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.