Very active, shiny black beetle crawling rapidly on somewhat saline floodplain ground just south of section of stream channel restored in 2018. Ca 75% bare ground with scattered, non-native, rhizomatous grasses. At least 3 of these beetles seen within 1 m^2.
Elevation ca 4000 feet. Disturbed, shrubby riparian corridor on stream restoration site within a patchwork of native and non-native grassland.

Keyed to genus in Arnett et al. 2002. Bembidiini because mesocoxae completed enclosed by sterna; 2 supraorbital setigerous punctures above each eye; and last segment of maxillary palpus reduced, subulate. Characters taking me to Bembidion included apex of protibia truncate instead of transverse and maxillary palpomere 4 cylindrical, not conical. Help with subgenus or species would be greatly appreciated.