Incredible opalised dinosaur teeth found in the Outback shed new light on how three giant beasts weighing 90,000kg and measuring 40m coexisted in Australia

• Fossilised dinosaur teeth were found at Lightning Ridge, in north-west NSW 
• Researchers said the area has yielded a rich bounty of fossils over the years
• Three sauropod species are believed to have co-existed in the area at the time

An incredible discovery of fossilised dinosaur teeth offer a fresh insight into how three sauropod species lived in Australia millions of years ago.

The teeth were discovered at Lightning Ridge, a small outback town in north-western New South Wales, near the Queensland border.

Researchers from the University of New England said the area has yielded a rich bounty of dinosaur fossils over the years, and is unique in that all of the fossils found there are completely formed in opal.

Sauropod species include dinosaurs such as Brontosaurus and Brachiosaurus - two of the largest beasts to have walked the earth weighing in at 90,000kg and measuring 40m long.

Although their fossils are common in central Queensland, there has been limited evidence of their existence and lifestyle from NSW. 

Timothy Frauenfelder, lead researcher and PhD candidate said: 'Teeth are one of the smallest bones in a sauropod and there is an abundance of them at Lightning Ridge. 

'Although small in comparison to other sauropod fossils, which can be over one metre long, teeth can be incredibly useful in assessing ecology and diversity.

'Unlike us, sauropod dinosaurs don't have different types of teeth such as molars or incisors, and differing tooth shapes can give us an idea about how many species were living in a particular area.' 

This led researchers to conclude three species co-existed in the area.

The team also conducted a microwear analysis to view feeding features preserved on a tooth's wear facet.

'As sauropods eat, they produce large facets that preserve varying degrees of features such as pits and scratches,' Mr Frauenfelder said. 

'The frequencies of these features enable us to determine how high an animal was feeding in the canopy, or how hard the food was. 

'Comparing features between teeth, allows us to interpret how these giant dinosaurs co-existed.'

Mr Frauenfelder was able to determine that at least two of the species fed at different levels within the canopy.

One species fed at ground levels - less than one metre above ground - while the other was feeding mid-canopy, or one to 10 metres above ground. 

The study was published in the Journal Lethaia.