TEXAS BLIND SALAMANDER
TEXAS BLIND SALAMANDER. The Texas blind salamander (Typhlomolge rathbuni) was discovered in 1895 during the completion of a well to supply the Federal Fish Hatchery in San Marcos. A cavern in the Edwards Limestone formation, penetrated at 196 feet, was the source of the water for the hatchery and also the source of the salamander. The original description of the salamander was done in 1896 by Leonhard Stejneger, Curator of Reptiles and Amphibians at the United States National Museum. Few specimens of the salamander were collected after that time until extensive netting of the well was started in the late 1970s by Glenn Longley, professor of biology at Southwest Texas State University and director of the Edwards Aquifer Research and Data Center. During collections in the 1980s numerous specimens were salvaged as they were drawn out of the groundwater system by the artesian flow from the well. During that same time Longley collected the first specimens from San Marcos Springs.
A diverse community of more than forty macroinvertebrates exists in the same habitat. Many of these are food for Texas blind salamanders, which are known only from the Edwards Aquifer in the San Marcos vicinity. They have been collected only from the following locations: the artesian well at the SWTSU Aquatic Station (formerly the Federal Fish Hatchery well), San Marcos Springs, Wonder Cave, Ezell's Cave, Johnson's Well (now filled), Primer's Fissure "well," and Rattlesnake Cave. This species was the first animal placed on the federal endangered species list (1967); in the 1990s it was listed as endangered by both the state and federal governments. The Texas blind salamander is of considerable scientific interest due to its uniqueness. It is considered to be the most advanced troglobitic salamander in the world. A closely related form, the Blanco blind salamander, is known from one locality (a cave opened in the mid-1950s by a gravel quarry operation) in the bed of the Blanco River immediately upstream from the Interstate 35 bridge in San Marcos. This form has not been collected since, due to floods on the Blanco which closed the cave; only one known specimen exists. In the 1990s the Texas blind salamander was endangered most from the prospect of overpumping the Edwards Aquifer and therefore drawing the water levels down, possibly dewatering some habitat. A greater threat was from the potential intrusion of poor-quality, highly saline water into the habitat of the salamander due to the overpumping.
Lazare Botosaneanu, ed., Stygofauna Mundi: A Faunistic, Distributional, and Ecological Synthesis of the World Fauna Inhabiting Subterranean Waters (Including the Marine Interstitial) (Leiden, Netherlands: Brill, 1986). Glenn Longley, "The Edwards Aquifer: Earth's Most Diverse Groundwater Ecosystem?," International Journal of Speleology 11 (1981). Glenn Longley, Status of the Texas Blind Salamander (Endangered Species Report 2, Albuquerque, New Mexico: U.S. Fish and Wildlife Service, 1978).