During the Pleistocene-Holocene transition at ~10.0 uncalibrated, or ~11.7 calibrated kya, the Americas were undoubtedly inhabited by humans from north to south ends. The groups living in that time had cultural and adaptive differences in terms of subsistence and technological pursuits. Particularly in the southern cone of South America, archaeological remains witnessed hunter-gatherers living at ~11.0-10.0 uncalibrated kya. They mostly used the so-called "fishtail," or just "Fell" points, a widespread Paleo-American marker. Despite that, they exploited different faunal species, including extant and extinct fauna. At the Salto Department in the northwestern region of Uruguay, on the Itaperibí Grande creek shore, archaeological remains of bones and stones were recovered. One of the most remarkable is a fragmented fossil femur of Lestodon armatus, a mega-mammal giant ground sloth. In its anterior face, this specimen shows diverse kinds of marks. However, no clear association among the findings was documented. Then, in order to check the possible relationship between the bone and the artifacts, the specimen was subjected to radiocarbon dating and it was analyzed in detail from a taphonomic perspective to evaluate the origin of the marks. The radiocarbon assay indicates that the specimen belongs to the last millennium of the Pleistocene. The date is relevant as it is one of the few assays obtained on a sample from that time. The taphonomic study revealed that the marks were not produced by human activity, hence, its primary relationship with the stone artifacts is uncertain. Despite that, these data make an important contribution to the knowledge about the fauna contemporaneously living with the earliest hunt-How to cite this paper: Nami, H. G.,

Background. The Sousa Formation contains the richest dinosaur ichnofauna from the Early Cretaceous Rio do Peixe Basin, Northeastern Brazil. Occurs eventually ornithopod tracks, which are found also in the Antenor Navarro and Piranhas Formations. Together with one trackway from the Botucatu Formation, some isolated tracks from the Cenomanian São Luís Basin, and some trackways from the Early Cretaceous Corda Formation, at the moment, these occurrences indicates the only definitive presence of ornithopods in the Mesozoic of Brazil. Material & Methods. In 2015, a fieldwork was held to investigate potential dinosaur tracks in new ichnosites from the Sousa Formation. All the tracks were photographed individually using a digital camera Nikon Coolpix P520. The paleoichnological terminology and morphometric parametrers follows Thulborn (1990), Marty (2008) and Castanera et al. (2013). A plastic sheet was used for drawing the tracks. Directions and measurements of each dinosaur track, as well as the entire outcrop, were taken in situ. Results. The Pereiros ichnosite represents a new occurrence of dinosaur tracks from the Sousa Formation. The dinosaur ichnofauna comprises a medium-sized, bipedal ornithopod trackway, a single ornithopod track and one pair of theropod tracks. Discussion. The ornithopod trackway is characterized by plantigrade, tridactyl, mesaxonic, subsymmetrical and wider than long pes tracks, with large and rounded heels, and short and wide digit impressions. It is referred to the ichnofamily Iguanodontipodidae, previously reported for the Sousa beds. Two medium-sized theropod tracks assigned to Irenesauripus also occurs, representing an expansion of the paleobiogeographical record for this unusual ichnotaxa. The new record of Irenesauripus from the Sousa Formation shows an unusual pattern with morphological similarities to theropods tracks from the Lower Cretaceous Feitianshan Formation of Sichuan, China (Xing et al., 2013). According to Xing et al. (2011), the Chinese tracks preserve partial metatarsal pads that are not distinct from their respective metatarsophalangeal regions. Xing et al. (2011) noted the unusual elongate digit II claw impression, indicating that digit II of the trackmaker possessed a long claw, longer than on any of the other digits. Conclusions. The outcrop studied represents the nineteenth dinosaur tracksite in the Sousa Formation and gives further evidence of the rather rare ornithopod dinosaurs in the Cretaceous of Brazil.