Dietary and palaeoenvironmental inferences in Neolicaphrium recens Frenguelli, 1921 (Litopterna, Proterotheriidae) using carbon and oxygen stable isotopes (Late Pleistocene; Uruguay)

The Proterotheriidae (Early Palaeocene-Late Pleistocene) were small to medium sized cursorial native South American ungulates (Order Litopterna), having had its diversity peak in the Miocene. During the Pleistocene, the proterotheriid diversity decreased to a single species, Neolicaphrium recens Frenguelli (1921), and few specimens are available from a relatively narrow area at medium latitudes of South America. The first study using stable isotopes (delta C-13 and delta O-18) as proxies is provided here, in order to known dietary preferences and testing previous environmental inferences. The analysed specimens belong to outcrops with OSL ages of 40-30 ka (Late Pleistocene, Sopas Formation of northern Uruguay). The delta C-13 results of both specimens suggest that at this latitude and tempo, N. recens had browser-feeding preferences, mostly a C-3 diet of open canopy forest in an environment of semi-open woodland or forested savannahs and that C-4 vegetation would have had a small fraction in their diet. delta O-18 data suggests a diet composed mostly by fruits, follow by floor plants, with few indication of a folivore diet. The specialized forest browsing diet does not significantly vary based on its site of origin, since both specimens remain in the same isotopic range.