Muttaburrasaurus

Abstract: Disarticulated and incomplete remains from a new diminutive ornithopod are described. They come from the Cameros Basin in the north of Spain and were collected from the red clays of the Castrillo de la Reina Formation, ranging from Upper Barremian to Lower Aptian. The new ornithopod described here is slender and one of the smallest ever reported. An up-to-date phylogenetic analysis recovers this taxon as a basal iguanodontian. Its unique combination of characters makes it more derived than slender ornithopods like Hyphilophodon and Gasparinisaura, and bring very interesting insights into the basal iguanodontian phylogeny. Though possessing a minimum of three premaxillary teeth, this taxon also bears an extensor ilio-tibialis groove on the distal part of its femur. Moreover, its dentary and maxillary teeth are unique, remarkably similar to those regarded as having a “rhabdomorphan” affinity. This unknown taxon is suggested to be a stem taxon within Rhabdodontidae, a successful clade of basal iguanodonts from the Late Cretaceous of Europe. The Gondwanan ornithopods share the strongest affinities with this family, and we confirm Muttaburrasaurus as a sister taxon of the Rhabdodontidae within a newly defined clade, the Rhabdodontomorpha.

Abstract: Abstract Vectisaurus valdensis is considered to be the imperfectly preserved remains of juvenile Iguanodon . Based on juvenile material of Iguanodon recovered from Nehden (Federal Republic of Germany), Vectisaurus is most probably referrable to I. atherfieldensis . Ornithopod relationships have been evaluated by reference to the detailed recent systematic reviews of the Ornithischia. Results from this study suggest that the family Iguanodontidae is valid, if more restricted than previously argued; that Tenontosaurus tilletti is more closely related to hypsilophodontians than iguanodontians; and, that Probactrosaurus gobiensis is the sister-taxon of the Hadrosauridae. A revised cladogram of advanced ornithopod dinosaurs is proposed. Introduction In 1879, John Wittaker Hulke described the partial, associated skeleton of a small ornithopod that had been recovered from the Wealden Marls near Brixton (Brighstone) Chine (Isle of Wight, southern England). In the description of this material (Figs. 11.1, 11.2, 11.3), which included five dorsal vertebrae, an anterior caudal centrum, and a partial ilium, Hulke recognised several characters that merited the erection of a new genus and species distinct from the then known ornithopods from the Isle of Wight ( Hypsilophodon foxii and Iguanodon mantelli ). The principal characters by which Hulke distinguished this new taxon were: opisthocoelous dorsal centra with a nearly flat anterior articular surface, a heart-shaped posterior articular surface, a blunt ventral keel on the centra, and the quadrangular appearance of the anterior caudal centrum. Based on the preacetabular process of the ilium, Hulke referred this species to the family Iguanodontidae.

Abstract: Thulborn, R.A., 2013. Lark Quarry revisited: a critique of methods used to identify a large dinosaurian track-maker in the Winton Formation (Albian–Cenomanian), western Queensland, Australia. Alcheringa, http://dx.doi.org/10.1080/03115518.2013.748482 A remarkable assemblage of dinosaur tracks in the Winton Formation (Albian–Cenomanian) at Lark Quarry, a site in western Queensland, Australia, has long been regarded as evidence of a dinosaurian stampede. However, one recently published study has claimed that existing interpretation of Lark Quarry is incorrect because the largest track-maker at the site was misidentified and could not have played a pivotal role in precipitating a stampede. That recent study has identified the largest track-maker as an ornithopod (bipedal plant-eating dinosaur) similar or identical to Muttaburrasaurus and not, as formerly supposed, a theropod (predaceous dinosaur) resembling Allosaurus. Those iconoclastic claims are examined here and are shown to be groundless: they are based...