The surprising diversity and recent dramatic decline of freshwater mussels in North America have been well documented, although inventory efforts to date have been concentrated in the eastern United States. Unlike their eastern counterparts, western freshwater mussels have received comparatively little attention. The accurate identity of western lineages is a necessary component for future inventory, monitoring, and ecological work involving these taxa. Here we initiate a study involving the most speciose genus (Anodonta) in western North America, incorporating information about type localities and type specimen morphology and describing the discovery of three highly divergent lineages among four western Anodonta species. In a limited phylogenetic analysis, we find (1) that A. californiensis/nuttalliana and A.oregonensis/kennerlyi are distinct, highly divergent clades, and (2) that A. beringiana is more closely allied with A. woodiana, an Asian species, than either of the other two western North American clades. We were largely unable to resolve the placement of these three clades with respect to other anodontines, and suggest the need for a broader phylogenetic framework. We recommend, however, that the existence of these three deeply divergent groups be considered in the development of regional monitoring, conservation and research plans despite the taxonomic uncertainty.

We evaluated associations between physicochemical aquatic habitat variables and presencelabsence of Pyrgulopsis trivialis, a hydrobiid snail, in selected springs at Three Forks springs and Boneyard Bog springs in the White Mountains of eastcentral Arizona. Three Forks springs were characterized by more cobble/boulder and graveltpebble substrates, higher water temperature, lower conductivity, higher pH, and deeper water than Boneyard Bog springs, which were characterized by more siltlsand substrates and watercress. The presence of P. trivialis was associated with gravellpebble substrates, shallower water, higher conductivity, higher pH, and presence of Physa gyrina.

The San Bernardino springsnail (Pyrgulopsis bernardina) inhabits springs in the upper San Bernardino River (SBR) basin in southeastern Arizona and northeastern Sonora. Loss of populations in Arizona associated with habitat degradation has resulted in concern for the continued persistence and viability of the species. Springsnails at the Arroyo San Bernardino (ASB) sub-basin in Sonora are considered P. bernardina but this has not been validated through genetic studies to receive legal protection. The species of Pyrgulopsis detected in the Arroyo Cajon Bonito (ACB) sub-basin in Sonora sites is not known. The goal of this study is to provide genetic information to resource managers to clarify the taxonomic relationships between populations of Pyrgulopsis in the upper SBR basin in Sonora with those historically found at the type locality in Arizona based on cytochrome oxidase 1 (COI) gene fragment. COI fragments from the two sub-basins samples in Sonora, confirms that Pyrgulopsis are conspecific with type locality samples from Arizona. Maximum parsimony and maximum likelihood analysis of all populations, agree with the current systematics of the species. Monophyly of all populations of P. bernardina was observed, and populations within each sub-basin form two monophyletic clades. Conservation planning should recognize the two sub-basins genetic divergence. Within the ASB clade, genetic relationships suggest historical connectivity with the type locality in Arizona.

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