The diamond darter (''Crystallaria cincotta'') is a species of freshwater ray-finned fish, a darter from the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

Etheostomatinae Etheosomatidae is a species rich subfamily of freshwater ray-finned fish, the members of which are commonly known as the darters. The subfamily is part of the family Percidae which also includes the perches, ruffes and pikeperches. The family i ...

, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is named for the sparkling light it reflects during nighttime collections. The diamond darter was first described in 2008 and is only the second known member of its genus, which also includes the crystal darter, ''C. asprella''. On July 26, 2013, the United States Fish and Wildlife Service formally designated the diamond darter as an endangered species under the Endangered Species Act of 1973.

Description

Diamond darters have 11-13

spine Spine or spinal may refer to: Science Biology * Vertebral column, also known as the backbone * Dendritic spine, a small membranous protrusion from a neuron's dendrite * Thorns, spines, and prickles, needle-like structures in plants * Spine (zoolog ...

s on their dorsal fins, and 11-15 soft rays. However, their

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

s do not have any spines at all, and only 11-13 soft rays. Adults are estimated to be 3-5 in long, with the largest specimen measuring 7.7 cm, roughly 3.0 in. Diamond darters bear a strong resemblance to crystal darters, their relatives. Both fishes are translucent, and have

olive The olive, botanical name ''Olea europaea'', meaning 'European olive' in Latin, is a species of small tree or shrub in the family Oleaceae, found traditionally in the Mediterranean Basin. When in shrub form, it is known as ''Olea europaea'' ...

-colored patterns on their bodies. Diamond darters differ in that they have a gape equal to or larger than the width of the base of their inter

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods. Structure and function Structure In actinopterygians, the pelvic fin consists of two en ...

s, which are shaped like sickles. They also have

blotch A stain is a discoloration that can be clearly distinguished from the surface, material, or medium it is found upon. They are caused by the chemical or physical interaction of two dissimilar materials. Accidental staining may make material, mat ...

es in front of the eyes that are separate from the orbital rim. The diamond darter has fewer dorsal spines and anal rays than the crystal darter. It also has fewer rows of

scale Scale or scales may refer to: Mathematics * Scale (descriptive set theory), an object defined on a set of points * Scale (ratio), the ratio of a linear dimension of a model to the corresponding dimension of the original * Scale factor, a number ...

s on the cheek (2), and

opercle The operculum is a series of bones found in bony fish and chimaeras that serves as a facial support structure and a protective covering for the gills; it is also used for respiration and feeding. Anatomy The opercular series contains four bon ...

(2).

Distribution

The diamond darter was described from specimens collected from the drainages of the

Cumberland Cumberland ( ) is a historic county in the far North West England. It covers part of the Lake District as well as the north Pennines and Solway Firth coast. Cumberland had an administrative function from the 12th century until 1974. From 19 ...

Elk The elk (''Cervus canadensis''), also known as the wapiti, is one of the largest species within the deer family, Cervidae, and one of the largest terrestrial mammals in its native range of North America and Central and East Asia. The common ...

, Green, and Muskingum Rivers, which are all part 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 ...

basin, from 1980 to 2005. Because of river

alteration Alteration(s) may refer to: * Alteration (music), the use of a neighboring pitch in the chromatic scale in place of its diatonic neighbor. ** Alteration, in the mensural notation used by renaissance music, the lengthening of a breve, semibreve or ...

s, and problems with water quality, the diamond darter's

range Range may refer to: Geography * Range (geographic), a chain of hills or mountains; a somewhat linear, complex mountainous or hilly area (cordillera, sierra) ** Mountain range, a group of mountains bordered by lowlands * Range, a term used to i ...

has become greatly diminished. As of 2008, the fish is only known to still live in the Elk River, West Virginia. The effect of the

2014 Elk River chemical spill The Elk River chemical spill occurred on January 9, 2014 when crude 4-Methylcyclohexanemethanol (MCHM) was released from a Freedom Industries facility into the Elk River, a tributary of the Kanawha River, in Charleston in the U.S. state of West ...

to the diamond darter is still unknown.

References

External links

practicalfishkeeping.co.ukwvutodayFishbase.org
{{Taxonbar, from=Q2425355 Diamond darter Elk River (West Virginia) Fish described in 2008 ESA endangered species Freshwater fish of the United States