Retroculus

Retroculus lapidifer, drawing from Castelnau Expédition dans les parties de l' Amérique du Sud centrales, de Rio de Janeiro à Lima, Lima et de au Para: exécutée par ordre du gouvernement Français pendant les années 1843 à 1847 - Paris:. P. Bertrand, 1850-1857

Retroculus is a genus of South American cichlids. The scientific name refers to the eyes are far behind compared to other cichlids to ( Latin: retro = backward; oculus = eye).

Features

Retroculus species are 14 to 20 inches long. Their shape is similar to that of geophaginen cichlid Geophagus and Satanoperca. The head is large and brawny, thick-lipped mouth that tapers to. The eyes are set far back and up. The color of the fish is greenish to brownish. Head and trunk are patterned with shiny metallic dots and lines. In the back of the dorsal fin is a black spot. The caudal fin is in two distinct types of vertical strips in Retroculus lapidifer it is ungestreift. The fins are not extended in length, only the middle fin ray of the broad, short pectoral fins is prolonged. The swim bladder is regressed. Retroculus species can not float in the water thereby. Resting they are based with the pelvic fins on the bottom of the water. The number of scales in a median longitudinal row (MLR ) is 34 to 41, the belly scales are small.

Fins formula: Dorsal XIV-XVII/10-12, Anal III/6-7.

Plesiomorphies showing the earthiness of the genus, are the five sensory pores on the lower jaw, the seven sensory pores on the Vorkiemendeckel, lips, where African cichlids same and the numerous gill Reuse rays (10 to 15).

Way of life

Retroculus species live in clear water rivers of the highlands of Guiana and the Eastern Brazilian shield in rapids and areas with strong currents. They seek their food at the water bottom. Midges, caddis fly and mayfly larvae make up the largest part of their diet.

Reproduction

Procreation is little known. The Retroculus species during the breeding season dig a pit in the bottom of the water in which the eggs are laid. The pit can reach a diameter of half a meter and is covered after oviposition with larger pebbles to protect the eggs. Both parents participate in brood care. Observations in aquariums are not enough on the first day after oviposition expiration date, perhaps the eggs were then eaten by the parents.

System

Retroculus the cichlid subfamily Geophaginae was originally assigned. The Swedish ichthyologist Sven O. Kullander 1998, it is that takes the genre a basal position within the New World cichlids and placed the genus in its own subfamily, the retro Culinae.

Types and distribution

There are three scientifically described species that occur in the northeastern South America.

  • Retroculus lapidifer ( Castelnau, 1855), 20 cm, Southeast Amazonia ( catchment area of ​​the Rio Tocantins and Araguaia.
  • Retroculus septentrionalis Gosse, 1971, 20 cm, Oyapock between French Guiana and Brazil.
  • Retroculus xinguensis Gosse, 1971, 14 cm, Rio Xingu.

Two other species from the Rio Tapajós and the Rio Tocantins are still undescribed.

Swell

  • Side of the Swedish cichlid specialists Sven O. Kullander: Retroculus Eigenmann & Bray
  • Retroculus on Fishbase.org (English)
  • Claus Schaefer, Torsten Schroer: The great encyclopedia of fighting dogs, Ulmer Verlag, Stuttgart 2004, ISBN 3-8001-7497-9
Carl H. Eigenmann Fish fin Tocantins River
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