The Ediacaran-Cambrian Radiation of Animals within the Villuercas-Ibores-Jara UNESCO Global Geopark, Spain

Across the Ediacaran to Cambrian transition, some 541 Ma, the Earth’s biosphere changed from one dominated by microbial organisms to one where multicellular organisms, including animals, rose to importance. Within a few tens of millions of years into the Cambrian Period an array of animal groups appeared, some extinct and others ancestral to modern groups, the Cambrian “explosion”. Two key elements were the appearance of biomineralized hard parts and the rise of animal disturbance of the sea floor (bioturbation), which continued into the great Ordovician biodiversification event (GOBE). These events are well documented in the Villuercas-Ibores-Jara UNESCO Global Geopark (UGG) by trace fossils, carbonaceous compression fossils and fossils of some of the earliest skeletonized animals record. Simple to more complex trace fossils are evidence of the “Cambrian substrate revolution”. Among carbonaceous compressions, sabelliditids provide evidence of tubular animals and vendotaenids possibly of algae. In addition, Villuercas-Ibores-Jara is the only UNESCO Global Geopark with Cloudina, the first described and best-known of the pioneering organisms in the acquisition of skeletons. Geosites, geological itineraries and interpretation centers in the geopark show visitors these exceptional fossils, including the holotype of Cloudina carinata.