Applying Discriminant Function Analysis of Atlas and Axis Vertebrae of the Toothed Whales for Aiding Species Identification of Zooarcheoogical Specimens
Toothed whale remains are common finds from archaeological sites across Japan, suggesting a key marine resource of subsistence in this region. However, the actual state of cetacean exploitation at each archaeological site remains unclear due to most assemblages consisting of primarily postcrania that are similar in morphology and are difficult to identify. Here we attempted to establish taxonomic identification criteria for atlas and axis vertebrae of modern toothed whales using discriminant function analysis (DFA) and applied the criteria to zooarchaeological specimens. Canonical DFA was effective at classifying the modern specimens of 18 toothed whale species in a hierarchical classification system, with a high successful classification rate at the superfamily (97.1%), family (89.6%), and subfamily (78.9%) levels. At the species level, six received the highest score (100.0%) for correct identification rate for each species, while four other species had sufficiently high correct identification rates (above 80.0%). The established canonical discriminant functions were applied to 44 zooarchaeological specimens from two early Jomon and one Okhotsk culture period sites in Japan. Twenty-seven specimens were identified in a hierarchical taxonomic classification scheme without contradiction, six species including four species not found in the previous morphological analysis and three not distributed around the sites, were found. These suggested that DFA-based classification could be useful for taxonomic identification at the family level and higher, and thus, effective in improving the identification quality of zooarchaeological specimens. Adding more modern reference specimens in the dataset may further improve the certainty and accuracy of identification for future work.
University of Groningen