Assessing the reliability of criteria used to identify postcranial bones in sheep, Ovis, and goats, Capra

Criteria developed to distinguish between selected postcranial elements of sheep and goats are evaluated using modern specimens from the collections of the Field Museum of Natural History, the National Museum of Natural History, and the Museum of Anthropology and the Museum of Zoology, University of Michigan. Elements considered are: the distal humerus, proximal and distal radius, distal tibia, distal metapodials, astragalus, calcaneus, and the first and second phalanx. This evaluation includes an assessment of 1385 elements from 49 goat and 84 modern sheep skeletons. It also includes a blind test on elements drawn from 20 specimens taken by six analysts with differing levels of experience. Overall, the criteria evaluated are highly reliable, especially in goats and only slightly less so in sheep. A major exception is the distal tibia, where diagnostic criteria tested proved substantially less reliable than other criteria evaluated here. Strongly positive results were also obtained when the sample was partitioned by sex, domestic status, and age. Results of the blind test show some variability depending on the level of experience of the analyst, underscoring the need for training and access to adequate modern reference collections before attempting to apply these criteria to archaeological assemblages. The results of this assessment stand in stark contrast to those obtained in an earlier assessment of the reliability of criteria used to distinguish between mandibles and mandibular teeth of sheep and goats. In all but a few teeth, dental criteria proved to be much less reliable, especially in goats. They were also significantly less reliable in the identification of both younger and older animals. Unlike dental criteria, there are no biases introduced by variable reliability of postcranial criteria that distort taxon-specific harvest profiles based on long-bones.