Dinosaur Cove is located in the south-east of the Australian continent, where the Otway ranges meet the sea to the west of Cape Otway, along the Great Ocean road. The fossil bearing rock layers consist of sand-, silt- and mudstones that have been dated to around 106 million years ago (MYA). Because of the hardness of the rock, heavy mining equipment and dynamite was required to uncover the rock layers that contained fossils. Since the layers of rock that contained the fossils formed part of a cliff, fossil remains had to be excavated by tunneling into the cliff face, requiring the specialized knowledge of miners and explosives experts who volunteered their time and services. One of the dinosaur species recovered from the site, Atlascopcosaurus loadsi (a hypsilophodontid dinosaur), was named after the mining company that donated some of the equipment, Atlas Copco, and after Mr William Loads, a former employee of the company.
There are three fossil beds that have been worked at Dinosaur Cove: Dinosaur Cove West, Dinosaur Cove East, and Slippery Rocks. All of them are virtually inaccessable without either climbing down dangerous cliffs or landing a boat or helicopter on the rock platforms during low tide. None of the sites are currently being worked.
During the Early Cretaceous the area around Dinosaur Cove was a flood plain within a great rift valley that formed as Australia tore northward from Antarctica. Sand, mud and silt was deposited by streams and rivers, covering the remains of dead animals and plants and eventually preserving some of them. The deposits were buried by up to three kilometres as the rift valley sank, turning the sediments into rock. In the last 30 million years the sediments have been uplifted to form the Otway and Strzeleki ranges, bringing them to the surface again.
Dinosaur Cove has yielded such species as Leaellynasaura amicagraphica and Atlascopcosaurus loadsi (all hypsilophodontids), Timimus hermani (thought to have been an ornithomimosaur, now Coelurosauria incertae sedis), as well as fragments of what may be a Caenagnathid (relatives of the Oviraptors).
Strzeleki Ranges, Victoria
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The Strzeleki ranges formed at about the same time as the Otway ranges were uplifted, although the fossil bearing layers of rock are slightly older at around 115 MYA. The rocks that form the Strzelecki Group, of which Flat Rocks is a part, are visible along a 50 km stretch of coastline. There are seven main sites from which fossils have been excavated, starting from west to east: the San Remo Site, the Punchbowl Site, The Arch Site, the Blackhead Site, the Powlett River Site, the Eagles Nest Site, and Flat Rocks. Most date to around 115 million years, with the exception of the San Remo and Punchbowl deposits that are around 5 million years older.
The first dinosaur bone found in Victoria was a toe claw from a small theropod dinosaur that was taken to England and described by William Fergusson in 1906. It was discovered in coastal rock platform deposits at Cape Patterson, close to the currently worked Flat Rocks site (near Inverloch). The deposits the claw was found in have since been relocated, and the "Fergusson Site" as it is known is yielding some promising material of its own. Eleven specimens were collected during the 2001 season, including a 15mm plesiosaur tooth.
The main fossil bearing strata at Flat Rocks (the main site still being worked) are only accessable for three to four hours a day during low tide. With each high tide the excavation in the rock was becoming filled with sand, and by the 1997 season the hole had become so big that it was taking more than two hours to clear it out before any actual palaeontological work could begin. In 1998 a new system of tarpaulins, plastic containers and steel mesh was employed to fill the hole before the tide returned to keep most of the sand out, significantly reducing the length of time required to prepare it for further excavation.
During the 2000 season over a thousand bones and teeth were recovered and catalogued from Flat Rocks. The fossils include the remains of several types of dinosaur (hypsilophodontids, large and small theropods, ankylosaur teeth and dermal ossicles), birds, pterosaurs, turtles, fish, and mammals. The earlier deposits of the San Remo and Punchbowl sites are also known for their labyrinthodontid remains - giant amphibians related to salamanders that filled a similar niche to crocodiles.
Hypsilophodontids make up the majority of dinosaurs found at Flat Rocks. Most of the fossils are of individual bones, however some have proved diagnostic enough to be classified to the generic level, and one, Qantassaurus inexpectus, to the specific level. Other hypsilophodontid genera include Leaellynasaura sp, Atlascopcosaurus sp, and Fulgurotherium sp. The first two genera are based on holotypes from the Dinosaur Cove sites in the Otway Group, with the third (dubious) genus originally known from the opal fields of Lighting Ridge in New South Wales. Qantassaurus is so far only known from the Strzelecki Group deposits.
