Here we describe a mosasaurid from the upper Maastrichtian Quiriquina Formation near the town of Cocholgik about 30 km north of Concepcion, central Chile. The specimen comprises a concretion preserving the rostral part of a pair of mandibular rami. The bulbous base of the teeth allows referral to cf. Plotosaurus sp. This is southernmost record of this piscivorous and pelagic taxon. The southern dispersal of mosasaurs during the late Maastrichtian may not only have depended from warm south-bound Equatorial currents but mainly from the nutrient-rich oceanic regime along an upwelling zone of cold abyssal water that mixed with the warm surface water, resulting in an enormous primary production. Apparently mosasaur dispersal depended more on food than on suitable temperatures or currents. (C) 2015 Elsevier Ltd. All rights reserved.