Cuatro Cienagas

The Cuatro Ciénegas Valley (“Four Marshes” in Spanish) is an internally draining basin in the northern state of Coahuila. A true biodiversity hotspot, it is famous among biologists for the high percentage of endemic species—especially freshwater fishes, but also a few species of reptiles found nowhere else, including the aquatic Coahuilan Box Turtle (Terrapene coahuila), Cuatro Cienegas Slider (Trachemys taylori), and Cuatro Cienegas Alligator Lizard (Gerrhonotus lugoi). In addition to the endemic herps, there are a few additional aquatic/riparian associates that have colonized the basin, including Texas Indigo Snakes (Drymarchon corais erebennus), Diamondback Watersnakes (Nerodia rhombifer), and Spiny Softshells (Apalone spinifera emoryi). It is a land of pronounced contrast—spring-fed pools juxtaposted with some of the Chihuahuan Desert’s most arid landscapes. A handful of Gray-Banded Kingsnakes have been found within the Cuatro Ciénegas basin, including the second known Mexican specimen nearly 70 yrs ago. 2400 ft/730 m elev. (July 1996).