Thursday, 15 October 2015

Humerus crests

The large deltoid process in pterosaur humeri show a great degree of variation between species and families.  Early Rhamphorhynchoid species tend to have deep, long and flat deltoid processes whilst later species show a narrowing and extending of this process.  Later pterodactyloid species tend towards a curved deltoid process on the Humerus.
This shows an example of some of the types.  Two later pterodactyloid species on the left and three earlier Rhamphorhynchoid species on the right.
These examples of early Rhamphorhynchoid humeri show the simple joint structures and the flat profile of the deltoid crest
By contrast, the humeri of larger pterodactyloid species show a different structure.  The joint surfaces are more complex and the deltoid crest is far from flat, showing a curved shape with a pronounced articular surface.
The curved shape of the deltoid crest can be seen in these images.
Pterosaurs were a very diverse order of animals, showing a vast variation of forms across millions of years of time.  As they became more specialised, the skeletal structures showed more complexity.  Many of the structural bones of the skeleton demonstrate variation in this way, less so in the wing phalanges.

Monday, 20 April 2015

Web server issues

The Pterosaur Database has experienced a server file loss on the morning of the 19th April 2015.  The cause was an internal problem. About half of the files have been restored and the site is working in part.  It is hoped that all function will be restored in the next two days.  Alas, there is no backup server for this "free to use" site.

2 days on:  The server content has been restored to last months state, with recent files being updated manually.  I hope I have restored all of the files that were absent, but there may be issues with some missed updates.  It is unlikely that this technical failure will be repeated. I took the option of a server side recovery as a total reload would have used up vast amounts of upload time  (15 minutes as opposed to 26 hours).  All seems well so far.

Tuesday, 7 April 2015

The bare bones

Anna Chekovsky has requested permission to translate some of the pages of this blog into French at http://www.teilestore.de/edu/ .  Initially there was an issue with copyright of images and permissions had to be sought.  In the process, this put me back in touch with Bruce Mohn, the well renowned skeletal reproduction sculptor.  His portfolio of work has expanded considerably since 2009 and I am very impressed by the superb quality of his models.
 His model of Pterodactylus Antiquus represents a skeleton based on several good specimens of this, the first known pterosaur species, giving it a very modern stance based on current research.
Equally, the model of Rhamphorhynchus muensteri is a classic reproduction sculpture of the famous Solnhofen Slate pterosaur skeleton.
I am now starting to develop pages based on people who are able to offer such items as would grace any museum of repute.  The reproduction pages are hopefully going to develop as time progresses.

http://www.pterosaur.org.uk/PDB2012/M/reproductions/ReproIndex.htm





Friday, 13 February 2015

Wisbech and Fenland Specimens

Wisbech and Fenland Museum was first opened in 1847 in its present form.  It is amongst the oldest purpose built museums in the UK and the character of its galleries are typically Victorian in essence.  However, the museum functions as a sophisticated modern organisation in all other respects.  This is a museum not to be missed if you are within travelling distance.
Behind the scenes there are a few fragmentary pterosaur bones within the collections.  They are not remarkable, but such fragments should not be forgotten as they may help shed light on other specimens, as yet unknown.
This pelvic bone fragment has only its original label for information.  It is most likely from a large Rhamphorhynchoid pterosaur from the Middle Jurassic age.
Here is a bone that has its extremities missing.  Such specimens are very difficult to identify beyond the anatomical position of the bone on a skeleton.
Here is a more complete and much more finely preserved bone which shows some similarity with Dsungeripterid pterosaur bones.  More work is needed here.

J317-Pterodactylus longicollum  Wing metacarpal (right)
J319a-Rhamphorhynchoid sp  Wing metacarpal (proximal)  
       about 50% of length of bone, Stonesfield Slate 
J319b-Rhamphorhynchoid sp  Wing metacarpal 
       (shaft fragment), Stonesfield Slate
J320-Rhamphorhynchus sp  Humerus (left, dorsal aspect),
      
Stonesfield Slate
J321a-Rhamphorhynchoid sp  Tooth,
Stonesfield Slate
J321b-Rhamphorhynchoid sp 
Tooth, Stonesfield Slate
J321c-Rhamphorhynchoid sp  Scapula
, Stonesfield Slate

      -Indeterminate  Pubis (of a large pterodactyl), Stonesfield Slate
      -Indeterminate  Wing metacarpal (fragment)
, Stonesfield Slate


The Stonesfield Slate is a deferred deposit which contains a significant number of fragmentary fossils that are Middle Jurassic in age. Pterosaurs from this age are very rare and not well studied compared to those of other geological ages.

Monday, 24 November 2014

Avatar in fossil form

A new pterosaur find has just been published and named Ikrandraco avatar.  The creature has a long skull with teeth and a sturdy lower mandibular keel.  Two specimens have been found and the paratype IVPP V.18406 is illustrated.  The holotype IVPP V.18199 is a more complete specimen, but the skull preservation is overlaid by other bones.

Wang X., Rodrigues T., Jiang S., Cheng X. and Kellner A. W. A., 2014, An Early Cretaceous pterosaur with an unusual mandibular crest from China and a potential novel feeding strategy. Scientific Reports, 4/6329, doi:10.1038/srep06329
The name "Ikran" and "avatar" were chosen as the fossil skull shows similarities with the head shape of the fictional Ikran (mountain Banshee) from the science fiction film Avatar.

http://www.avatarmovie.com/index.html

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.