Theraps irregularis
| Theraps irregularis | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name of the genus | ||||||||||||
| Theraps | ||||||||||||
| Günther , 1862 | ||||||||||||
| Scientific name of the species | ||||||||||||
| Theraps irregularis | ||||||||||||
| Günther, 1862 |
Theraps irregularis is a freshwater fish from the family of the tilapias , in the south of Mexico and in Guatemala in the upper flow-rich portions from Rio Usumacinta , Polochic River occurs, Rio and Rio Sarstún Dulce.
features
The species reaches a length of over 20 cm. Of all Central American cichlids, Theraps irregularis has the most elongated, streamlined physique and is therefore well adapted to the fast flowing water in its habitat. The number of vertebrae is correspondingly high. The species has 15 trunk vertebrae (abdominal vertebrae), 19, in rare cases 18 caudal vertebrae, which is the highest number of caudal vertebrae among all heroine cichlids, and 7 to 8 vertebrae in the very long caudal peduncle. The number of scales along the sidelines is also relatively high at 33. The specific epithet irregularis (= irregular) refers to the seven transverse bands on the sides of the body, some of which extend into the dorsal fin. As with Wajpamheros , Cincelichthys , Kihnichthys and Chuco , the fourth and fifth volumes are double. The throat and chest of adult specimens are slightly pink to bright red and the region above the base of the pectoral fin and some regions of the head are conspicuously blue. During the breeding season the basic color of Theraps irregularis is whitish to sky blue, only the underside of the head, the belly and the pelvic fins are black (typical breeding color of the Herichthyines ). The dorsal and anal fins are largely unscaled at their base. On the premaxillary and in the lower jaw, the teeth in the first row are two-pointed. All teeth are pointed, flattened on the labiolingual (lip and tongue side), but often blunt from the gnawing off of the growth. They are mostly vertical. Males become larger than females, have a more angular head with a slight hump forehead and their blue color is more intense. Females are darker overall.
Way of life
Theraps irregularis occurs exclusively in water with a lot of current, mostly with rocky or sandy subsoil, and feeds on algae and invertebrates that it finds in the growth. The fish are substrate spawners, preferring to spawn on sloping surfaces. The few eggs are roughly round and relatively large. They are looked after by the female while the male defends the territory. After the juveniles swim free, they are led by both parents.
Systematics
The species and genus were described in 1862 by the German ichthyologist Albert Günther , and the species has been assigned to the genus Cichlasoma in between . Other species of cichlids were later placed in the Theraps genus . Today, however, the genus is monotypical again , since a revision of the Central American cichlids found that it is not monophyletic with the other species. The other species that were temporarily assigned to Theraps belong today to the genera Chortiheros , Chuco , Paraneetroplus , Rheoheros , Talamancaheros . Theraps is the sister genus of Wajpamheros .
literature
- Horst Linke, Wolfgang Staek: American cichlids II, large cichlids. Tetra-Verlag, Bissendorf 1997, ISBN 3-89745-101-8 , page 412.
- Říčan, O., Piálek, L., Dragová, K. & Novák, J. (2016): Diversity and evolution of the Middle American cichlid fishes (Teleostei: Cichlidae) with revised classification . Vertebrate Zoology, 66 (1): 1-102.
Web links
- Theraps irregularis on Fishbase.org (English)