A new trackway possibly made by a trotting theropod at the Las Hoyas fossil site (Early Cretaceous, Cuenca Province, Spain): Identification, bio-dynamics, and palaeoenvironmental implications

Dinosaur footprints have recently been identified at the Las Hoyas fossil site, renewing interest in its trace fossils as aids in the interpretation of the area's palaeoenvironment and palaeocommunity. The varied tetrapod print morphologies found seem to have been influenced by the contemporaneous presence of microbial mats. This paper updates the information on tetrapod traces at the site and describes a new dinosaur trackway containing four tridactyl footprints. Although the trackway is not particularly well-preserved, the morphology of the toe marks, the heel surface, and the general morphology of the prints strongly suggest they were produced by a theropod dinosaur of medium size. Further, the ratio between the stride length and the deduced hip height suggest the trackmaker was trotting. Interestingly, the footprints are very similar in size to the pes of Concavenator, a carcharodontosaurid dinosaur known from skeletal material at the same locality. This new ichnological evidence reveals tetrapod prints to be more abundant toward the top of the siteʼs stratigraphic succession. This suggests that, over time, the ecosystem evolved toward more frequent dry periods the dinosaurs present became able to walk in areas with shallow water and big dinosaurs walked across the ponding zone of Las Hoyas. J.J. Moratalla. Instituto Geológico y Minero de España (Igme), Museo Geominero, Ríos Rosas 23, 28003 Madrid, Spain. [email protected] J. Marugán-Lobón. Unidad de Paleontología, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain and Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, CA, USA. [email protected] H. Martín-Abad. Jurassica Museum, Route de Fontenais 21, 2900 Porrentruy, Switzerland. [email protected] and Department of Geosciences, University of Fribourg, Chemin du Musée 6, 1700 Fribourg, Switzerland E. Cuesta. Unidad de Paleontología, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain. [email protected] Moratalla, J.J., Marugán-Lobón, J., Martín-Abad, H., Cuesta, E. and Buscalioni, A.D. 2017. A new trackway possibly made by a trotting theropod at the Las Hoyas fossil site (Early Cretaceous, Cuenca Province, Spain): Identification, bio-dynamics, and palaeoenvironmental implications. Palaeontologia Electronica 20.3.59A: 1-14. https://doi.org/10.26879/770 palaeo-electronica.org/content/2017/2073-theropod-trackway-at-las-hoyas Copyright: November 2017 Palaeontological Association. This is an open access article distributed under the terms of Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0), which permits users to copy and redistribute the material in any medium or format, provided it is not used for commercial purposes and the original author and source are credited, with indications if any changes are made. creativecommons.org/licenses/by-nc-sa/4.0/ MORATALLA ET AL.: THEROPOD TRACKWAY AT LAS HOYAS A.D. Buscalioni. Unidad de Paleontología, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain. [email protected].