Nueva evidencia icnológica de dinosaurios en el Cretácico inferior de La Rioja (España)

Abstract

Three new Early Cretaceous (Hauterivian) dinosaur footprints outcrops are reported from La Rioja: Valdeté, La Magdalena (townsbip of Préjano) and Muro de Aguas. The morphology and size of the footprints suggest that the track-makers are three different iguanodontids at least. The footprints from La Magdalena were printed by a graviportal ornithopod osteologically unknown. That morphotype shows a maximun development of graviportality within the biped dinosaurs (omithopods or theropods). Within omithopod dinosaurs graviportality is a derived structural state from a relatively slender, tridactyl, mesaxonic formo Respect to the estimation of speed of the track-makers, the height of the limb (b) has been calculated by means of an statistical analysis within the osteological material of several iguanodontids. The speed values are the common ones reported within medium and great sized ornithopods. Ten dinosaur footprint morphotypes, at least, have been reported from La Rioja Baja and the Nord area of Soria, up to now (four medium-great sized ornithopods, one small sized ornithopod, two theropods, one coelurosaur and two sauropods).