Turtle and pterosaur tracks from the Los Cayos Dinosaur Tracksite, Cameros Basin (Cornago, La Rioja, Spain): tracking the Lower Cretaceous bio-diversity

Abstract

New fossil turtle and pterosaurian tracks have been found at the Los Cayos locality (Cornago township, La Rioja province, Spain). The Los Cayos tracksite is situated in the Cameros Basin, ant it is included in the Enciso Group, which is late Barremian-Early Aptian in age (Lower Cretaceous). The turtle tracks are formed by parallel isolated digit impressions. Digits show acuminate distal ends and relatively blunt proximal margins. Most of the tracks show three digits, and only two of them are pentadactyl. No trackways can be observed but only different track alignments suggesting some kind of direction of movement. Two track-bearing layers have yielded 5 pterosaur manus prints. No pes footprints or trackways have been discovered at these outcrops yet. These prints are tridactyl, with digit I, the shortest, and III, the longest. The angles between the digits are variable: angle I-II is significantly bigger than between II-III. These tracks from Los Cayos were the first discovery of pterosaur tracks in the Enciso Group.