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

Tuesday, 17 September 2013

Pterosaur toy

This 8cm high orange wind up hopping dinosaur toy is distributed by H. Grossman, the Scottish Dinosaur Toy company.  You wind it up and it hops for a good few seconds.  No pterosaur enthusiast worth their salt should be without one.  It has kept our cats amused for seconds.

Friday, 7 June 2013

Can You Help

Isidro Martínez has just sent me a photograph of a pterosaur skull in the Museum Mensch und Natur in Münich, Germany.  It displays a very good crest and the teeth are preserved mainly in situ.
The fossil is new to me and I would like to know more about it.  The museum display has no label or information and I have been unable to contact the staff directly. Can any one help with information on the specimen?

Sunday, 12 May 2013

Axial Skeleton

Recently, I have been asked to identify a number of pterosaur vertebrae.  Most of them were of small theropod dinosaur cervicals from the Kem-Kem formation in Morocco.  Pterosaur vertebrae in isolation requires a skilled eye to identify them, so I thought it would be a good idea to look at the axial skeleton of Pteranodon as the vertebrae are quite well documented.  I am going to gloss over the pectoral and pelvic girdles here.

This is a drawing from the website of the combined atlas and axis and the first cervical vertebra of pteranodon.  It is based on a drawing by Eaton.  Notice the pneumatic foramen (pn) where an air sac tube would pass to permit the interior of the bone to be filled with air.  This considerably lightens the skeleton for flight - pneumatic bones are also found in theropod dinosaurs like T-Rex and in the suropods.
The dorsal vertebrae of most pterosaurs are very short and have attachments for ribs.
Sacral vertebrae are fused and support the pelvis.  There are no articular surfaces and the vertebrae are joined by suture jointing, known as ankylosis.
Caudals are short and uninspiring and often look like the caudals of many other species, so in isolation they are indistinguishable from ichthyosaurs and many other large vertebrates.

The axial skeleton is seen to be arranged in functional sections.  The pectoral and pelvic girdles have been omitted here.

Ax is the combined atlas and axis which joins the spine to the skull.  This was quite a solid bone.

A shows the cervical vertebrae that make up the neck.  In Pteranodon, these were sturdy and had large dorsal spines to anchor the muscles that positioned the skull, with its large occipital head crest.  The joints had a good range of movement.

B is the Notarium.  This is a region of the spine where the thoraxic vertebrae are ankylose and support a fused region of bone that articulates with the scapulae.  The scapulo-coracoid is a strong bone that was anchored at the notarium and the sternum.  This forms the pectoral girdle which had to take the strain of the wings in flight.

C is a region where the dorsal vertebrae are not fused.  This region gave a small amount of flexion between two very solid and rigid regions of the back.  These few vertebrae held floating ribs.

D is the sacral region.  Like the thoraxic vertebrae attached to the notarium, the sacrals were fused and attached to the pelvis.

E In pterodactyloid pterosaurs, the caudal vertebrae were simple and very lightly muscled.

Half of the length of the axial skeleton in pteranodon is neck.  The neck is of a similar length to the skull.  The spine behind this region is mostly rigid, forming a solid box which gives the skeleton a sturdy structure to stabilise the wings in relation to the body, when the animal is in flight.  This was a very well adapted animal for flight.

Most large pterosaur axial skeletons show close similarities to pteranodon.  Most of the small pterosaurs also have these overall features, with minor variations.  This type of spine is essential for flying animals and this principle structure is also seen in all flying birds.

Thursday, 11 April 2013

The Legal Deposit Libraries (Non-Print Works) Regulations 2013

There is a paper being reviewed in Parliament which may have an impact on anyone who publishes on-line in the UK.  The regulations are currently in draft form and may be due to amendment before being put on the statute books.

The Legal Deposit Libraries (Non-Print Works) Regulations 2013 should clarify the requirements of non-printed deposits within the UK.  This legislation is expected to have an impact on publications made via websites and downloads.  At present, it looks as if such publications will require an ISBN number, but it is unclear if this applies to all such publications or to future publications.

The Pterosaur Database is reviewing some of its pages in case there is a legal requirement to record and declare downloads to a central repository.  The current legal repositories are:
  • British Library (“BL”)
  • Bodleian Library, Oxford (“Bodleian”)
  • University Library, Cambridge (“CUL”)
  • Library of Trinity College, Dublin (“TCD”)
  • National Library of Wales (“NLW”)
  • National Library of Scotland (“NLS”)
The new legislation will, in its present form, permit harvesting of documents from the Internet to the repositories for archiving and for public access at the repositories.  There is an issue that sales of texts and DVD/ music downloads need protecting, but this is not finalised at this point.

