Friday, 28 January 2011

Darwinopterus egg

A pterosaur find in 2009, from the Cretaceous deposits of Liouning Province in North Eastern China, has allowed sex determination in the pterosaur Darwinopterus.  A number of specimens of this pterosaur are known and this recent find has revealed an uncrested individual with a ready to lay egg.

This pterosaur was fossilized after falling into the sea with a wing injury.  The egg clearly makes this a female and as a result, it appears that all of the males sported cranial crests whilst the females were crestless.  If this rule can be applied to other pterosaur species, it may be that many exhibit this type of sexual dimorphism.

Dr Charles Deeming of Lincoln University assisted in the analysis of the pterosaur fossil when it was in the UK. The fossil is currently held in the Zhejiang Museum of Natural History, Hangzhou, Zhejiang province, China.

Lü L., Unwin D.M., Deeming D.C., Jin X., Liu Y. and  Ji Q., 2011, An Egg-Adult Association, Gender, and Reproduction in Pterosaurs. Science 21 January 2011: Vol. 331 no. 6015 pp. 321- 324 DOI: 10.1126/science.1197323

Sunday, 16 January 2011

The buz around a new pterosaur find

 Pterosaur eggs are in the news again.  A specimen egg in the collection of a texas enthusiast, Dr Neal Naranjo, has been scanned to reveal a pterosaur embryo inside.  The egg is destined to be included in the collections of a new museum at Lufkin, Texas.

archaeology news network blogspot

This is an unusual find and it will complement the previous finds from China and Argentina earlier this century.  The images and location details have not yet been published, but when they are available, the study of pterosaur reproduction will be enhanced considerably.  It is clear from the Chinese specimens that pterosaurs had eggs with thin leathery shells.  The Argentine specimen was fossilised amongst juvenile animals which is a strong suggestion of birth and growth in colonies and it is apparent that pterosaurs were hatched with completely formed wings.  Accepting that the shape and proportions of all of the known pterosaur eggs are similar, this small sample of 4 eggs is not enough information to look at variation over time.  The published eggs all come from a period 100-130ma ago, which is a small time window in such a long evolutionary path.