Species: Anodonta oregonensis

G - 200,000-2,500,000 square km (about 80,000-1,000,000 square miles) - G - Originally, this species ranged from California to Alaska and east to Nevada and Utah, but many older museum specimens examined from northern areas are likely <i>Anodonta beringiana</i> (Nedeau et al., 2005). Clarke (1981) lists the distribution of this species as the Fraser and Columbia River systems in southern British Columbia south to central California, but absent from Vancouver Island. Early reports of this species occurring eastward to Great Salt Lake and Weber and Jordan basins, Utah (see Oliver and Bosworth, 1999), are likely in error as this is likely a different species (K. Mock, pers. comm., 2006). Mock et al. (2004; 2005) found a lack of resolution (very little nuclear diversity) in phylogenetic reconstructions of <i>Anodonta </i>(<i>A. californiensis</i>, <i>A. oregonensis</i>, <i>A. wahlamatensis</i>) populations in the Bonneville Basin, Utah, but there was a tendency for the Bonneville Basin <i>Anodonta </i>(tentatively <i>A. californiensis</i>) to cluster with <i>A. oregonensis</i> from the adjacent Lahontan Basin in Nevada.