Gymnocrotaphus is a monospecific genus of marine ray-finned fish belonging to the family Sparidae, which includes the seabreams and porgies. The only species in the genus is the Gymnocrotophus curvidens, the Janbruin, an endemic to the coasts of South Africa.
| Gymnocrotaphus | |
|---|---|
| |
| Janbruin at Whittle Rock | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Spariformes |
| Family: | Sparidae |
| Genus: | Gymnocrotaphus Günther, 1859 |
| Species: | G. curvidens
|
| Binomial name | |
| Gymnocrotaphus curvidens Günther, 1859
| |
Taxonomy edit
Gymnocrotaphus was first proposed as a monospecific genus in 1859 by the German-bprn British herpetologist and ichthyologist Albert Günther[2] when he described its only species, Gymnocrotaphus curvidens, from the Cape of Good Hope.[3] This taxon is placed in the family Sparidae within the order Spariformes by the 5th edition of Fishes of the World.[4] Some authorities classify this genus in the subfamily Boopsinae,[5] but the 5th edition of Fishes of the World does not recognise subfamilies within the Sparidae.[4]
Etymology edit
Gymnocrotaphus combines gymnos, meaning naked, and crotaphus meaning "cheek", a reference to the lack of scales on the cheeks of this species. The specific name, curvidens, means "curved teeth", an allusion to the curved incisor-like teeth in rows in the front of each jaw.[6]
Description edit
Gymnocrotaphus has a naked head, except for some scales on the gill cover. There is a band of curved incisor-like teeth in each jaw with a band of smaller conical teeth inside this and the very small molar-like teeth inside those. There are 10 spines and 11 or 12 soft rays supporting the dorsal fin while the anal fin is supported by 3 spines and 9 or 10 soft rays. The body is rather plump and deep, its depth fitting into its standard length 2.3 times. The dorsal profile of the headis concave in front of the eyes, and just above the eyes too. In life the colour of the body is coppery brown with a bluish grey head and blue eyes. Along exh scale row there are orange lines.[7] This species has a maximum published total length of 50 cm (20 in).[8]
Distribution and habitat edit
Gymnoctotaphus is endemic to the southeastern Atlantic and southwestern Indian Oceans where it is endemic to the coasts of South Africa from False Bay in the [{Western Cape to Port St. Johns in the Eastern Cape.[7] This species is found at depths between 1 and 80 m (3 ft 3 in and 262 ft 6 in) on shallow reefs.[1]
Biology edit
Gymnocrotaphus is an omnivorous, feeding on sea squirts, bryozoans, polychaetes, algae and crustaceans. It is a sedentary species which tends to stay close to the reef in crevices and overhangs.[9][10][11] Little is known about the biology of this species but it is thought it may be hermaphroditic.[1]
Economic importance edit
Caught by shore anglers and spearfishers, with bag limit, prohibited for sale.[9]
Conservation status edit
IUCN Status: Least concern. This species is considered to be effectively protected by no-take MPAs over its entire distributional range.[9]
References edit
- ^ a b c Mann, B.Q.; Buxton, C.D.; Russell, B.; Pollard, D. & Carpenter, K.E. (2014). "Gymnocrotaphus curvidens". IUCN Red List of Threatened Species. 2014: e.T170193A1290621. doi:10.2305/IUCN.UK.2014-3.RLTS.T170193A1290621.en. Retrieved 28 January 2024.
- ^ Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Genera in the family Sparidae". Catalog of Fishes. California Academy of Sciences. Retrieved 28 January 2024.
- ^ Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Species in the genus Gymnocrotaphus". Catalog of Fishes. California Academy of Sciences. Retrieved 28 January 2024.
- ^ a b Nelson, J.S.; Grande, T.C.; Wilson, M.V.H. (2016). Fishes of the World (5th ed.). Hoboken, NJ: John Wiley & Sons. pp. 502–506. doi:10.1002/9781119174844. ISBN 978-1-118-34233-6. LCCN 2015037522. OCLC 951899884. OL 25909650M.
- ^ Parenti, P. (2019). "An annotated checklist of the fishes of the family Sparidae". FishTaxa. 4 (2): 47–98.
- ^ Christopher Scharpf (12 January 2024). "Order ACANTHURIFORMES (part 6): Families GERREIDAE, LETHRINIDAE, NEMIPTERIDAE and SPARIDAE". The ETYFish Project Fish Name Etymology Database. Christopher Scharpf. Retrieved 28 January 2024.
- ^ a b Yukio Iwatsuki and Phillip C Heemstra (2022). "Family Sparidae". In Phillip C Heemstra; Elaine Heemstra; David A Ebert; Wouter Holleman; and John E Randall (eds.). Coastal Fishes of the Western Indian Ocean (PDF). Vol. 3. South African Institute for Aquatic Biodiversity. pp. 284–315. ISBN 978-1-990951-32-9.
- ^ Froese, Rainer; Pauly, Daniel (eds.) (2023). "Gymnocrotaphus curvidens" in FishBase. October 2023 version.
- ^ a b c "Red List of South African Species". SANBI. December 2000. Retrieved 24 August 2023.
- ^ Branch, G.M.; Branch, M.L.; Griffiths, C.L.; Beckley, L.E. (2010). Two Oceans: a guide to the marine life of southern Africa (2nd ed.). Cape Town: Struik Nature. ISBN 978 1 77007 772 0.
- ^ Jones, Georgina (2008). A field guide to the marine animals of the Cape Peninsula. Cape Town: SURG. ISBN 978-0-620-41639-9.