Hosca brusca is one of the two sudamericid genera found in Santa Lucia, and the only local gondwanathere genus that's monotypic. This bear sized animal is characterised by a thinner snout than other gondwanatheres, which would have given it a somewhat bear-like profile in life. This is likely due to a more selective diet, a trend seen among several herbivorous mammals and dinosaurs. Isotope ratios suggest it fed primarily on cycads and conifers, represented in the formation by araucarias and podocarps. Biomechanical studies suggest its thin snout was still capable of a full palinal stroke and processing hard plant matter, so much like other "picky" herbivores it probably picked individual or few more nutrious leaves and branches while other herbivores bulldozed through. Phylogenetic studies indicate that it was closely related to Cretaceous genera like Gondwanatherium, likely representing a low-latitude radiation supplanted by migrants from Patagonia in the late Paleocene. This might explain its speciation in comparison to the more generalistic Glyptoguy, which is closely related to Patagonian taxa.
