Australia isn’t well-known for exceptional dinosaur fossils. Even though the continent contains some spectacular tracksites, such as the “Dinosaur Stampede,” many of the dinosaurs discovered in Australia over the past few years are only known from scraps. Among the exceptions are a trio of dinosaurs first described in 2009 from remains found in Queensland–a pair of sauropods and a theropod nicknamed “Banjo.” These roughly 110-million-year-old dinosaurs were all represented by partial skeletons, and there is even more material from these animals than was originally detailed. Paleontologists are continuing to prepare and study dinosaur bones from the site. The latest tidbit from the site concerns Banjo’s arm.
Banjo’s official name is Australovenator wintonensis. This roughly 20-foot-long carnivore belonged to a group of Allosaurus-like theropods called Neovenatorids. Judging by the anatomy of their skulls and forelimbs, these dinosaurs used both jaws and claws to bring down prey, and a recent paper by Matt White and colleagues provides a detailed look at the formidable arms of Australovenator.
As mentioned by White and co-authors, the new bones include elements from the dinosaur’s upper arm, lower arm and hand. Together, these bones give paleontologists a near-complete view of Banjo’s arms. Like its close relatives, Australovenator had a stout thumb tipped with a large claw, while the other two fingers were more slender and bore smaller curved weapons. From a more detailed perspective, the paleontologists also suggest that the arms of Australovenator and its close relatives might be useful in parsing the evolutionary relationships among these predatory dinosaurs.
Exactly how Australovenator used its arms is unknown. White and collaborators mention that a biomechanical analysis of the dinosaur’s arm is underway, and that study will hopefully outline how Banjo and other Neovenatorids combined teeth and claws in their hunting strategy. The new paper is primarily a detailed inventory of Banjo’s hand, and even though behavioral interpretations are sexy–it’s hard to look at theropod claws and not wonder about the damage they could inflict–we need papers that fully reconstruct a dinosaur’s anatomy first. Once we know what’s we’re looking at, then we can investigate the amazing things dinosaurs were capable of.
White MA, Cook AG, Hocknull SA, Sloan T, Sinapius GH & Elliott DA (2012). New Forearm Elements Discovered of Holotype Specimen Australovenator wintonensis from Winton, Queensland, Australia. PloS One, 7 (6) PMID: 22761772