ZooMS for birds: Discrimination of Japanese archaeological chickens and indigenous pheasants using collagen peptide fingerprinting

Zooarchaeology by mass spectrometry (ZooMS) is a new approach that has rapidly evolved in the last decade and is used for identifying zooarchaeological bones from species such as mammals, fish, reptiles (sea turtle), and amphibians. However, owing to the predicted slow evolution rate of collagen within the class Ayes, no attempts were made to identify zooarchaeological bird bones at species level by ZooMS. To explore the usefulness of the ZooMS approach for bird bones, we analyzed bone collagen peptide of modern and archaeological chickens and middle-sized Japanese wild indigenous pheasants using time of flight mass spectrometry (TOF-MS) and liquid chromatography mass spectrometry (LC-MS). We found that modern chickens and Japanese wild indigenous pheasants showed different peptide mass peaks. Based on this difference, we studied five archaeological Phasianidae bones identified as chicken or wild pheasant by morphological analyses from Hiroshima castle site, Hiroshima Prefecture, Japan. The identification results of TOF-MS and LC -MS analyses were concordant, and the results agreed with the morphological identification in all of the bones. These results clearly showed the usefulness of the ZooMS approach for discriminating archaeological bird bones as well as those of other vertebrate classes.