''Texella reyesi'' is a rare species of

arachnid Arachnida () is a class of joint-legged invertebrate animals (arthropods), in the subphylum Chelicerata. Arachnida includes, among others, spiders, scorpions, ticks, mites, pseudoscorpions, harvestmen, camel spiders, whip spiders and vinegaroon ...

known by the common name Bone Cave harvestman. 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 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 lives 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 ...

caves in Travis and Williamson Counties. It is threatened by the loss of its habitat. 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.USFWS
Coffin Cave Mold Beetle (''Batrisodes texanus'') and the Bone Cave Harvestman (''Texella reyesi'') determined to be endangered.
''Federal Register'' August 18, 1993. Specimens of this

harvestman The Opiliones (formerly Phalangida) are an order of arachnids colloquially known as harvestmen, harvesters, harvest spiders, or daddy longlegs. , over 6,650 species of harvestmen have been discovered worldwide, although the total number of ext ...

were once included as members of ''

Texella reddelli ''Texella reddelli'', the Bee Creek cave harvestman, is a rare species of troglobitic harvestman that was added to the United States endangered species list in 1988, at the same time as six other species native to the karst ecosystem in Travis ...

'', and the two species are closely related. This harvestman was described as a new species in 1992.Ubick, D. and T. S. Briggs. (1992). The harvestman family Phalangodidae. 3. Revision of ''Texella'' Goodnight and Goodnight (Opiliones: Laniatores). ''Texas Mem. Mus., Speleol. Monogr.'' 3:155-240. Texella reyesi pair IMG 4206

This harvestman is eyeless and pale orange in color. It is 1.4 to 2.7 millimeters long and has long legs.''Texella reyesi''.
Texas Parks & Wildlife. The lack of eyes and body pigment and the long legs are

adaptation In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the po ...

s for life as a

troglobite A troglobite (or, formally, troglobiont) is an animal species, or population of a species, strictly bound to underground habitats, such as caves. These are separate from species that mainly live in above-ground habitats but are also able to live u ...

, an animal which spends its whole life in dark caves.USFWS
''Texella reyesi'' Five-year Review.
December 2009. It consumes

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s. It is sensitive to

humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity depe ...

and cannot tolerate dry conditions. During dry times it seeks the most moist corners of its cave environment. This animal is known from 168

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 ...

caves on the

Edwards Plateau The Edwards Plateau is a geographic region at the crossroads of Central Texas, Central, South Texas, South, and West Texas. It is bounded by the Balcones Fault to the south and east, the Llano Uplift and the Llano Estacado to the north, and the ...

of Texas. This and other species that live in these cave networks are threatened by a number of processes. The worst threat is the outright loss of its cave habitat, which is destroyed as the land is consumed for urban development. Caves are also altered and

polluted Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the ...

so that they cannot support this and other species.

Controversy

A Texas rancher, John Yearwood, and others has filed a lawsuit against the U.S. Fish and Wildlife Service to have the Bone Cave harvestman delisted from the endangered list. The arachnids are found on his property and he said their presence and their status is preventing him from developing the land.

References

{{Taxonbar, from=Q2802726 Harvestmen Cave arachnids Endemic fauna of Texas Animals described in 1992