Paleoparasitological survey of coprolites of Darwin’s ground sloth Mylodon darwini (Xenarthra, Folivora: Mylodontidae) from Cueva del Milodón Natural Monument, Chilean Patagonia

Despite the ubiquity of parasitism, the knowledge regarding fossil parasites remains fragmentary. As an example, South American clade Xenarthra was a predominant group of mammals during the Cenozoic; however, its paleoparasitological knowledge has many gaps, with only a few reports in armadillos and fewer in ground sloths. Darwin’s ground sloth (Mylodon darwini) was a mega mammal widely distributed in the Neotropics; however, its parasitic fauna is poorly known with the sole report of unidentified nematode eggs. Thus, this study aimed to determine additional host-parasite associations and to discuss its possible role as a reservoir of zoonotic parasites. Fifty-two coprolites from Cueva del Milodon Natural Monument were analyzed through coprological analysis to determine the presence of parasites. From these, 18 (34.62%) coprolites had parasitic helminth eggs belonging to 6 taxa: Calodium sp., Ascaridida, Hymenolepididae, Anoplocephalidae, Taeniidae, and Digenea. All these findings are new records for this sloth; also, two of them, Calodium sp. and Anoplocephalidae, have represented a risk for the health of ancient humans. Eggs of Calodium were similar to those previously isolated from ancient humans in Patagonia. Thus, Darwin’s ground sloth has represented a potential reservoir of zoonotic helminths, which is interesting considering this species was in close contact with humans in ancient Patagonia. Thus, additional collaboration with paleontologists is highlighted considering the incipient development of paleoparasitology in Chile, which could elucidate the presence of important pathogens, contributing to a better understanding of the evolution and changes in the distribution and virulence of certain parasites through time.