CONICET | Buscador de Institutos y Recursos Humanos

The record of Palaeogene cingulate xenarthrans in low latitudes is very poor. In this sense, the cingulate fauna from the YurúaRiver near Santa Rosa in eastern Perú is important because it is one of the oldest known from the Palaeogene from Perú and because of its tropical latitudinal position. Although remains are scarce, we recognize three new taxa: two species of Astegotheriinae (Dasypodidae); Parastegosimpsonia peruana nov. gen. et sp., of small size, related to Eocene species from Patagonia, and another new species, ?Parastegosimpsonia, which consists of an incomplete osteoderm representing the largest species of this tribe. A third species, Yuruatherium tropicalis nov. gen. et sp., of indeterminate suprageneric rank, shares features with Machlydotherium Ameghino (Casamayoran-Tinguirirican SALMA middle Eocene-early Oligocene of Patagonia) and is similar to Eocoleophorus Oliveira et al. (Deseadan SALMA late Oligocene of Brazil). Also we assign to Yuruatherium nov. gen. the species ?Machlydotherium intortum (from the late Eocene of Patagonia). Sediments bearing these cingulates also yielded rodents, marsupials, and notoungulates, among the most frequent mammals. The absolute age of the sediments is unknown, but an estimated age is inferred from the studies of mammalian assemblages. Even so the age of the Santa Rosa local fauna is still controversial and, given the groups taken into account, could be from early Eocene to late Oligocene. According to sequences of southern cingulate faunas (especially those of Dasypodidae), the cingulates from Santa Rosa also suggest an age between the late Eocene to early Oligocene for the fauna. Nevertheless, the very low latitude of Santa Rosa local fauna should be taken into account because in lower latitudes it is not uncommon to find taxa with a more generalized set of characters than those displayed by taxa of contemporary levels in higher latitudes.

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