Garra is a genus of fish in the family Cyprinidae. These fish are one example of the "log suckers", sucker-mouthed barbs and other cyprinids commonly kept in aquaria to keep down algae. The doctor fish of Anatolia and the Middle East belongs in this genus.[1] The majority of the more than 160 species of garras are native to Asia, but about one-fifth of the species are from Africa (East, Middle and West, but by far the highest species richness in Ethiopia).[2][3]

Garra
Doctor fish (Garra rufa)
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Cypriniformes
Family: Cyprinidae
Subfamily: Labeoninae
Genus: Garra
F. Hamilton, 1822
Type species
Cyprinus (Garra) lamta
F. Hamilton, 1822
Synonyms

Ageneiogarra Garman, 1912
Brachygramma Day, 1865
Discognathichthys Bleeker, 1860
Discognathus Heckel, 1843
Hemigrammocapoeta Pellegrin, 1927
Iranocypris Bruun & Kaiser, 1944
Lissorhynchus Bleeker, 1860
Mayoa Day, 1870
Phreatichthys Vinciguerra, 1924
Platycara McClelland, 1838
Tylognathoides Tortonese, 1938 Typhlogarra Trevawas, 1955

The genus was established by Francis Buchanan-Hamilton in 1822 as a subgenus of Cyprinus (which at that time was a "basket genus" for carp-like cyprinids); though it didn't lead to an act of him to designate a type species by the time. However, as no other garras except the newly discovered G. lamta were known to science in 1822, this was designated as the type species by Pieter Bleeker in 1863. The garras and their closest relatives are sometimes placed in a subfamily Garrinae, but this seems hardly warranted. More often, this group is included in the Labeoninae, or together with these in the Cyprininae. In the former case, the garras are members of the labeonine tribe Garrini, in the latter they are in the subtribe Garraina of tribe Labeonini. The genus Discogobio is a close relative.[3]

Description and ecology

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These species are slim cyprinids with a flat belly and a sucking mouth; their shape indicates that they are at least in tendency rheophilic. They are distinguished from other cyprinids by a combination of features: As in their closest relatives, their lower lip is expanded at its posterior rim to form a round or oval sucking pad, the vomero-palatine organ is much reduced or completely lost, the pectoral fins have at least the first two rays enlarged and usually unbranched, the supraethmoid is wider than long when seen from above, and the cleithrum is narrow and elongated to the front.[3]

From other Garrini (or Garraina), the genus Garra can be distinguished as follows: their pharyngeal teeth are arranged in three rows (like 2,4,5–5,4,2), the dorsal fin has 10-11 rays and starts slightly anterior to the pelvic fins, while the anal fin starts well behind the pelvic fins and has 8-9 rays. As far as is known, the diploid karyotype of garras is 2n = 50.[3]

Garras are not or barely noticeably sexually dimorphic and generally cryptically coloured benthic freshwater fish. Six species in the genus (G. andruzzii, G. dunsirei, G. lorestanensis, G. tashanensis, G. typhlops and some populations of G. barreimiae) are cave-adapted, lacking pigmentation and/or eyes.[4][5][6][7] Garras are omnivorous, eating alga, plankton and small invertebrates that they suck off substrate like rocks or logs. The food is scraped off with the sharp keratinized borders of the jaws and ingested via suction, created by contracting and relaxing the buccopharynx. As typical for Cypriniformes, the garras lack a stomach entirely, their oesophagus leading directly to the sphincter of the intestine. Different Garra species eat animal and vegetable matter in different proportions, which can – as typical for vertebrates – usually be recognized by the length of their intestine compared to related species: more herbivorous species have a longer intestine. Indeed, intestinal length in this genus is remarkably constant within species and varies a lot between species, meaning that it is useful to distinguish species and that dietary shifts have played a significant role in the evolution of garras.[3]

When the females are ready to spawn, they are markedly plump and swollen; the ripe roe may fill almost four-fifths of their body cavity. The testicles of reproductive males are large too. The average Garra egg is 1.77 mm in diameter and a clutch contains several hundred eggs – up to a thousand or so in large females. The breeding behaviour is generally not well known and breeding is not often achieved in the aquarium; presumably, like many of their relatives they migrate upstream or (if they otherwise inhabit lakes) into the rivers to spawn.[3]

Species

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These are the currently recognized species in this genus:

 
Garra blanfordii
 
Garra makiensis

References

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  1. ^ Froese, Rainer; Pauly, Daniel (eds.). "Garra rufa". FishBase. August 2017 version.
  2. ^ Froese, Rainer; Pauly, Daniel (eds.). "Species in genus Garra". FishBase. March 2017 version.
  3. ^ a b c d e f Stiassny, M.L.J.; Getahun, A. (2007). "An overview of labeonin relationships and the phylogenetic placement of the Afro-Asian genus Garra Hamilton, 1922 (Teleostei: Cyprinidae), with the description of five new species of Garra from Ethiopia, and a key to all African species" (PDF). Zoological Journal of the Linnean Society. 150 (1): 41–83. doi:10.1111/j.1096-3642.2007.00281.x. Archived from the original (PDF) on 2008-12-02.
  4. ^ Mousavi-Sabet, H.; Eagderi, S. (2016). "Garra lorestanensis, a new cave fish from the Tigris River drainage with remarks on the subterranean fishes in Iran (Teleostei: Cyprinidae)". FishTaxa. 1 (1): 45–54.
  5. ^ Farashi, A.; Kaboli, M.; Rezaei, H.R.; Naghavi, M.R.; Rahimian, H.; Coad, B.W. (2014). "Reassessment of the taxonomic position of Iranocypris typhlops Bruun & Kaiser, 1944 (Actinopterygii, Cyprinidae)". ZooKeys (374): 69–77.
  6. ^ Romero, A., ed. (2001). The Biology of Hypogean Fishes. Developments in Environmental Biology of Fishes. p. 17. ISBN 978-1402000768.
  7. ^ MOUSAVI-SABET, Hamed; et al. (2016). "Tashan Cave a New Cave Fish Locality for Iran; and Garra tashanensis, a New Blind Species from the Tigris River Drainage (Teleostei: Cyprinidae)". Fishtaxa. 1 (3): 133–148.