Olivella Species Differences
References to Olivella shell source material in the archaeological literature are replete with out-of-date species nomenclature. Olivella shell beads of western North American were first studied in detail by E. W. Gifford (1947:10, 11, 20, 3436), who reported use of Olivella biplicata, O. pycna and O. undatella. Bennyhoff and Hughes (1987:98, 117, 121), citing other authors, noted six source species, O. biplicata, O. baetica, O. dama, O. pycna, O. undatella and O. pedroana. In recent years, O. pycna has been subsumed under O. pedroana and O. undatella has been subsumed under O. dama, leaving only four pertinent species for archaeological studies.