The Ozark cavefish, ''Troglichthys rosae'', is a small
subterranean freshwater fish 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 the
United States
The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...
. It has been listed as a threatened species in the US since 1984; the
IUCN
The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...
currently lists the species as Near Threatened, though it was previously listed as Vulnerable (VU D1+2 v2.3) between 1986 and 1996.
[ It is listed as Endangered and Threatened by the ]Missouri Department of Conservation
The Missouri Department of Conservation (MDC) and the Missouri Conservation Commission were created by Article IV Sections 40-42 of the Missouri Constitution, which were adopted by the voters of the state in 1936 as Amendment 4 to the constitut ...
.
Description
The Ozark cavefish is pinkish-white and reaches a maximum length of . The head is flattened, and it has a slightly protruding lower jaw.[ The fish has no ]pelvic fin
Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...
; the dorsal
Dorsal (from Latin ''dorsum'' ‘back’) may refer to:
* Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism
* Dorsal, positioned on top of an aircraft's fuselage
The fus ...
and anal fins are farther back than on most fish. It has only rudimentary eyes and no optic nerve
In neuroanatomy, the optic nerve, also known as the second cranial nerve, cranial nerve II, or simply CN II, is a paired cranial nerve that transmits visual system, visual information from the retina to the brain. In humans, the optic nerve i ...
. The Ozark cavefish lives only in caves. It has no pigmentation and has lost some unused characteristics. However, it is well adapted to a cave
Caves or caverns are natural voids under the Earth's Planetary surface, surface. Caves often form by the weathering of rock and often extend deep underground. Exogene caves are smaller openings that extend a relatively short distance undergrou ...
environment through well-developed sensory papillae. They feed primarily on microscopic organisms, as well as small crustaceans and salamander
Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...
larvae. Their reproductive rate is low compared to most other fish.
Habitat
Caves which have populations of the Ozark cavefish all have a relatively large source of nutrient
A nutrient is a substance used by an organism to survive, grow and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...
s, such as bat
Bats are flying mammals of the order Chiroptera (). With their forelimbs adapted as wings, they are the only mammals capable of true and sustained flight. Bats are more agile in flight than most birds, flying with their very long spread-out ...
guano
Guano (Spanish from ) is the accumulated excrement of seabirds or bats. Guano is a highly effective fertiliser due to the high content of nitrogen, phosphate, and potassium, all key nutrients essential for plant growth. Guano was also, to a le ...
or blown leaf litter.oxygen
Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...
content of ground water found in caves.
Distribution
The geographic distribution of Ozark cavefish consists of northeastern Oklahoma, northwestern Arkansas, and southwestern Missouri. The fish is native to the Springfield Plateau of the Ozark Highlands
The Ozark Highlands is a Level III ecoregion designated by the Environmental Protection Agency (EPA) in four U.S. states. Most of the region is within Missouri, with a part in Arkansas and small sections in Oklahoma and Kansas. It is the largest ...
. Currently, 15 caves in this area have verified populations. In Oklahoma, populations are known to occur in Delaware County. Historical records for Ottawa and Mayes Counties also indicate populations. Factors that have led to the decline of the Ozark cavefish include destruction of habitat, collecting of specimens, and disturbance by spelunkers.
See also
* Ozark Cavefish National Wildlife Refuge
The Ozark Cavefish National Wildlife Refuge is a 40-acre (16-ha) National Wildlife Refuge located in Lawrence County, Missouri, 20 mi (32 km) west of Springfield. The United States Fish and Wildlife Service acquired the land in 1991 t ...
References
External links
Endangered Species Guidesheet
Missouri Department of Conservation
Ghost Fish of the Ozarks
by Tracy Crede
{{Authority control
Amblyopsidae
Cave fish
Endemic fish of the United States
Freshwater fish of the Southeastern United States
Fauna of the Plains-Midwest (United States)
ESA threatened species
Fish described in 1898
Taxa named by Carl H. Eigenmann