Etia nguti
| Etia nguti | ||||||||||||
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Etia nguti |
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| Systematics | ||||||||||||
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| Scientific name of the tribe | ||||||||||||
| Etiini | ||||||||||||
| Schliewen & Stiassny , 2003 | ||||||||||||
| Scientific name of the genus | ||||||||||||
| Etia | ||||||||||||
| Schliewen & Stiassny, 2003 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Etia nguti | ||||||||||||
| Schliewen & Stiassny, 2003 |
Etia nguti is a species of African cichlid known only from the Mamfue River , a tributary of the Upper Cross River in the Cameroonian region of Sud-Ouest and a tributary near the village of Mboka. It is the only species in the genus Etia . The genus was named in honor of the late British ichthyologist Ethelwynn Trewavas , who researched the African cichlids for decades and was often called ET by her colleagues. Nguti is the place in the south-west of Cameroon, near which most of the type specimens examinedfor the first description were caught.
features
Etia nguti has a typical cichlid shape, but is slightly higher back than most species. The body height is 43.2 to 48% of the standard length , the greatest body height is at the beginning of the dorsal fin . The ventral side is slightly rounded, the caudal fin stalk high and short. The specimens in the type series were up to 7.3 cm in length, but three years after the initial description, a 13.3 cm male was caught. Etia nguti is covered with relatively large round scales from the eyes to the base of the caudal fin . The scales on the chest and stomach are not much smaller. On the head sides there are two to three rows of scales, gill covers and fore gill covers are covered with large, flattened scales. There are four rows of scales between the lateral line and the base of the dorsal fin, four to five scales between the pectoral and pelvic fins and 16 scales around the tail fin stalk. There are 26 to 27 scales along the sidelines. The lower sideline starts just below the end of the upper one, but does not extend any further. Etia nguti has a total of 25 vertebrae, 14 trunk and 11 tail vertebrae. Two well-formed supraneuralia (parts of the vertebrae) are connected to the first neural process . All other African cichlids, with the exception of Heterochromis and Tylochromis , have only one supraneuralia. The intestine forms three to four tightly wound loops and in the type specimens was filled with fine sand and detritus .
Skull and dentition
The large head occupies 32.3 to 35% of the standard length. The mouth is small and slightly underneath. This feature enables Etia nguti to be distinguished from all other high-backed cichlids ( Coptodon , Pelmatolapia , Thysochromis ) occurring in the same area . The upper lip is thick and has a characteristic fold that is absent from all other African cichlids. The lower lip is narrow. In specimens less than 45 mm in length, the teeth of the outer row of teeth are robust, slightly spade-shaped and three-pointed, in specimens more than 50 mm in length they are more two-pointed. Two to five three-pointed teeth remain in the back of the upper jaw, in the lower jaw all three-pointed teeth are replaced by two-pointed ones. In specimens of all sizes, there are two to three additional rows of teeth that are set with three-pointed teeth of the same size. On the lower branch of the first gill arch there are 14 to 16 closely spaced gill trap rays . There are also usually four to five epibranchial rays.
The apophysis (bone process) of the neurocranium for the upper pharyngeal jaw is, as in tilapia , formed solely by the parasphenoid . The lower pharyngeal jaw is small, relatively robust, and slightly wider than it is long. The front and middle area of the dentate pharyngeal plate is covered with small khukuri-like , sharp teeth at a large distance . The pharynx teeth are close together in the rear area. The back teeth are straight, double-pointed and relatively delicate. They have a recurved main tip and a significantly smaller tip below the main tip. On the ventral side (ventral side) of the lower pharyngeal jaw there is a well-developed median ridge. The mesethmoid, a skull bone, has no contact with the ploughshare . The tear bone has five openings.
Fins
The base of the dorsal fin extends over 55.2 to 59% of the standard length, with the much shorter anal fin it is 15.5 to 16.7%. In sexually mature males, the posterior rays of the dorsal and anal fin are elongated and extend to the base of the caudal fin. The pectoral fins are short and do not reach the anus . The first soft ray of the pelvic fins is long and in both sexes extends over the hard-rayed part of the anal fin.
- Fin formula : dorsal XV / 10, anal III / (7) -8.
The spine rays of the dorsal fin gradually increase in size up to the fourth ray and then decrease again by the 14th. The 15th spiked ray is significantly longer than the 14th, which leads to a clear dent in the dorsal fin.
coloring
Etia nguti is pale to golden-yellow in color, the mouth and neck are a little darker, more light brown, the belly light yellow. Each scale on the fuselage has a shimmering turquoise-blue spot that surrounds a central cream-colored point, creating rows of iridescent longitudinal bands. Behind the gill cover there is a large black-brown spot on a scaly field, another behind the pectoral fins. Depending on the mood, the spots are extended backwards along the middle of the body or towards the dorsal fin as a vertical band. The iris is golden yellow. The fins are transparent with numerous small turquoise dots on the soft-rayed sections of the dorsal and anal fin and on the middle area of the caudal fin.
Way of life
The Mamfue River at Nguti is about ten meters wide and a maximum of 1.5 meters deep. Juvenile Etia nguti live near the shore in very shallow water at a depth of only a few centimeters, full-grown specimens in deeper water between stones and sunken branches. Etia nguti feeds mainly on detritus , and plants and insects are also eaten.
Reproduction
Etia nguti is a larvophilic mouthbrooder . The German ichthyologist Jörg Freyhof observed the reproduction in the aquarium. The fish begin to reproduce at a length of 5 cm and spawn in a group of two males and three females on an open substrate. A female paratype had a total of 70 eggs in both ovaries . The eggs are dark orange and oval with the dimensions 2.0 × 2.5 mm. The parents protected and cleaned the eggs for about 60 hours. On the third day, the larvae hatch and are taken into the mouth by one of the parents, in most cases the female. After that, the relationship broke up and the parents separated. After 17 to 20 days, the fry are released from the mouth, but can return to their parents' mouth for protection in the event of danger and during the night.
Systematics
Etia nguti is systematically isolated and is assigned to a separate tribe, the Etiini. The species is basal to all other African cichlids with the exception of Heterochromis , Tylochromis , the Chromidotilapiini, Hemichromini and Pelmatochromini. The Haplotilapines, that is the large clade to which Etia is assigned, comprise mouth-brooding and substrate-brooding cichlids. The inner rows of teeth of the jaw teeth, which are covered with three-pointed teeth, are considered autapomorphy .
The following, simplified cladogram shows the relationships.
| Pseudocrenilabrinae |
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Danger
About a possible threat to etia nguti can International Union for Conservation of Nature and Natural Resources (IUCN) give no indication, as insufficient data are available ( Data Deficient ). Part of the distribution area is protected by the Nta Ali and Banyang Mbo forest reserves, the Banyang Mbo nature reserve and the expansion zone of the Korup National Park.
literature
- Ulrich K. Schliewen & Melanie LJ Stiassny : Etia nguti, a new genus and species of cichlid fish from the River Mamfue, Upper Cross River basin in Cameroon, West-Central Africa. Ichthyol. Explor. Freshwaters, Vol. 14, No. 1, pages 61–71, © 2003 by Verlag Or. Friedrich Pfeil, Munich, Germany - ISSN 0936-9902
Web links
- Etia nguti on Fishbase.org (English)
- Etia Nguti in the endangered Red List species the IUCN 2009. Posted by: Moelants, T., 2008. Accessed November 9, 2011th