Intra-trackway morphological variations due to substrate consistency: the El Frontal dinosaur tracksite (Lower Cretaceous, Spain).

An ichnological and sedimentological study of the El Frontal dinosaur tracksite (Early Cretaceous, Cameros basin, Soria, Spain) highlights the pronounced intra-trackway variation found in track morphologies of four theropod trackways. Photogrammetric 3D digital models revealed various and distinct intra-trackway morphotypes, which reflect changes in footprint parameters such as the pace length, the track length, depth, and height of displacement rims. Sedimentological analyses suggest that the original substrate was non-homogenous due to lateral changes in adjoining microfacies. Multidata analyses indicate that morphological differences in these deep and shallow tracks represent a part of a continuum of track morphologies and geometries produced by a gradient of substrate consistencies across the site. This implies that the large range of track morphologies at this site resulted from similar trackmakers crossing variable facies. The trackways at the El Frontal site present an exemplary case of how track morphology, and consequently potential ichnotaxa, can vary, even when produced by a single trackmaker

A standard protocol for documenting modern and fossil ichnological data

The collection and dissemination of vertebrate ichnological data is struggling to keep up with techniques that are becoming common place in the wider palaeontological field. A standard protocol is required in order to ensure that data is recorded, presented, and archived in a manner that will be useful both to contemporary researchers, and to future generations. Primarily, our aim is to make the 3D capture of ichnological data standard practice, and to provide guidance on how such 3D data can be communicated effectively (both via the literature and other means), and archived openly and in perpetuity. We recommend capture of 3D data, and the presentation of said data in the form of photographs, false-colour images, and interpretive drawings. Raw data (3D models of traces) should always be provided in a form usable by other researchers, i.e. in an open format. If adopted by the field as a whole, the result will be a more robust and uniform literature, supplemented by unparalleled availability of datasets for future workers

The tracks of giant theropods (<i>Jurabrontes curtedulensis</i> ichnogen. & ichnosp. nov.) from the Late Jurassic of NW Switzerland: palaeoecological & palaeogeographical implications

<p><i>Jurabrontes curtedulensis</i>, a new ichnogenus and species of Late Jurassic giant theropod dinosaur track is described based on very well-preserved and morphologically-distinct tracks, all carefully excavated along federal highway A16 (Canton Jura, NW Switzerland). All trackways were systematically documented including parameter measurements, descriptions, outline drawings, orthophotos and laserscans. <i>Jurabrontes</i> is characterised by sub-equal track length and width, a small anterior triangle, weak mesaxony, three blunt digits (dII-III-IV) with pronounced (sub)triangular claw marks, a rounded heel, and clear phalangeal pad impressions. The combination of features of <i>Jurabrontes</i> is typical for a theropod (and not ornithopod) trackmaker. <i>Jurabrontes</i> is compared to other similar ichnotaxa and unnamed tracks of large theropods from the Early Jurassic to Late Cretaceous, from which it is clearly different. The sheer size of the largest tracks, that are amongst the largest worldwide and of similar size to <i>Tyrannosauripus</i> from the Late Cretaceous, suggests a ‘megalosaurid’ or large allosaurid theropod as a trackmaker. The presence of such large theropod tracks in tidal-flat deposits of the Jura carbonate platform and associated with small to large sauropod tracks has important palaeoecological implications for the dinosaur community and for palaeoenvironmental and palaeogeographical reconstructions.</p> <p><i>Jurabrontes</i> - <a href="http://urn:lsid:zoobank.org:act:B482D2AF-637A-4B2D-8B0B-FEAD54CA2A26" target="_blank">urn:lsid:zoobank.org:act:B482D2AF-637A-4B2D-8B0B-FEAD54CA2A26</a></p> <p><i>J. curtedulensis</i>- <a href="http://urn:lsid:zoobank.org:act:30D45944-5A2B-45E1-89B9-20298E475D51" target="_blank">urn:lsid:zoobank.org:act:30D45944-5A2B-45E1-89B9-20298E475D51</a></p

The first megatheropod tracks from the Lower Jurassic upper Elliot Formation, Karoo Basin, Lesotho

A palaeosurface with one megatheropod trackway and several theropod tracks and trackways from the Lower Jurassic upper Elliot Formation (Stormberg Group, Karoo Supergroup) in western Lesotho is described. The majority of the theropod tracks are referable to either Eubrontes or Kayentapus based on their morphological characteristics. The larger megatheropod tracks are 57 cm long and have no Southern Hemisphere equivalent. Morphologically, they are more similar to the Early Jurassic Kayentapus, as well as the much younger Upper Cretaceous ichnogenus Irenesauripus, than to other contemporaneous ichnogenera in southern Africa. Herein they have been placed within the ichnogenus Kayentapus and described as a new ichnospecies (Kayentapus ambrokholohali). The tracks are preserved on ripple marked, very fine-grained sandstone of the Lower Jurassic upper Elliot Formation, and thus were made after the end-Triassic mass extinction event (ETE). This new megatheropod trackway site marks the first occurrence of very large carnivorous dinosaurs (estimated body length >8-9 meters) in the Early Jurassic of southern Gondwana, an evolutionary strategy that was repeatedly pursued and amplified in the following ~135 million years, until the next major biotic crisis at the end-Cretaceous