Parasites as chronological indicators: ancient DNA of Nematodirus spathiger (Nematoda: molineidae) in camelid coprolites from Patagonia Argentina

Abstract

Coprolites from archaeological sites could contain parasitic remains. These remains are identified according to morphological characters and DNA analysis. Accurate diagnosis allows knowing part of the parasitic assemblages of mammals during Holocene. Coprolites of camelids have been recovered in different archaeological sites of Patagonia. In the present work, larvated eggs attribute to Nematodirus sp. isolated from guanaco coprolites were studied to their accurate identification. Coprolites were collected in the archaeological site Alero Destacamento Guardaparque (ADG) located in the Meridional Patagonia. Eggs and their larvae were assigned to Nematodirus spathiger Railliet, 1896 by morphometric analysis under light microscope. Ancient DNA (aDNA) analysis of two larvated eggs isolates confirmed parasites identity. DNA sequences of mitochondrial fragment of cytochrome c oxidase subunit I (coxl) gene showed a 99% identity with other N. spathiger sequences. Also, sequences of 5.8 S ribosomal DNA (rDNA) fragment confirmed coxl results with an identity of 98%. Previous studies on camelids prehispanic samples not reported N. spathiger, but this parasite have been reported in current guanacos in Patagonia. Nematodirus spathiger is considered a specific bovine and sheep parasite suggesting that its occurrence in guanacos is a consequence of host colonization by exotic enteroparasites that arrived in Patagonia with European cattle. Consequently, this finding demonstrates its usefulness as a temporary indicator to discuss the antiquity of the upper layers of the ADG archaeological site.