Parasites in micromammal fecal pellets throughout the Late Holocene ("Cueva Peligro" paleontological site, Patagonia, Argentina).

Parasite remains in micromammal fecal pellets collected from the paleontological site "Cueva Peligro" (CP 43°40'18"S, 66°24'52"W), Chubut Province, Argentina, were examined. The samples were obtained from two grids, dated between 1220 ± 70C yr B.P. to modern dates. Fecal pellets were whole processed, rehydrated, homogenized, and examined via light microscopy. Eggs of parasites found were measured and photographed. Fecal pellets belong to one or more insectivore to omnivore unidentified micromammal species, possibly sigmodontine rodents. A high number of helminthes species was recorded (11 species), eight nematodes, two anoplocephalid cestodes and one acanthocephalan species. The sigmodontine-parasite relationship varied throughout the studied period and between studied grids. This is the first time that Gongylonema sp. and Syphacia sp. are reported from ancient times from Patagonia. The obtained results contribute to the knowledge of parasite assemblages associated to native South American sigmodontine rodents and the zoonoses present in the area throughout the lasts 1200 years.