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Description
Theropod dinosaurs were seemingly quite rare components of the Late Oligocene Etadunna Formation. Aside from some isolated teeth belonging to an unnamed Megaraptoran that measured in the 6m range, all other Theropods recovered from the region were rather modestly sized animals. Interestingly, an almost complete lower jaw of a Noasaurian Ceratosaur has been uncovered here. Highly fragmentary Cretaceous fossil remains had indicated the presence of this odd group of Theropods in Australia, although the Edatunna jawbone provided definitive proof. Named Diyarirynchus, this genus was a toothy carnivore about 2.5m long and would have resembled animals such as Vespersaurus and Masiakasaurus. This animal is the most basal known member of the endemic Australian family Xerycosauridae, a group that persists into modern times in the arid and Semi-arid regions of the continent. The jaws of Diyarirhynchus were relatively robust, almost Abelisaur-like in certain respects, which would have allowed this animal to tackle many of the Ornithischians with which it shared its environment. This also enabled the Noasaur to avoid competition with other small Theropods, although post-cranial remains of this genus are entirely unknown.

Another surprising discovery was the presence of a unique Paravian family formerly known only from Antarctica. Imperobatorids, first represented by the poorly understood Late Cretaceous genus Imperobator, are carnivorous Theropods that rank among the most basal members of Paraves. Lacking the distinctive sickle claws of Early Avialans, Troodontans and Dromaeosaurs, these animals inhabited a similar role to these groups in the land down under. A notable sub-family are the Erythroraptorines, a group of modest and predatory forms that superficially resembled the Troodontids of the Late Cretaceous. Surviving into modern times as nocturnal hunters of small mammals, lizards and snakes, Erythroraptorines first appear in the fossil record during the Late Oligocene but diverged significantly earlier, probably during the Early Eocene. The oldest known example of the group is Muloorinasaurus from Edatunna, being a slender, leggy 2m long carnivore. Possessing a narrow, elongated snout equipped with small sharp teeth, M. inexpectatus is known from several partial specimens.

Unlike at the near contemporary Oligocene deposits at Riversleigh, avian fossil material is incredibly rare at the Lake Ngapakaldi to Lake Palankarinna Fossil Area. Only a single genus of Enantiornithine has been described and named, being a member of the bizarre clade Ozopterygiformes. This was the chicken-sized and rail-like Ozcrex, a wading forager belonging to the largely terrestrial Pseudodromornithoidea clade; a lineage that would diversify during the aridification of Australia during the second half of the Miocene.

Description
Theropod dinosaurs were seemingly quite rare components of the Late Oligocene Etadunna Formation. Aside from some isolated teeth belonging to an unnamed Megaraptoran that measured in the 6m range, all other Theropods recovered from the region were rather modestly sized animals. Interestingly, an almost complete lower jaw of a Noasaurian Ceratosaur has been uncovered here. Highly fragmentary Cretaceous fossil remains had indicated the presence of this odd group of Theropods in Australia, although the Edatunna jawbone provided definitive proof. Named Diyarirynchus, this genus was a toothy carnivore about 2.5m long and would have resembled animals such as Vespersaurus and Masiakasaurus. This animal is the most basal known member of the endemic Australian family Xerycosauridae, a group that persists into modern times in the arid and Semi-arid regions of the continent. The jaws of Diyarirhynchus were relatively robust, almost Abelisaur-like in certain respects, which would have allowed this animal to tackle many of the Ornithischians with which it shared its environment. This also enabled the Noasaur to avoid competition with other small Theropods, although post-cranial remains of this genus are entirely unknown.

Another surprising discovery was the presence of a unique Paravian family formerly known only from Antarctica. Imperobatorids, first represented by the poorly understood Late Cretaceous genus Imperobator, are carnivorous Theropods that rank among the most basal members of Paraves. Lacking the distinctive sickle claws of Early Avialans, Troodontans and Dromaeosaurs, these animals inhabited a similar role to these groups in the land down under. A notable sub-family are the Erythroraptorines, a group of modest and predatory forms that superficially resembled the Troodontids of the Late Cretaceous. Surviving into modern times as nocturnal hunters of small mammals, lizards and snakes, Erythroraptorines first appear in the fossil record during the Late Oligocene but diverged significantly earlier, probably during the Early Eocene. The oldest known example of the group is Muloorinasaurus from Edatunna, being a slender, leggy 2m long carnivore. Possessing a narrow, elongated snout equipped with small sharp teeth, M. inexpectatus is known from several partial specimens.

Unlike at the near contemporary Oligocene deposits at Riversleigh, avian fossil material is incredibly rare at the Lake Ngapakaldi to Lake Palankarinna Fossil Area. Only a single genus of Enantiornithine has been described and named, being a member of the bizarre clade Ozopterygiformes. This was the chicken-sized and rail-like Ozcrex, a wading forager belonging to the largely terrestrial Pseudodromornithoidea clade; a lineage that would diversify during the aridification of Australia during the second half of the Miocene.