Cyprinodon pachycephalus
Overview
The bighead pupfish, known in Spanish as cachorrito cabezon, is a critically endangered species of pupfish in the family Cyprinodontidae. It is endemic to an area covering less than 1 km2 (0.4 mi2) at San Diego de Alcala in the Conchos River basin, Chihuahua of Mexico. It lives in hot springs, their outflows and an impoundment pool in water that ranges at least from 25 to 49 °C (77–120 °F).
Cyprinodon pachycephalus faces severe threats from habitat modification and water extraction in its extremely limited desert spring systems. The species is vulnerable to groundwater pumping that reduces spring flow, while introduced species and habitat degradation from human activities further compromise its survival. Climate change poses an additional long-term threat through increased temperatures and altered precipitation patterns affecting already fragile spring ecosystems.
Habitat
This critically endangered pupfish is endemic to isolated desert springs and associated pools in arid regions of Mexico. It inhabits shallow, warm spring-fed waters with specific temperature and salinity requirements that have remained stable over thousands of years.
