''Stygoparnus'' is a

monotypic genus In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

''Stygoparnus''.
BugGuide.net of

beetles Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...

containing the single species ''Stygoparnus comalensis'', which is known by the common name Comal Springs dryopid beetle. This rare beetle 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 elsew ...

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

in the United States, where it is known from two springs. It is a federally listed

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

of the United States. The Comal Springs dryopid beetle was first collected in 1987 and described as a new species in 1992. This beetle is 3 to 3.7 millimeters long. A subterranean species, it has

vestigial Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on co ...

eyes and faint

pigmentation A pigment is a colored material that is completely or nearly insoluble in water. In contrast, dyes are typically soluble, at least at some stage in their use. Generally dyes are often organic compounds whereas pigments are often inorganic compo ...

. It is the only known aquatic species in its family. It is known from Comal Springs in

Comal County Comal County ( ) is a county located on the Edwards Plateau in the U.S. state of Texas. As of the 2020 census, its population was 161,501. Comal County is known for its rich German-Texan and European history. Its county seat is New Braunfels. ...

, and Fern Bank Springs in

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 ...

. Though it lives in springs, the beetle does not swim and perhaps lives in air pockets in the caves. Little is known about the life history of the beetle because the

karst Karst is a topography formed from the dissolution of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves. It has also been documented for more weathering-resistant ro ...

cave habitat is difficult to explore.USFWS
Final rule to list three aquatic invertebrates in Comal and Hays Counties, TX, as endangered.
''Federal Register'' December 18, 1997. The beetle lives in one spring which is fed by 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 ...

, and one spring that has an unknown water source. The Edwards Aquifer has long been tapped for its water, which is used for many purposes, such as

irrigation Irrigation (also referred to as watering) is the practice of applying controlled amounts of water to land to help grow Crop, crops, Landscape plant, landscape plants, and Lawn, lawns. Irrigation has been a key aspect of agriculture for over 5,00 ...

. The primary threat to the species and other rare local endemic animals such as Peck's cave amphipod is the loss of the water source which feeds the springs.USFWS
Designation of critical habitat for the Peck's Cave Amphipod, Comal Springs Dryopid Beetle, and Comal Springs Riffle Beetle; Final rule.
''Federal Register'' July 17, 2007.

References

External links

''Stygoparnus comalensis''.
The Nature Conservancy.

References

External links

Further reading