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Description
Dinosaur fossils were quite common at the Late Oligocene Etadunna sites, with Ornithischians being the most numerous by far. At least 9 genera were present and came in a wide range of sizes and ecological specializations, of which three can be seen in the image above. In the foreground stands the small herbivorous generalist Barretocursor, a member of the Elasmarian lineage Tingacursoroidea. An ancient branch that first appears in the fossil record at the Early Eocene Murgon site, Tingacursoroids maintain a modest presence in modern Australia as forest dwelling herbivores/omnivores native to Tasmania and the eastern coastline of the continent. Their teeth are rather unspecialized, with living species regularly consuming insects, worms and even carrion in addition to plant matter. It is assumed that Barretocursor was similar, being a 1.5m generalist herbivore/omnivore that utilized a rapid turn of speed to escape from predators, including Diyarirhynchus and Staurikosuchian Notosuchians. The large striped animal at the rear of the image is another Elasmarian, albeit a member of a different lineage: the Sclerosauriform Eyredontosaurus. The Sclerosauriformes are an unusual bunch of unstable phylogenetic placement. It has been suggested that these animals might have been close relatives of Quantassaurus but this remains controversial. A basal generalized family dwelt at Edatunna and Riversleigh during the Late Oligocene: the Walpirisaurids. Eyredontosaurus was the largest Elasmarian known from the region, being a somewhat stocky browser up to 3.5m long. Animals such as this would have been ideal prey for the large Notosuchian Gojirasuchus, the apex predator at Etadunna. Sclerosauriforms were more common at Riversleigh, with some forms even adapting to a semi-arboreal existence. The red-headed stocky animal on the right, Strzeleckignathus, was not an Elasmarian but a member of a more basal Ornithopod lineage: the Oceaniadontians. This clade appears to have been close relatives of the Cretaceous Weewarasaurus and were native to both Australia and Zeelandia. The Australian clade have been named Australornithopoda and would go on to produce a variety of both cursorial browsers and bulky, vaguely Ceratopsian-like forms. Two genera were present in the Edatunna Formation, with these being the generalized, basal Ngapakaldisaurus (a 2.5m lightly built genus) and the more robust and durophagous Strzeleckignathus. The latter probably fed on tough low growing plant material, including cycads, bark and rotting logs. During the aridification of Australia during the Miocene, relatives of Strzeleckignathus would readily adapt, growing larger and producing massive forms by the Pleistocene.

Description
Dinosaur fossils were quite common at the Late Oligocene Etadunna sites, with Ornithischians being the most numerous by far. At least 9 genera were present and came in a wide range of sizes and ecological specializations, of which three can be seen in the image above. In the foreground stands the small herbivorous generalist Barretocursor, a member of the Elasmarian lineage Tingacursoroidea. An ancient branch that first appears in the fossil record at the Early Eocene Murgon site, Tingacursoroids maintain a modest presence in modern Australia as forest dwelling herbivores/omnivores native to Tasmania and the eastern coastline of the continent. Their teeth are rather unspecialized, with living species regularly consuming insects, worms and even carrion in addition to plant matter. It is assumed that Barretocursor was similar, being a 1.5m generalist herbivore/omnivore that utilized a rapid turn of speed to escape from predators, including Diyarirhynchus and Staurikosuchian Notosuchians. The large striped animal at the rear of the image is another Elasmarian, albeit a member of a different lineage: the Sclerosauriform Eyredontosaurus. The Sclerosauriformes are an unusual bunch of unstable phylogenetic placement. It has been suggested that these animals might have been close relatives of Quantassaurus but this remains controversial. A basal generalized family dwelt at Edatunna and Riversleigh during the Late Oligocene: the Walpirisaurids. Eyredontosaurus was the largest Elasmarian known from the region, being a somewhat stocky browser up to 3.5m long. Animals such as this would have been ideal prey for the large Notosuchian Gojirasuchus, the apex predator at Etadunna. Sclerosauriforms were more common at Riversleigh, with some forms even adapting to a semi-arboreal existence. The red-headed stocky animal on the right, Strzeleckignathus, was not an Elasmarian but a member of a more basal Ornithopod lineage: the Oceaniadontians. This clade appears to have been close relatives of the Cretaceous Weewarasaurus and were native to both Australia and Zeelandia. The Australian clade have been named Australornithopoda and would go on to produce a variety of both cursorial browsers and bulky, vaguely Ceratopsian-like forms. Two genera were present in the Edatunna Formation, with these being the generalized, basal Ngapakaldisaurus (a 2.5m lightly built genus) and the more robust and durophagous Strzeleckignathus. The latter probably fed on tough low growing plant material, including cycads, bark and rotting logs. During the aridification of Australia during the Miocene, relatives of Strzeleckignathus would readily adapt, growing larger and producing massive forms by the Pleistocene.