Impact of Sauropod Dinosaurs on Lagoonal Substrates in the Broome Sandstone (Lower Cretaceous), Western Australia

Existing knowledge of the tracks left by sauropod dinosaurs (loosely ‘brontosaurs’) is essentially two-dimensional, derived mainly from footprints exposed on bedding planes, but examples in the Broome Sandstone (Early Cretaceous) of Western Australia provide a complementary three-dimensional picture showing the extent to which walking sauropods could deform the ground beneath their feet. The patterns of deformation created by sauropods traversing thinly-stratified lagoonal deposits of the Broome Sandstone are unprecedented in their extent and structural complexity. The stacks of transmitted reliefs (underprints or ghost prints) beneath individual footfalls are nested into a hierarchy of deeper and more inclusive basins and troughs which eventually attain the size of minor tectonic features. Ultimately the sauropod track-makers deformed the substrate to such an extent that they remodelled the topography of the landscape they inhabited. Such patterns of substrate deformation are revealed by investigating fragmentary and eroded footprints, not by the conventional search for pristine footprints on intact bedding planes. For that reason it is not known whether similar patterns of substrate deformation might occur at sauropod track-sites elsewhere in the world

History and nomenclature of the theropod dinosaur tracks Bueckeburgichnus and Megalosauripus

The most recent account of Bueckeburgichnus maximus Kuhn 1958, a distinctive theropod dinosaur track from the Lower Cretaceous of Germany, is shown to be based on a referred specimen mistakenly identified as the holotype and the correct name of this taxon is deemed to be Megalosauripus maximus (Kuhn 1958). This minor revision has important consequences for nomenclature of the many European, Asian, North American and Australian dinosaur tracks attributed to megalosaurian theropods. Many of those tracks were named Megalosauripus, but that name has a confusing multiplicity of meanings and it should be restricted to the highly characteristic dinosaur track formerly identified as Bueckeburgichnus. Other tracks named "Megalosauripus”; (in its several other senses) will require new nomenclature, despite their extensive and repeated revision since 1996. It is recommended that future revision should adopt conventions of the International Code of Zoological Nomenclature. Although previous revisions expressed an intention to adhere to those conventions, these were not put into practice, with the unfortunate result of multiplying the problems that surround the nomenclature of megalosaur tracks. Introduction of the name Megalosauripus maximus (Kuhn 1958) eliminates those burgeoning problems and permits the introduction of new and objective nomenclature for presumed megalosaur tracks

Extramorphological features of sauropod dinosaur tracks in the Uhangri Formation (Cretaceous), Korea

Sauropod footprints in the Uhangri Formation (Cretaceous) of Korea exhibit an unusual pattern of morphology, with the interior of each print partitioned into a series of pockets by conspicuous radial crests. The crests are evidently extramorphological features and have been interpreted as upwellings of sediment extruded through the floor of the footprint following its fracture by impact of the trackmaker's foot. That explanation entails some inconsistencies, and an alternative explanation is proposed here. The alternative explanation envisages delamination of a superficial sheet of sediment that was lifted into a canopy, which subsequently collapsed in radiating folds. The superficial sheet of sediment might have been lifted by either or both of two mechanisms-by adhering to the underside of the trackmaker's foot or by being forced upward into a blister-like dome by the backflow of water previously displaced by impact of the trackmaker's foot. These alternative explanations draw attention to minor morphological features that were previously unexplained