In 1987 an opal miner in Coober Pedy found an opalised fossil. They were part of the Zorba Extension Opal Field.

In 1988, the chairman of the company Comrealty ("Mr. Sid Londish") bought the specimen. Later that year he donated it to the Australian Museum.

In September 1988, it was prepared by the Australian Museum.

In 2006, Benjamin Kear and colleagues named Umoonasaurus, part of Pliosauroidea and the most basal Rhomaleosauridae.