The Mogollon Narrowheaded gartersnake (Thamnophis rufipunctatus) and the Northern Mexican gartersnake (Thamnophis eques megalops) are both listed as Threatened under the Federal Endangered Species Act. Both species have a strong association with aquatic habitats, and these habitats have been highly altered from impoundments, land-use changes, and the introduction and spread of non-native aquatic species, which have contributed to declines in Arizona and New Mexico over the last 30-40 years. We characterized 125 microsatellite loci per species to generate genetic toolsets for use in long term genetic monitoring of populations. We evaluated microsatellite loci for missing data and several variability thresholds, which resulted in 108 [...]