The Hoosier cavefish (''Amblyopsis hoosieri'') is a subterranean species of

blind fish A blind fish is a fish without functional eyes. Most blind fish species are found in dark habitats such as the deep ocean, deep river channels and underground. Blind fish species Agnathans *''Myxine glutinosa'' *''Myxine circifrons'' *'' Poli ...

from southern

Indiana Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th s ...

in the United States. Described in 2014, ''A. hoosieri'' was the first new species of amblyopsid cavefish to be discovered in 40 years.

Etymology

The specific name is derived from the word "

Hoosier Hoosier is the official demonym for the people of the U.S. state of Indiana. The origin of the term remains a matter of debate, but "Hoosier" was in general use by the 1840s, having been popularized by Richmond resident John Finley's 1833 poem "T ...

", the name for a resident of the state of

. The choice of the name was also influenced by the fact that Prosanta Chakrabarty, the senior author of the paper that first described the species, was a fan of the

Indiana Hoosiers The Indiana Hoosiers are the intercollegiate sports teams and players of Indiana University Bloomington, named after the colloquial term for people from the state of Indiana. The Hoosiers participate in NCAA Division I, Division I of the Nationa ...

college basketball In United States colleges, top-tier basketball is governed by collegiate athletic bodies including National Collegiate Athletic Association (NCAA), the National Association of Intercollegiate Athletics (NAIA), the United States Collegiate Athleti ...

team.

Discovery

During a 2013 study of '' Amblyopsis spelaea'', scientists found that the species was divided into two distinct evolutionary lineages: one north of the

Ohio River The Ohio River is a long river in the United States. It is located at the boundary of the Midwestern and Southern United States, flowing southwesterly from western Pennsylvania to its mouth on the Mississippi River at the southern tip of Illino ...

, in Indiana, and one south of the river, in

Kentucky Kentucky ( , ), officially the Commonwealth of Kentucky, is a state in the Southeastern region of the United States and one of the states of the Upper South. It borders Illinois, Indiana, and Ohio to the north; West Virginia and Virginia to ...

. The northern population was described as a new species in a 2014 paper published in the journal ''

ZooKeys ''ZooKeys'' is a peer-reviewed open access scientific journal covering zoological taxonomy, phylogeny, and biogeography. It was established in 2008 and the editor-in-chief is Terry Erwin (Smithsonian Institution). It is published by Pensoft Publ ...

'', making it the first new species of amblyopsid cavefish to have been discovered in the U.S. in 40 years.

Description

Average length is . The head makes up approximately one quarter of its total length. As typical of

cavefish Cavefish or cave fish is a generic term for fresh and brackish water fish adapted to life in caves and other underground habitats. Related terms are subterranean fish, troglomorphic fish, troglobitic fish, stygobitic fish, phreatic fish and hypog ...

, this species is blind. The lower jaw extends beyond the upper. The body is flattened dorsally, but robust, with short, rounded fins. The

anus The anus (Latin, 'ring' or 'circle') is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, the residual semi-solid waste that remains after food digestion, which, d ...

is located toward the front of the body, directly behind the gills. General coloration is pinkish-white, with red around the gills. The fins are transparent.

Reproduction and development

Breeding takes place between February and April, when the water levels are highest. Eggs are brooded in the females' gill cavity. After hatching, the females care for the young for 4–5 months. Individuals become

sexually mature Sexual maturity is the capability of an organism to reproduce. In humans it might be considered synonymous with adulthood, but here puberty is the name for the process of biological sexual maturation, while adulthood is based on cultural definitio ...

at 3–4 years of age. The species is suspected to have a lifespan of 12–15 years, but may live as long as 20 years.

Diet

The species feeds on

amphipods Amphipoda is an order of malacostracan crustaceans with no carapace and generally with laterally compressed bodies. Amphipods range in size from and are mostly detritivores or scavengers. There are more than 9,900 amphipod species so far descri ...

copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...

isopods Isopoda is an order of crustaceans that includes woodlice and their relatives. Isopods live in the sea, in fresh water, or on land. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed limbs on the thorax, an ...

, and

crayfish Crayfish are freshwater crustaceans belonging to the clade Astacidea, which also contains lobsters. In some locations, they are also known as crawfish, craydids, crawdaddies, crawdads, freshwater lobsters, mountain lobsters, rock lobsters, mu ...

. It is believed to be the

apex predator An apex predator, also known as a top predator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the highest trophic lev ...

in its environment.

Range and habitat

The subterranean ''A. hoosieri'' is distributed among 68 caves and 6 springs throughout Indiana, between the Ohio River and the East Fork of the White River. Its range is limited to those caves that were not covered by

glacier A glacier (; ) is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its Ablation#Glaciology, ablation over many years, often Century, centuries. It acquires dis ...

s during the

Pleistocene The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...

. The Hoosier cavefish is usually found in pools in slow-flowing cave streams, in water that ranges from more than deep to as shallow as . Other species from the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

have been observed to prefer large, deep pools.

Conservation status

The species is threatened by a number of factors: sedimentation from agriculture, human encroachment on its habitat, and groundwater pollution by

herbicide Herbicides (, ), also commonly known as weedkillers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page fo ...

pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and lampri ...

s, and

fertilizer A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...

. The species may also have been affected by over-collection of samples for scientific study during the late nineteenth and early twentieth centuries. Due to these factors, the authors recommended that the species be classified as vulnerable on the

IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is the world's most comprehensive inventory of the global conservation status of biol ...

. The Hoosier cavefish is known to occur in the protected

Spring Mill State Park Spring Mill State Park is a state park in the state of Indiana. The park is located to the south of Bloomington, about east of the city of Mitchell on Indiana Highway 60. It contains a settler's village, the Gus Grissom Memorial (with the ac ...

. The state of Indiana also has policies in place to protect species of ''

Amblyopsis ''Amblyopsis'' is a genus of small (up to long) fish in the family Amblyopsidae that are endemic to the central and eastern United States. Like other cavefish, they lack pigmentation and are blind. The most recently described species was in 2014 ...

''.

References

External links

* {{Taxonbar, from=Q18979805 Amblyopsidae Freshwater fish of the United States Cave fish Fish described in 2014 Taxa named by Prosanta Chakrabarty