Vega Island

Vega Island is a small island to the northwest of James Ross Island, on the Antarctic Peninsula.

It is one of several islands around the peninsula known as Graham Land, which is closer to South America than any other part of that continent. [ [http://sci.esa.int/science-e/www/object/index.cfm?fobjectid=41768 ESA Science & Technology: Graham Land ] ]

Stone cold bones

Vega Island has a rich trove of fossils, located in deposits which span the Cretaceous and Paleogene (early "Tertiary") periods. This includes the K-Pg extinction event, which wiped out all non-avian dinosaurs. For documenting the consequences of this event, Vega Island is one of the best locations in the world.

The first dinosaur discovered on Antarctica was an armored ankylosaurian, discovered in 1986 on James Ross Island. The second was discovered on Vega Island in 1986 by the British Antarctic Survey. The hypsilophodont, a type of small, herbivorous dinosaur, was discovered in the mudstone of the López de Bertodano Formation. Both dinosaurs were dated to the late Cretaceous.

The anseriform "Vegavis iaai", discovered in 1992 but not prepared for study until several years later, provided the ultimate proof that modern birds lived alongside their non-avian dinosaur cousins. Many Cretaceous birds fossils were suspected to belong to modern orders, but these were little more than single and broken bones. "V. iaai" by contrast is a fine specimen preserved as associated parts of the skeleton. [Clarke "et al." (2005)]

Only three Cretaceous non-avian dinosaurs have been discovered in Antarctica. The last was also discovered on Vega Island, in 1998 by paleontologists from the Instituto Antartico Argentino in Argentina and St. Mary's College in California. They found the teeth of a duck-bill dinosaur. Also known as hadrosaurs, these semi-quadrupedal herbivores are characterized by elaborate chewing mechanisms, similar to modern ungulates. Many also had a crest on the top of their head, which may have been used for complex vocalizations. By the end of the Cretaceous, the duck-bills were the dominant plant-eating animal of North America, and had spread to South America.

Prior to this find, no duck-bills had been found outside the Americas. The find, dating from 66-67 million years ago, just before the K-Pg extinction event, is evidence that a land bridge still connected South America and Antarctica even at that late a date.

Additional finds from the 1998 expedition included a 4 cm (1.6 in) piece of bone belonging to the most ancient Antarctic bird yet discoveredFact|date=November 2007 ; and remains of plesiosaurs and mosasaurs including several juvenile specimens which are quite rarely ever found.

An additional expedition in December 2003 was locked in the ice and rerouted to James Ross Island.

References

* (2005): Definitive fossil evidence for the extant avian radiation in the Cretaceous. "Nature" 433: 305-308. doi|10.1038/nature03150 [http://www.digimorph.org/specimens/Vegavis_iaai/nature03150.pdf PDF fulltext] [http://www.nature.com/nature/journal/v433/n7023/suppinfo/nature03150.html Supporting information]

External links

* [http://www.nsf.gov/news/news_summ.jsp?cntn_id=102864&org=olpa&from=news New dinosaur finds in Antarctica paint fuller picture of past ecosystem] , from the National Science Foundation, February 6, 1998.
* [http://www.nsf.gov/news/news_summ.jsp?cntn_id=108228 Antarctic Researchers to Discuss Difficult Recovery of Unique Juvenile Plesiosaur Fossil] , from the National Science Foundation, December 6, 2006.
* [http://www.dna.gov.ar/CIENCIA/SANTAR04/CD/PDF/108GG.PDF Rocas hipabisales del grupo volcánico James Ross, Isla Vega] (Spanish)