An overview of Upper Cretaceous dinosaur tracks and other trace fossils from the Barreales lake area, Neuquén Province, Patagonia, Argentina

Abstract

Upper Cretaceous (Turonian–Santonian) tracksites at Barreales Lake, Neuquén Province, Argentina are described. Tracksites studied for the last 20 years on the northern and northeastern coasts of the lake mainly contain theropod and sauropod tracks preserved as either natural molds, concave epireliefs, concave hyporeliefs, or convex hyporeliefs. Sauropod tracks and trackways represent taxa that exhibited wide-gauge locomotor styles. Based on their morphology and evidence from body fossils, they are interpreted as having been produced by titanosaurs. Theropod tracks are represented by tridactyl prints with claw impressions. Some of the theropod tracks are inferred as having been made by megaraptorids. The dinosaur track record of the Barreales Lake region spans several formations: the Portezuelo Formation yielded theropod tracks at the Baal, Punta Motorhome, Aguas Claras, and South Loma de la Lata sites; the Plottier Formation preserves sauropod and ornithopod tracks at the Proyecto Dino and Middle Loma de la Lata sites, respectively; and the Bajo de la Carpa Formation yielded sauropod and theropod tracks at the Querubín site. Here we describe all these dinosaur tracksites and make inferences regarding their paleoenvironments. A brief description of some invertebrate traces from the Querubín tracksite is also provided. The description of these tracks and trackways adds to knowledge of Late Cretaceous continental paleoecosystems of southern South America.