Eurycea nana

The San Marcos salamander (Eurycea nana) is a small species of aquatic, lungless salamander native to the United States, endemic to Spring Lake and a small region of the headwaters of the San Marcos River near Aquarena Springs, in Hays County, Texas. It is one to two inches long, with a slender body and external gills, and is a reddish-brown in color. The San Marcos salamander has been federally listed as a threatened species since 1980. Due to its extremely limited geographic range, it is threatened by a number of things, but primarily from the contamination of ground water sources and heavy dependence of Central Texas cities upon the Edwards Aquifer for water.