Texella reyesi
Encyclopedia
Texella reyesi is a rare species of arachnid
known by the common name Bone Cave harvestman. It is endemic to Texas
in the United States, where it lives in subterranean limestone
caves in Travis and Williamson Counties
. It is threatened by the loss of its habitat. It is a federally listed endangered species
of the United States.
Specimens of this harvestman
were once included as members of Texella reddelli
, and the two species are closely related. This harvestman was described as a new species in 1992.
This harvestman is eyeless and pale orange in color. It is 1.4 to 2.7 millimeters long and has long legs. The lack of eyes and body pigment and the long legs are adaptation
s for life as a troglobite
, an animal which spends its whole life in dark caves. It consumes invertebrate
s. It is sensitive to humidity
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
caves on the Edwards Plateau
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
so that they cannot support this and other species.
Arachnid
Arachnids are a class of joint-legged invertebrate animals in the subphylum Chelicerata. All arachnids have eight legs, although in some species the front pair may convert to a sensory function. The term is derived from the Greek words , meaning "spider".Almost all extant arachnids are terrestrial...
known by the common name Bone Cave harvestman. It is endemic to Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
in the United States, where it lives in subterranean limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
caves in Travis and Williamson Counties
Williamson County
Williamson County is the name of three counties in the United States:* Williamson County, Illinois* Williamson County, Tennessee* Williamson County, Texas...
. It is threatened by the loss of its habitat. It is a federally listed endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
of the United States.
Specimens of this harvestman
Opiliones
Opiliones are an order of arachnids commonly known as harvestmen. , over 6,400 species of harvestmen have been discovered worldwide, although the real number of extant species may exceed 10,000. The order Opiliones can be divided into four suborders: Cyphophthalmi, Eupnoi, Dyspnoi and Laniatores...
were once included as members of Texella reddelli
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 County and Williamson County, Texas, USA...
, and the two species are closely related. This harvestman was described as a new species in 1992.
This harvestman is eyeless and pale orange in color. It is 1.4 to 2.7 millimeters long and has long legs. The lack of eyes and body pigment and the long legs are adaptation
Adaptation
An adaptation in biology is a trait with a current functional role in the life history of an organism that is maintained and evolved by means of natural selection. An adaptation refers to both the current state of being adapted and to the dynamic evolutionary process that leads to the adaptation....
s for life as a troglobite
Troglobite
Troglobites are small cave-dwelling animals that have adapted to their dark surroundings. Troglobite species include spiders, insects, fish and others. They live permanently underground and cannot survive outside the cave environment. Troglobite adaptations and characteristics include a heightened...
, an animal which spends its whole life in dark caves. It consumes invertebrate
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s. It is sensitive to humidity
Humidity
Humidity is a term for the amount of water vapor in the air, and can refer to any one of several measurements of humidity. Formally, humid air is not "moist air" but a mixture of water vapor and other constituents of air, and humidity is defined in terms of the water content of this mixture,...
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
Kilometer-square Area Radio Synthesis Telescope is a Chinese telescope project to which FAST is a forerunner. KARST is a set of large spherical reflectors on karst landforms, which are bowlshaped limestone sinkholes named after the Kras region in Slovenia and Northern Italy. It will consist of...
caves on the Edwards Plateau
Edwards Plateau
The Edwards Plateau is a region of west-central Texas which is bounded by the Balcones Fault to the south and east, the Llano Uplift and the Llano Estacado to the north, and the Pecos River and Chihuahuan Desert to the west. San Angelo, Austin, San Antonio and Del Rio roughly outline the area...
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
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
so that they cannot support this and other species.