Can salmonids (Oncorhynchus spp.) be identified to species using vertebral morphometrics?

Remains of anadromous Pacific salmon and trout (genus Oncorhynchus) are common in archaeological sites from California to Alaska; however, morphological similarity generally precludes species identification, limiting the range of questions that salmonid remains can address in relation to past human use and ongoing efforts in conservation biology. We developed a relatively simple, rapid, and non-destructive way to classify salmon and trout vertebrae from archaeological contexts to species using length, height and the ratio of length to height. Modern reference material was obtained from all seven anadromous Oncorhynchus species native to the west coast of North America. A minimum of ten adult Chinook (Oncorhynchus tshawytscha), chum (Oncorhynchus keta), coho (Oncorhynchus kisutch), pink (Oncorhynchus gorbuscha), and sockeye salmon (Oncorhynchus nerka) and cutthroat (Oncorhynchus clarki clarki) and steelhead trout (Oncorhynchus mykiss) were skeletonized and vertebra length and height were measured. Morphometric analyses compared species classification success based on Linear Discriminant Analysis (LDA), Classification and Regression Trees (CART), and randomForest, with CART performing the best. Classification analyses used all seven species individually, but because of considerable overlap among several species we also conducted analyses on four species groupings. We assigned Chinook salmon and cutthroat to their own groups based on their dissimilarities from each other and the other species. The remaining species were divided into two group complexes (a) chum, coho, and steelhead; and (b) pink and sockeye. When we grouped species according to similar morphology, CART overall success rates increased, ranging from 92 to 100%. Individual species with the highest successful classification rates using CART were Chinook salmon and cutthroat, from 92 to 100%, respectively. We applied our classification to an assemblage of ancient (1000–3000 year old) salmonid vertebrae from the Swiftwater Rockshelters excavations on the upper Wenatchee River in Washington State, U.S.A.     

Writing the History of the “Persian Arabs”: The Pre-Islamic Perspective on the “Naṣrids” of al-Ḥīrah

Modern scholarship on Arabs in the pre-Islamic period has focused on Rome's Arab allies—the so-called “Jafnids” or “Ghassānids,” with much less attention paid to Persia's Arab allies, the so-called “Na?rid” or “Lakhmid” dynasty of Arab leaders at al-?īrah in Iraq. This article examines select pre-Islamic sources for the Persian Arabs, showing that even with the meager evidence available to us, and the lack of archaeological material, it is possible to draw a relatively complex portrait of the Persian Arabs. This article situates the Persian Arabs as important figures in some key themes and phenomena of late antiquity, such as the growth of Christian communities, the conflict between Rome and Persia, and the struggle for influence in the Arabian peninsula.