Richard J. ButlerA, Laura B. PorroB, and David B. NormanB
A. Department of Palaeontology, The Natural History Museum, Cromwell Road, London, SW7 5BD, United Kingdom, E-mail: R.Butler@nhm.ac.uk, B. Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, United Kingdom, E-mail: lbp24@esc.cam.ac.uk, E-mail: dn102@esc.cam.ac.uk
Heterodontosaurids are an enigmatic group of primitive ornithischian dinosaurs best known from the Early Jurassic of southern Africa. Because fossil material is rare and often poorly preserved, the taxonomy, systematics, and palaeobiology of this clade are controversial. Here we describe a new partial skull of a juvenile Heterodontosaurus tucki from the 'Stormberg' of South Africa. This skull provides new information on the cranial anatomy of this taxon as well as insights into cranial ontogeny, sexual dimorphism and tooth replacement in heterodontosaurids. Few ontogenetic changes in dental morphology occur in Heterodontosaurus, supporting previous suggestions that tooth characters are informative for species-level taxonomy in heterodontosaurids. Furthermore, the presence of well-developed caniniform teeth in the juvenile specimen does not support the hypothesis that these represent secondary sexual characteristics in heterodontosaurids. Computed tomography reveals that replacement teeth are absent in both juvenile and adult specimens of Heterodontosaurus; however, the difference in the absolute size of the teeth between the juvenile and adult specimens demonstrates that replacement must have occurred during ontogeny.
Link above! Heterodontosaurs are one clade I find really fascinating simply because they seem so different than the other dinos.
They are quite strange. This new paper is interesting for several reasons, among them the idea that juveniles didn't look much different than adults, which weakens the link between heterodontosaurs and ceratopsids.
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