Riversleigh

= Riversleigh fossil site in North Qld has had an enormous influence on palaeontology and is now a World Heritage site. This is because it is one of the world's most diverse fossil records-it documents a continuous history of changing climate, habitat and its associated fauna and extinctions as rainforest retreated and the continent dried up. The species that lived there 25mya was dominated by ancestral marsupials, such as wombats, koalas, moles, bandicoots, kangaroos, dasyrids, marsupial lions and possums. Other species included monotremes, birds and reptiles.The Riversleigh site also acts as an indicator for the future of some of our fragile or endangered fauna. Six species of thylacine were discovered at Riversleigh but fewer species were evident with advancing time. This record mimics a decline in diversity and distribution in other areas. =

=__To describe Australian fossils and where these fossils are found.__= Three fossils that are found at Riversleigh are the Riversleigh Platypus (Obdurodon dicksoni), Riversleigh Leaf-nosed Bat (Brachipposideros nooraleebus) and the Dickson's Thylacine (Nimbacinus dicksoni). The Riversleigh Platypus is similar to the present day platypus. A few teeth were discovered followed by a spectacular find of an almost complete skull of a fossil platypus about 15 to 20 million years old. The skull of the Riversleigh platypus is one of the most perfect fossils ever preserved. It is about 25% longer than one of a modern day Platypus. Fossil records of the Riversleigh platypus show that they had large teeth and would have lived in freshwater pools surrounded by rainforest. =   =  The Riversleigh Leaf-nosed Bat lived in limestone caves and ventured out into the forest to hunt insects. . Thousands of fragile fossils of // the // species have been collected from the Riversleigh limestone and many of these bat sites represent old limestone cave deposits. The fine preservation of many of the specimens suggests that fossilization was rapid and that it occurred at the roosting site. The closest living relative of the Riversleigh Leaf-nosed Bat is its descendant the Orange Horseshoe Bat (Rhinonicterus aurantius). This is a rare bat that still lives in caves in the Riversleigh region.

Dickon's Thylacine was a predator that ate small and medium-sized mammals, reptiles and birds. It was not a fast runner; however it would perform long chases to exhaust its prey. Fossil records found upper and lower jaw fragments and isolated teeth. A complete skull and lower jaw was found in 1996 together with a near complete skeleton of the thylacine.

=__To explain how fossils contribute to the development of understanding about the__= = = = = = = = = = = = = = = = = = = = = = = =__To identify similarities and differences between current and extinct Australian life forms.__= = Riversleigh Platypus (Obdurodon dicksoni) = = The Riversleigh Platypus is fairly similar in appearance when compared to today’s platypus, however it was slightly larger and had a much larger bill and large teeth (which is a contrast from the modern platypus who has no teeth). The Riversleigh Platypus is approximately 60cm in length. Fossil teeth of this monotreme were found in 1984 in Riversleigh and then a skull in 1985 which was seen as more generalized and about 25% longer than the modern platypus.A baby Riversleigh Platypus would have teeth and lose them when they were young before becoming an adult and using the horny pads found inside the mouth to break up the food. It is also similar to the modern platypus because it also had electric sensors in its bill which allowed it to find its underwater prey and this would consist of larvae, yabbies and living in freshwater which are what they do today. = = = = = = = = Riversleigh Leaf-nosed Bat = = This animal lived 24-16 million years ago and had a wingspan of 15 cm. This animal lived in limestone caves and ventured out into the forest to hunt for insects. It is very similar to the Orange Horseshoe Bat which is a rare bat that still lives in the caves of Riversleigh. Close fossil relatives can be found as far away as France, Madagascar and Vietnam therefore supporting the theory that all animals lived on one continent and then as the tectonic plates began to move animals changed and adapted to their own environments. = = Dickson's Thylacine (Nimbacinus Dicksoni) = = = = = = = = = = = = Tingamaeea Swamp Crocodile = The Tingamarra Swamp Crocodile lived approximately 55 million years ago and its skull was found at Riversleigh. It is very similar to the modern day crocodile having a diet of small vertebrae animals, small mammals, fish and turtles and lived in swamp areas in Queensland, It was also similar in body structure with reptilian scales, a long and strong tail with sharp carnivorous teeth however a difference between these two life forms is that the Tingamarra Swamp Crocodile was only approximately 1.5m in length which is much smaller than the everyday slat and freshwater crocodiles found in Australia. = =

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