Brasiliochoerus stenocephalus (Lund in Reinhardt, 1880), a large extinct peccary in late Pleistocene beds of Uruguay: Comparative, isotopic and paleoecological studies

Abstract

Tayassuids entered South America, forming part of the Great American Biotic Interchange, and have had success in South America since the Pliocene, evolving into six genera, and several species have been described. The extinct peccary Brasiliochoerus stenocephalus in late Pleistocene beds of northern Uruguay (the Sopas Formation) is substantiated based on an almost complete and well-preserved skull. A set of associated diagnostic features supports a confident assignment of the material to this extinct species. This peccary was present in the last 40 ka in this area. It was unearthed together with Tayassu pecari, which is found in the same beds, indicating the co-occurrence of both taxa. According to a quantitative analysis, B. stenocephalus is characterized by having a skull much larger than those of T. pecari and Dicotyles tajacu and equal to or larger than the largest individuals of Parachoerus wagneri. However, if only dental variables are computed, despite having a large skull, it shares the morphospace with T. pecari, with P. wagneri being the species with the largest teeth. A high consumption of C3 plants is suggested by δ13C results, and the same kind of browser diet could be roughly inferred for B. stenocephalus and T. pecari. Considering δ 18O and δ13C together, both specimens seem to have eaten mostly in the canopy frugivore range, including leaves and some floor plants. T. pecari seems to have not significantly varied its feeding behavior, at least between ca. 40 ka and today. The isotopic results support a browser semiopen woodland lifestyle in C3–C4 grassland to open-canopy environments reinforced by accompanying fauna.