TAXONOMY AND DISTRIBUTION OF BENTHIC DIATOMS FROM MONO LAKE, CALIFORNIA, USA

The benthic diatom flora of Mono Lake is described from samples taken from three localities at depths of approximately 1, 5, and 10 meters on rock and sediment substrates. Relative abundances of 30 taxa were recorded from duplicate counts of 500 valves from each of 18 samples. Dominant taxa included Navicula crucialis, Nitzschia frustulum, N. latens, N. reimerii sp. nov., N. monoensis, sp. nov. and Anomoeoneis sphaerophora var. minor var. nov.; taxonomy, morphology, and distribution of these taxa are considered. Navicula crucialis, previously recorded from saline lakes in North Africa and highly variable in outline, was most abundant in sediment samples. Anomoeoneis sphaerophora var. minor, Nitzschia reimeri, and N. monoensis were most abundant in deeper waters whereas both N. latens and N. frustulum occurred most frequently in collections from shallow waters. Smaller individuals of N. latens were broader than larger specimens, and some N. frustulum cells resembled N. austriaca. Nitzschia monoensis has numerous girdle bands and prominent external distal raphe ends. Navicula crucialis, A. sphaerophora var. minor, and Nitzschia monoensis were observed with internal valves.