Never put all the eggs in the same basket: Fossil record of enteroliths in the quaternary of South America

Three strange fossils from quaternary deposits in Uruguay are reported. One of them was recently described as belonging to a bird's egg, but both the internal structures of this and the other two materials, as well as their phosphorus-rich chemical compositions, show that we are in the presence of something much rarer and almost unprecedented for the world fossil record: mammalian intestinal stones, more precisely called “enteroliths”. The scarce veterinary bibliography and the only previous paleontological reference related to this type of fossil suggests that the three specimens analyzed here were produced by terrestrial mammals during the late Pleistocene. •This work proves that a recently published fossil avian egg actually is a fossil entherolith.•Besides this contribution presents other entheroliths of very similar features.•These three fossils are related to some Pleistocene megamammal.