Ancient genomes in South Patagonia reveal population movements associated with technological shifts and geography.

Archaeological research documents major technological shifts among people who have lived in the southern tip of South America (South Patagonia) during the last thirteen millennia, including the development of marine-based economies and changes in tools and raw materials. It has been proposed that movements of people spreading culture and technology propelled some of these shifts, but these hypotheses have not been tested with ancient DNA. Here we report genome-wide data from 20 ancient individuals, and co-analyze it with previously reported data. We reveal that immigration does not explain the appearance of marine adaptations in South Patagonia. We describe partial genetic continuity since ~6600 BP and two later gene flows correlated with technological changes: one between 4700-2000 BP that affected primarily marine-based groups, and a later one impacting all <2000 BP groups. From ~2200-1200 BP, mixture among neighbors resulted in a cline correlated to geographic ordering along the coast.

Modern guanaco (Lama guanicoe, Camelidae) bezoars: An approach towards identification in the fossil record.

OBJECTIVE: Provide a frame of reference for the recognition and interpretation of bezoars recovered from archeological and paleontological sites. MATERIALS: 49 bezoars from extant guanaco (Lama guanicoe) were analyzed and compared with five objects previously identified as bezoars, recovered from Holocene archeological sites of the Argentine Pampas. METHODS: Size, shape, weight, external and internal features, and mineralogical composition were evaluated in both modern and archeological bezoars using nondestructive and destructive methods. RESULTS: Modern and archeological bezoars are formed by calcium phosphate and display great morphological variability linked to ante-mortem processes, taphonomic alterations, and anthropic activity. CONCLUSIONS: Morphometry, along with external and internal features and mineral composition, are useful tools for the identification and interpretation of bezoars in the fossil record. SIGNIFICANCE: This study offers new information on the etiology, mechanisms of formation, and means of interpreting the presence of bezoars, a common pathology in South American camelids, in the fossil record. LIMITATIONS: The features of fossil bezoars do not provide accurate identification of the animal that produced them. SUGGESTIONS FOR FURTHER RESEARCH: Further analyses on modern bezoars belonging to other species of mammals are needed in order to enhance the interpretation of bezoars in the fossil record.