
We can speculate that without the bony spine above the mandible, the crest would need to be small, or flexible.  Perhaps it was inflatable using blood or air sacs.  This would be an interesting notion!
As soft tissue is seldom preserved and in the case of pterosaurs, occasionally seen as just a residue with no structural detail preserved, any speculation could be valid.
Many illustrators see colour preserved in these crests.  I am not sure of this and it seems more likely that the difference in colour seen in some fossils may actually be an artifact of the preservation.  The impression of colour is more likely to be due to differences in tissue density, tissue type or the chemistry of fossilisation.  Give a thought to the scientists who have to interpret this evidence.  It is easy to see things that are not there, just to make sense of the evidence that is there.  Anyway, I like the thought of pterosaurs being able to fold and display soft tissue crests, even if the evidence is not present in the fossil record - or is it?

Friday, 11 October 2013

Royal Mail Dinosaur Stamps

 The Royal Mail have issued their dinosaur stamps.  Fist day covers were only available at Post Offices on 10 Oct 2013, but the stamp sets are still available where stocks last.
 The art work on these stamps is by John Sibbick.  His work is found in many pterosaur publications.  Text on the cover card is by Angela Milner from the NHM London.  There are two pterosaur stamps in the set of 10 fist class stamps.  It is interesting that all of the stamps have an area of printed image that extends beyond the normal edge of the stamp, requiring a special perforation cut for the sheets.
 Ornithocheirus represents the pterodactyloid pterosaurs. This species was first described by Harry Govier Seeley in 1869, though the fossils had been known of since 1827.
Dimorphodon represents the older rhamphorhynchoid pterosaurs and was described by William Clift and William John Broderip in 1835.  This description was based on a fossil that was discovered by Mary Anning in 1828.

These stamps are available over the counter at all UK post offices whilst stocks last.

Royal Mail Collectible stamps