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

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of aquatic,

lungless salamander Plethodontidae, or lungless salamanders, are a family of salamanders. With over 500 species, lungless salamanders are by far the largest family of salamanders in terms of their diversity. Most species are native to the Western Hemisphere, from B ...

native to the United States. It is

endemic Endemism is the state of a species being found only 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 foun ...

to a small region of the Blanco River near San Marcos in

Hays County, Texas Hays County is a county in the central portion of the U.S. state of Texas. It 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. Hays, alon ...

. Its habitat, deep in

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

karst Karst () is a topography formed from the dissolution of soluble carbonate rocks such as limestone and Dolomite (rock), dolomite. It is characterized by features like poljes above and drainage systems with sinkholes and caves underground. Ther ...

, 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 with it being on Re:wilds Search For Lost Species initiative, as it is unknown whether it is still alive or not. Four specimens were discovered in 1951 by a

gravel Gravel () is a loose aggregation of rock fragments. Gravel occurs naturally on Earth as a result of sedimentation, sedimentary and erosion, erosive geological processes; it is also produced in large quantities commercially as crushed stone. Gr ...

company digging in the dry bed of the Blanco River. Two were eaten by a

heron Herons are long-legged, long-necked, freshwater and coastal birds in the family Ardeidae, with 75 recognised species, some of which are referred to as egrets or bitterns rather than herons. Members of the genus ''Botaurus'' are referred to as bi ...

, 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 university, public research university in Austin, Texas, United States. Founded in 1883, it is the flagship institution of the University of Texas System. With 53,082 stud ...

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 su ...

. 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 and endangered cave-dwelling troglobite amphibian native to San Marcos, Hays County, Texas, specifically the San Marcos Pool of the Edwards Aquifer. This species resembles the olm, a ...

, as a proxy.

Description

The Blanco blind salamander has a stout body, reduced eyes, robust limbs, and a thick tail with moderate fins. It differs from other species in its genus with vertebral number with it having 13 trunk vertebrae, disproportionate lateral expansion of elements of the anterior cranial, lack of ossified orbitosphenoids and a arcuate lateral outline of the

mandible In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone i ...

. The Blanco blind salamander grows to up to 100.8mm in length.

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''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 proje ...

Cave salamanders Amphibians described in 1978 {{Plethodontidae-stub