Name: Qantassaurus intrepidus
Etymology: After the Australian airline Qantas for their support of dinosaur research at the time of discovery (1996), and the Greek 'saurus' (masculine, lizard); and the Latin 'intrepidus' (unshaken, undaunted, brave, bold)
Distribution: Early Cretaceous (Aptian) of south-eastern Australia
Type Specimen: Left dentary (jaw), almost complete
Estimated size: ~2 m in length
First described by: Rich and Vickers-Rich, 1999.
Image courtesy of Wikipedia
For example, based on the presence of a primary ridge on the inner surface of the teeth (see images below), Rich et al. (1999) described Qantassaurus intrepidus as a hypsilophodontid, a type of ornithopod (bipedal, unarmoured, herbivorous). But closer examination by other researchers found that many types of ornithopods, not just hypsilophodontidae, have primary ridges on their teeth (Agnolin et al., 2010). They also identified secondary ridges next to the primary ridges, and with a tooth count of less than 12, decided that Q. intrepidus was not a hypsilophodontid, but a basal ornithopod (Agnolin et al., 2010).
Bottom photo: close-up of jaw bone in medial view, showing the primary ridge on the lingual surface (Correction: after a kind tip-off from an expert, have replaced original image which showed secondary/subsidiary ridge on labial surface incorrectly marked as 'primary ridge').
Images courtesy of Museum Victoria (Photo: Benjamin Healley)
Rich, T. H., Vickers-Rich, P. 1999. The Hypsilophodontidae from southeastern Australia. Proceedings of the Second Gondwanan Dinosaur Symposium, National Science Museum Monographs 15:167-180