The Pterosaur Database has undergone a global update in the last 2 weeks to ensure that the bulk of its content is current.  many thanks to the work of Hike Hanson for his species list, which has formed a key part of the update.  Also thanks to Lorna Steel for her listing of the NHM London specimens which has allowed me to update this important collection. There are some issues over consensus in some of the updates, but the classification of pterosaurs has always been in a state of flux, so the data needs to be viewed as a guide rather than a final version.

Monday, 4 March 2013

On-Line Museum Lists

This week I finally got around to writing the software for the museum collections listings.  The pages will generate a list of all specimens held on The Pterosaur Database for museums selected, to give a workable listing.  The non UK museums may be type and figured specimens only in some cases, until the lists are updated.
To search for museum specimens on-line, the user will be asked for the country name.  This should be entered in English wherever possible.
On select, the list of museum names on the database will be presented for that country.  If there is a null return, the country has no holdings that are recorded.  Simply choose the number against the museum and enter it into the box at the end of the listing.  Pressing select will generate a list of all specimens recorded on The Pterosaur Database against that museum.
For some collections, the list may be quite long.  In the case shown, there are 104 specimens listed.
The old museum listings are still available, but they will no longer be updated.  Like all of the searches on The Pterosaur Database, the data displayed is ephemoral.  It can be printed or copied and pasted, but it cannot be saved to disc.
If anyone wishes to include data that is not held, then it can be sent by E-mail or added to the speciens pages for inclusion.

Wednesday, 16 January 2013

School Pages update

 The schools pages for The Pterosaur Database were assembled in a hurry from scraps and bits of other website material.  I have now rewritten the pages to give some basic and useful information based on previous student enquiries.
 The pages are basic, but they are intended to be presented in  a simple to understand format.  For more detailed information, The Pterosaur Database main pages are available, but there is an assumed knowledge for the main pages and some students may need to use the simple format for basic knowledge first.
The additional update is one I have been meaning to do for some time.  More images have been added to the Free Download page to allow students to enhance their coursework with useful and approved graphics.  These pages may be developed over the next few months to include simple PowerPoint presentations and downloadable text worksheets.

Friday, 4 January 2013

Fractured Wing Bones

A number of wing bone fractures are known to have occurred in pterosaur specimens around the wrist area (Wing metacarpal and first phalange joint).  I have puzzled over why this should be the case and have not found a satisfactory explanation until now.
This Pterodactylus from the Solenhofen Limestone in Bavaria shows a fracture of the first wing phalange near to the joint with the wing metacarpal.  This appears to be a stress fracture at a weak point in the bone.  It is not typical of a failure that would occur during flight or in  predatory conflict.
The same type of fracture can be seen in the X-ray of this Tapejarid fossil, where the wing metacarpal has been broken near to the joint.  Such fractures would have collapsed one wing, making it impossible to fly.  If this type of fracture occurred causing the pterosaur to fall into water, the injury would probably have been fatal.  In both of these cases, the fracture resulted in the death of these animals.

Similar fractures can be seen on isolated bone ends of medium sized pterosaurs.  These fracture patterns are not uncommon across the order as a whole, but are seldom seen in smaller individuals.

Mike Habib has been postulating the use of quadrupedal launching for large pterosaurs for some time now and his ideas are received with some caution.  However, the biology and anatomical structure of the wing bones in such a launch would impose stress on the bone structures which, in some cases, would explain their occasional fractures.  I consider it unlikely that pterosaurs would use this launch method across all genera as a prime method of launch, but the functionality and energy conservation of such a launch method seems to me to suggest that many species of pterosaur could take advantage of this type of take off strategy.

From my own experiments with pterosaur wing efficiency in gliding, it is clear that this method of launch is very practical, especially in species with larger wing areas and larger wing spans.  It also seems that apparently older animals have relatively thinner bone cortex thickness to bone diameter ratios, making the bones more likely to be affected by take-off stress in quadrupedal launch.

I do not have conclusive data on this matter, but there is a potential thesis here for someone intent enough to take on the task.

Habib M. B., 2008, Comparative evidence for quadrupedal launch in pterosaurs. P161-168, In: Flugsaurier: Pterosaur papers in honour of Peter Wellnhofer. 2008. Hone D. W. E. and Buffetaut E. (eds). Zitteliana B, 28. 264pp

Habib M., 2011, Solving the pterosaur size problem: Quadrupedal launch in the Pterosauria, Los Angeles County Museum