This species, besides being an aquarium fish favorites is found in tropical America. This species complex is widely distributed in lowland areas of South America east of the Andes, including the Amazon, Orinoco, and Paraña (Paraguay River) basins and various coastal drainages of the Guiana's (Géry 1977). The species grows to about 15 cm SL and is a food items for natives.

Leydig cells in Myleus ternetzi testes

Maurice Loir, Anne Margeridon and Chantal Cauty

INRA, Physiologie des Poissons, Campus de Beaulieu, 35042 Rennes Cedex, France

(Received 2 September 1988, Accepted 18 January 1989).

ABSTRACT

Males of Myleus ternetzi, at various maturation stages were netted in a French Guyana river. Testes were histologically and ultrastructurally analysed. Leydig cells were always present in large numbers. In mature or almost mature testes, they were characterized by a large spherical nucleus and an extensively developed smooth endoplasmic reticulum (SER) composed of very narrow tightly packed tubules. In regressed testes, most of the Leydig cells had a smaller nucleus with an irregular shape, a disorganized SER and the fine structure of the mitochondria was greatly affected. These changes would reflect different phases throughout a metabolic cycle in relation to spermatogenesis.

REFERENCES 

• THATCHER, V.E., SEY, O. & M. JÉGU, 1996.- New Amphistome (Trematoda) genera and species from Serrasalmid fishes, Myleus (Myloplus). Acta Zool. Acad. Scientia. Hung. 42(4): 261-270.

• JÉGU, M., 2001 Description complémentaire du type de Myloplus schulzei Ahl, 1938 (Characiformes: Characidae: Serrasalminae) et statut de l'espèce. Cybium, 25(4):

• JÉGU, M. & G.M. dos SANTOS, 2002. Révision du statut de Myleus setiger Müller & Troschel, 1844 et de Myleus knerii (Steindachner, 1881) (Teleostei: Characidae: Serrasalminae) avec une description complémentaire des deux espèces. Cybium. 26(1): 33-57.

• Géry, J., 1977. Characoids of the world.. T.F.H. Publications, Inc., N.J. pg: 672 (262-263), p: 665

• Froese, R. and D. Pauly. Editors. 2002. FishBase.World Wide Web electronic publication. www.fishbase.org 13 November 2002

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