The Sonoyta mud turtle, Kinosternon sonoriense longifemorale, is endemic to a small area in south- western Arizona and northwestern Sonora. The only U.S. population, at Quitobaquito, declined from several hundred in the 1950s to fewer than 100 in the 1980s (Arizona Game and Fish Department 2005). A decline in 1989-90 was attributed to drought and high temperatures.
The subspecies is listed as an ESA Candidate (FWS) and is threatened by groundwater pumping, possibly exacerbated by reduction of surface flow by transpiration in dense thickets of exotic saltcedar (Tamarix ramosissima) in the Rio Sonoyta. It is not known or thought to be significantly impacted by border-related issues such as pollution, wildfire, off-road traffic, other exotic species, although poaching is known at Quitobaquito and could be a threat.