Iberomesornis

From Wikipedia, the free encyclopedia

Iberomesornis Fossil range: Early Cretaceous
Reconstruction of Iberomesornis (Museo Nacional de Ciencias Naturales, Madrid)
Scientific classification
Kingdom: Animalia Phylum: Chordata Class: Aves Subclass: Enantiornithes Order: Iberomesornithiformes (disputed) Family: Iberomesornithidae Genus: Iberomesornis Sanz & J. Bonaparte, 1992 Species: I. romerali
Binomial name
Iberomesornis romerali Sanz & J. Bonaparte, 1992

Iberomesornis ("Spanish intermediate bird") is a monotypic genus of enantiornithine bird. In 1985 it was discovered in the Early Cretaceous La Huérgina Formation at Las Hoyas, Cuenca (province), Spain. Iberomesornis lived during the Hauterivian and Barremian roughly 137-121 million years ago. The Huérgina Formation was once a forest surrounding a lake. Iberomesornis romerali was more advanced physically than Archaeopteryx. Most other birds from this time (around 135 million years ago) have reptilian characteristics, such as a long tail. Yet the vertebrate column of Iberomesornis ended in a pygostyle: a splint of bone made of fused tail vertabrae that supports the tail feathers. Its wings still sported claws, but the thumb claw was reduced. Its ribcage was not strengthened by uncinate processes.

Iberomesornis was quite small - growing to a wingspan of 10-15 centimeters and weighing 2 ounces. Overall it was no bigger than a large modern sparrow, but it was an accomplished flyer, and probably hunted insects and small animals, plucking them out of the air or from the ground. It may have preferred to live near to lakes, catching insects from the water's surface. Despite being able to perform many aerial feats, such as turning and swooping at speed, it probably couldn't manoeuvre at slow speeds. When resting, it used its long, clawed feet to perch on branches. It is unlikely to have been able to sing, although it could probably have made basic squawking noises.

Since the skull is not known intact, its diet remains a subject of guesswork. Since the discovery of Iberomesornis, many more enanitiornithine fossils have come to light in the quarries of Liaoning provice, China. Well preserved specimens of Chinese species such as Sinornis and Confuciusornis have permitted scientists to understand the birds' early fossil history.

[edit] Popular Culture

They appeared in the BBC series Walking with Dinosaurs, where they were depicted as having bright blue feathers.

[edit] References

• Haines, Tim & Chambers, Paul. (2006): The Complete Guide to Prehistoric Life. Canada: Firefly Books Ltd.
• Sanz, J. L. & Bonaparte, José F. (1992): A New Order of Birds (Class Aves) from the Lower Cretaceous of Spain. In: Jonathan J. Becker (ed.): Papers in Avian Paleontology Honoring Pierce Brodkorb. Natural History Museum of Los Angeles County Contributions in Science 36: 38-49.