Theropod remains are also known from the Strzelecki Group of sites. Numerous small dromaeosaur-like teeth have been recovered, which have serrations only on the posterior edge. A claw and part of a pelvis have been tentatively assigned to the ornithomimosaurs. A megaraptoran astragalus was recovered in 1979 that may be a close relative of Australovenator from Queensland. A partial manual claw, around 15 cm in estimated total length, indicates that large theropods were also present in the area.
The 1997 season yielded an embryonic hypsilophodontid femur, a possible small pterosaur bone (a metacarpal or metatarsal), and the first Early Cretaceous mammal remains from Victoria (Ausktribosphenos nyktos) which may be one of the world's oldest placental mammal fossils. A second Ausktribosphenid mammal, Bishops whitmorei has also been described, as well as the monotreme Teinolophos trusleri.
The "Fossil Triangle", Queensland
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Some of the most complete dinosaur remains have been recovered from an area of outback Queensland know as the "fossil triangle", a roughly triangular area connecting Winton, Hughenden and Cloncurry. This area was part of a shallow inland sea around 115 MYA (the Early Cretaceous), and hence most of the fossil remains are to be found in soft marine limestones that are far easier to extract fossils from than the hard stone that encases fossils in Victoria. Limestone can be dissolved using a weak acid (usually acetic acid, the main ingredient of vinegar) to free the more acid resistant fossils inside. The Rhoetosaurus remains from Roma, further to the south east, were found in much harder sandstone, dating to the Middle Jurassic.
The large ornithopod Muttaburrasaurus langdoni and the ankylosaur Minmi paravertebra, probably the two most complete dinosaurs discovered in Australia, were both found in this area. Australia's only known sauropods, Rhoetosaurus brownei, Austrosaurus mckillopi, Diamantinasaurus matildae, Wintonotitan wattsi, and several yet-to-be-described animals, were also discovered in this region (Rhoetosaurus a bit further to the south east, but still in Queensland). The megaraptoran theropod Australovenator wintonensis was described in 2009.
Winton is famous for its well preserved dinosaur trackway at Lark Quarry. They seem to show the result of a dinosaur "stampede", consisting of hundreds of footprints from small and medium sized carnivores and herbivores, with the footprints of a single large carnivore, perhaps the cause of the stampede.
The Opal Fields
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Dinosaur remains have been found in the opal fields of South Australia and New South Wales. The coelurosaur Kakuru kujani is represented by a single mostly complete tibia (lower leg bone) from Andamooka in South Australia. The word "Kakuru" means "rainbow serpent" in the local aboriginal language, probably because the opalised fossil sparkles with many colours. Other South Australian material includes a juvenile hypsilophodontid vertebra from Andemooka, and an isolated ankle bone of a large ornithopod, perhaps something like Muttaburrasaurus, from Coober Pedy.
Fulgurotherium australe is a hypsilophodontid known from the opal fields of Lightning Ridge in New South Wales. The name "Fulgurotherium" means "lightning beast" after the area it was discovered in. Various isolated pieces of large ornithopod bone have also been found, some of which have been tentatively assigned to Muttaburrasaurus. The remains of Rapator, a single bone from the hand, are also known from Lightning Ridge.
Some of the best preserved marine reptile remains have also come from the various opal fields around the country, although of course these are not dinosaurs.
Western Australian sites
Western Australia has yielded only meagre dinosaur remains. A single partial humerous found near Giralia dates to the Late Cretaceous, and appears to be from a theropod. It was once suggested it could have been from a dromaeosaur, although it is too badly preserved to be certain. It has also suggested that it may be from a therizinosaur. Other isolated remains include a mid caudal vertebra dating to the Early Cretaceous, and a toe bone from the Late Cretaceous, both of which show some similarity to allosaurids.
In 1998 a distal tibia of a Jurassic theropod, called Ozraptor, was described, the first Australian Jurassic theropod to be discovered, and the first named dinosaur taxon from Western Australia.
Western Australia is better known for its footprint sites, one near Broome that has a wide range of dinosaur footprint types from small and large bipeds to huge sauropods, as well as what may have been a stegosaur hand print (since stolen from the site). Other sites were discovered along the coast in 1997, although their exact locations have not been disclosed.