Christmas darter
Christmas darter | |
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Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Perciformes |
Family: | Percidae |
Genus: | Etheostoma |
Species: | E. hopkinsi
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Binomial name | |
Etheostoma hopkinsi (Fowler, 1945)
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Synonyms[2] | |
Poecilichthys hopkinsi Fowler, 1945 |
The Christmas darter (Etheostoma hopkinsi) is a
The Christmas darter is closely related to the Savannah darter and the Christmas Eve or Hannukah darter, the latter of which is sometimes considered a subspecies of the Christmas darter rather than a species in its own right. The Christmas darter may hybridize with other darter species, though hybridization is hampered by behavioral and biological barriers. The Christmas darter is a common species in suitable habitat and the International Union for Conservation of Nature (IUCN) has assessed it as being of least concern for conservation purposes. In South Carolina, it is considered a conservation priority species, as it may be threatened in future by impoundment of rivers, siltation and deforestation.
Taxonomy
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Relationship of the Christmas darter with other members of its genus, based on a 2011 study[3] |
The Christmas darter was
The Christmas darter was traditionally considered part of the Oligocephalus subgenus, though a 2011 study found that the subgenus as defined was
Description
Darters have cylindrical bodies, large paired fins and poorly developed
The Christmas Eve darter is distinguishable from the Christmas darter by the presence of two dark, rectangular blotches near the top of its head. These blotches are either absent or faint in the Christmas darter. Additionally, the Christmas Eve darter and the Christmas darter differ in their number of lateral scales.[11] The Christmas Eve darter has 41–49 scales, the last 8–13 of which lack pores, while the Christmas darter has 40–47 scales, the last 2–11 of which lack pores.[12]
The Christmas darter can be separated from other members of its genus by a combination of the following traits; the lateral line (sensory organ along each side of the body) is straight; the branchiostegal membranes (structural membranes of the gill) on the gills are moderately connected; a frenum (membrane that attaches the upper lip to the snout) is attached to the upper lip; there are two spines on the anal fin.[11] The Christmas darter is most frequently confused with the Savannah darter, based on the similarities in their appearance and the overlap in their ranges.[7] The Savannah darter differs in having a pale stripe running along the spine and in having dorso-lateral dark streaks rather than dark dorsal saddles. The red stripes on the spinous dorsal fin is at the margin of the fin in the Savannah darter but in the middle in the Christmas darter.[13]
Distribution and habitat
![](http://upload.wikimedia.org/wikipedia/commons/thumb/d/d4/Altamaha_and_Rayonier.jpg/220px-Altamaha_and_Rayonier.jpg)
The Christmas darter is endemic to the states of Georgia and South Carolina in the southeastern United States. The nominate population is restricted to the Altamaha and Ogeechee River drainage basins in Georgia, both above and below the fall line, while the Christmas Eve darter occurs in the Savannah River catchment area, on the border between Georgia and South Carolina. Typical habitats include medium-sized and small rivers and creeks, riffles with rubble and coarse substrates, headwater creeks, and spring-fed streams with plentiful vegetation and sandy bottoms.[1]
Biology and ecology
The Christmas darter's biology is largely unknown.[11] It likely reproduces in March and April. Individuals become sexually mature by the end of their first year of life and have a maximum lifespan of two years. Its diet consists primarily of aquatic insects, though also includes other aquatic invertebrates.[7] It can hybridize with other darter species, though a hybridization study with it and the redband darter (E. luteovinctum) showed variation in hybrid inviability. Hybrid offspring from a Christmas darter female were often severely deformed, dying before hatching. The hybrid offspring of redband darter females had much higher likelihoods of successfully hatching. The major barrier to hybridization, however, is behavioral isolation, meaning that the Christmas darter has a strong preference for mating with members of its own species rather than hybridizing.[14]
Status
The Christmas darter is a common species and does not seem to be facing any particular threats. It occurs in numerous locations in the watersheds it occupies, and there is no reason to suspect that the overall population is decreasing. For these reasons, the International Union for Conservation of Nature has assessed its conservation status as "least concern".[1] As of 2015, it is considered a priority species in the state of South Carolina, along with 56 other freshwater fish.[15] Priority species were species that were not benefitting from federal conservation funding already, those rare or at-risk, those little known to science, or those that could be used as bioindicators.[16] Though many of the listed species of freshwater fish were noted to not be in danger of extinction, their inclusion was justified "if the goal is to maintain South Carolina's rich and diverse fish fauna".[15] Though not presently threatened with extinction, alteration of the watersheds it lives in could seriously reduce its range in the future.[12] Threats to the species could include deforestation, siltation and dams.[17]
See also
References
- ^ . Retrieved 19 November 2021.
- ^ a b Froese, Rainer; Pauly, Daniel (eds.) (2019). "Etheostoma hopkinsi" in FishBase. December 2019 version.
- ^ PMID 21775340.
- ISBN 9781422317914.
- ^ Mayasich, Joseph M.; Grandmaison, David (2004). Spotted Darter Status Assessment (PDF) (Report). US Fish & Wildlife Service. p. 1. NRRI/TR-2004-02.
- ^ Bailey, R. M.; Richards, W. J. (1963). "Status of Poecilichthys hopkinsi Fowler and Etheostoma trisella, new species, percid fishes from Alabama, Georgia, and South Carolina" (PDF). Occasional Papers of the Museum of Zoology (630): 4.
- ^ ISBN 9781570036804.
- ^ "Etheostoma binotatum". NCBI. Retrieved 6 January 2020.
- ^ "Etheostoma hopkinsi (Fowler, 1945)". ITIS. Retrieved 6 January 2020.
- ISBN 978-0-8203-2535-4.
- ^ ISBN 978-0-8203-2535-4.
- ^ ISBN 9780813165257.
- ISBN 978-0-8203-2535-4.
- S2CID 24837252.
- ^ a b South Carolina Department of Natural Resources. "Chapter 3: Taxonomic Groups" (PDF). SC SWAP 2015. p. 3-24.
- ^ South Carolina Department of Natural Resources (2005). "Chapter 2: South Carolina Priority Species" (PDF). Comprehensive Wildlife Conservation Strategy (Report). p. 2-1.
- ^ SCDNR Comprehensive Wildlife Conservation Strategy (2006). Species Account for Christmas Darter (PDF) (Report). p. 8 of 13. Retrieved 6 December 2019.