The Blanco blind salamander (''Eurycea robusta'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of aquatic,

lungless salamander Plethodontidae, or lungless salamanders, are a family of salamanders. Most species are native to the Western Hemisphere, from British Columbia to Brazil, although a few species are found in Sardinia, Europe south of the Alps, and South Korea. In ...

native to the United States. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to a small region of the Blanco River near

San Marcos San Marcos is the Spanish name of Saint Mark. It may also refer to: Towns and cities Argentina * San Marcos, Salta Colombia * San Marcos, Antioquia * San Marcos, Sucre Costa Rica * San Marcos, Costa Rica (aka San Marcos de Tarrazú) ...

Hays County, Texas Hays County is located on the Edwards Plateau in the U.S. state of Texas. Hays County is part of the Austin-Round Rock metropolitan area. As of the 2020 census, its official population had reached 241,067. The county seat is San Marcos. Ha ...

. Its habitat, deep in

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

karst, makes collecting specimens for research particularly problematic. It is known from only a single specimen, collected in the 1950s. The Blanco blind salamander is considered a lost species, as it is unknown whether it is still alive or not. Four specimens were discovered in 1951 by a gravel company digging in the dry bed of the Blanco River. Two were eaten by a heron, one was lost and the final specimen was sent to the

University of Texas at Austin The University of Texas at Austin (UT Austin, UT, or Texas) is a public research university in Austin, Texas. It was founded in 1883 and is the oldest institution in the University of Texas System. With 40,916 undergraduate students, 11,07 ...

for research. Any extant members of the species are believed to live in the

Edwards Aquifer The Edwards Aquifer is one of the most prolific artesian aquifers in the world. Located on the eastern edge of the Edwards Plateau in the U.S. state of Texas, it is the source of drinking water for two million people, and is the primary water s ...

. Researchers are using environmental DNA analysis to assess whether it still lives, but are hampered by the fact that no extant viable DNA samples exist. For that reason, they are using similar related species, such as the

Texas blind salamander The Texas blind salamander (''Eurycea rathbuni'') is a rare cave-dwelling troglobite amphibian native to San Marcos, Hays County, Texas, specifically the San Marcos Pool of the Edwards Aquifer. Description The species has a broad, flat, snout ...

, as a proxy.

References

* (2000): Phylogenetic relationships of central Texas hemidactyliine plethodontid salamanders, genus ''Eurycea'', and a taxonomic revision of the group. ''Herpetological Monographs'' 14: 1-80. * (2001): A new species of subterranean blind salamander (Plethodontidae: Hemidactyliini: ''Eurycea'': ''Typhlomolge'') from Austin, Texas, and a systematic revision of central Texas paedomorphic salamanders. ''Herpetologica'' 57: 266–280.
Amphibian Species of the World: ''Eurycea robusta''IUCN Red List: ''Eurycea robusta''Discover Life: ''Eurycea robusta''

Robusta ROBUSTA (Radiation on Bipolar for University Satellite Test Application) is a nano-satellite scientific experiment developed by the University of Montpellier students as part of a Centre National d'Études Spatiales (CNES) call for student projects ...

Cave salamanders Amphibians described in 1978 {{Plethodontidae-stub