Dinosaur Cove

This mine has provided valuable information about especially persistent breed of ancient reptiles – Australian polar dinosaurs.

Seaside cliffs with dinosaur bones

First petrified bones of dinosaurs were found in rocky outcrops at the beach west from Inverloch, some 200 km to the east from Dinosaur Cove. This discovery was made in 1905.

Dinosaur Cove was discovered 75 years later – on 13 December 1980. Back then a group of enthusiasts was searching remnants of dinosaurs along the beaches of Victoria already for several years. They had some success – there were made some scattered, interesting findings. But a site in a small cove west from Glenaire was exceptionally rich with remnants of ancient reptiles. On the evening of discovery day, it got named – Dinosaur Cove.

Dinosaur mine

Unfortunately further enthusiasm was stifled by a quick assessment of chances to get the bones out of cliffs: fossils were concentrated in a narrow strip in up to 0.3 m thick layer. This layer was at the base of the cliff, up to 90 m high and consisting for the most part, of hard rocks. The narrow strip was directed inside the cliff. Even access to this site was risky.

Thus researchers decided to look for some other dinosaur site that would be easier to mine. For some years – until 1984 – Dinosaur Cove was silent but this rich find of unknown beings was not forgotten. A large group of volunteers, some miners, and paleontologists led by Patricia Vickers-Rich and Thomas H.Rich made a desperate attempt to cut through the hard rock. Over 16 days they managed to carve through some tons of rocks. This hard work paid off – there were found 80 dinosaur bones.

Since then there was started real mining of dinosaurs. Works are ongoing nearly every summer, numerous volunteers and heavy equipment are involved. 1 kg of fossil-bearing rock requires the removal of approximately 30 kg of hard rock above it. Work is permanently led by Patricia Vickers-Rich and Thomas Rich.

Geological records of Gondwana times

The valuable fossil finds here are confined to the sandstone of the Lower Cretaceous period, they are 100 – 110 million years old.

The enormous southern continent – Gondwana – was breaking up at this time. Australia still was united with Antarctica but there was forming a rift valley already. Present-day Dinosaur Cove most likely was a small stream that collected bones of smaller animals and covered them with silt.

Later these deposits went below sea level and were overlaid with later sediments. As time went by, sediments were petrified and over the last 30 million years are lifted above sea level again.

Dinosaurs in polar night

Present-day Dinosaur Cove was inside the Antarctic circle and this was the first location where polar dinosaurs were discovered. Although the climate back then was warmer than today, dinosaurs living here knew quite well what is snow, ice, and polar nights.

This has led to theories that these reptiles developed such adaptations as good night vision and that they were even warm-blooded. This has pushed the imagination of some specialists even further – maybe the specific adaptations of Australian dinosaurs that allowed them to survive the Cretaceous-Tertiary extinction event? Thus far no evidence for this has been found but the search is on.

Herbivorous dinosaurs of Dinosaur Cove

Several new species have been discovered in Dinosaur Cove, including:

• Leaellynasaura amicagraphica was discovered in 1989 and is named after Riche’s daughter Leaellyn. Leaellynasaura was small, up to 90 cm long reptile with comparatively large eyes – most likely accustomed to life during the polar night.
• Timimus hermani has been desribed after two upper leg bones in 1993. This dinosaur is named after Riches’ son Tim. This reptile lived 106 million years ago and, according to hypothesis of Anusuya Chinsamy, possibly hibernated during the colder winter months.
• Atlascopcosaurus loadsi Rich & Vickers-Rich, 1989 – named after Atlas Copco Company – provider of equipment which was essential in finding the fossils. This quick reptile was 2 – 3 m long, weighing approximately 125 kg, lived during the early Cretaceous.

First southern Tyrannosaur

Before March 2010 it was considered that tyrannosaurs evolved and lived in the northern hemisphere. History of geology, for the most part, has been made in Northern Hemisphere and dinosaurs were no exception – first and most finds took place in the north – in North America, China, Mongolia, Kazakhstan, and elsewhere. Over the last decades, the situation changed though – more and more finds were made in the southern hemisphere, most "northern" dinosaurs were found in the south as well.

Tyrannosauridae though was one of exceptions thus far. This family of ancient reptiles is much sought and well researched due to a comparatively good state of conservation and – also their fame in popular culture.

In March 2010 international group of scientists announced a find of the very first tyrannosaur in the Southern hemisphere – this discovery was made in Dinosaur Cove. Here was found some 30 cm long hip bone, belonging to an ancestor of Tyrannosaurus rex.

Tyrannosaur of Dinosaur Cove was approximately 3 m long, weighing some 80 kg, and possibly had the large head and small arms characteristic for these reptiles. Thus it was considerably smaller than the famous 13 meters long Tyrannosaurus rex weighing up to 7 tonnes. But Australian reptile lived 110 million years ago, while Tyrannosaurus rex lived "only" 70 million years ago.

Find of Dinosaur Cove belongs to early tyrannosaurs and currently is far away from the other known finds of these carnivorous dinosaurs. This hints at possible future discoveries of these ancient reptiles in Africa, South America, and India.

References

1. Thomas H. Rich, The Discovery of Dinosaur Cove. A History of Museum Victoria. Accessed 29.03.10.
2. First Ever Southern Tyrannosaur Dinosaur Discovered. ScienceDaily, 26 March 2010. Accessed 29.03.10.
3. Diggers at Dinosaur Cove: Not all dinosaurs lived in hot, lush surroundings. Archaeologists in Australia are discovering remains that challenge ideas about the way the giant reptiles lived and died. 13 February 1993 by Ian Anderson. Accessed 29.03.10.