Umoonasaurus
Encyclopedia
Umoonasaurus is an extinct genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of plesiosaur
Plesiosaur
Plesiosauroidea is an extinct clade of carnivorous plesiosaur marine reptiles. Plesiosauroids, are known from the Jurassic and Cretaceous Periods...

 belonging to the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Leptocleididae
Leptocleididae
Leptocleididae is a family of small-sized plesiosaurs that lived during the Early Cretaceous period . Leptocleidus and Umoonasaurus had round bodies and triangle shaped heads. Hilary F. Ketchum and Roger B. J. Benson , transferred Brancasaurus, Kaiwhekea, Nichollssaura and Thililua to this family...

. This genus lived approximately 115 million years ago (Aptian
Aptian
The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous epoch or series and encompasses the time from 125.0 ± 1.0 Ma to 112.0 ± 1.0 Ma , approximately...

-Albian
Albian
The Albian is both an age of the geologic timescale and a stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early/Lower Cretaceous epoch/series. Its approximate time range is 112.0 ± 1.0 Ma to 99.6 ± 0.9 Ma...

) in shallow seas covering parts of what is now Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

. It was a relatively small animal around 2.5 m (8 ft) long. An identifying trait of Umoonasaurus is three crest-ridges on its skull.

Umoonasaurus is known from a relatively complete skeleton preserved as opal from Coober Pedy in South Australia. This specimen was prepared by Paul Willis at the Australian Museum, Sydney, and became the focus of a nationwide fundraising appeal coordinated by ABC TV's Quantum program.

External links

  • http://www.livescience.com/animalworld/060707_aquatic_reptile.html
  • http://www.journals.royalsoc.ac.uk/media/public/contributionsupplementalmaterials/8/3/n/1/83n10t6p17011132/archive1.pdf
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