Eigenmannia virescens ';
General information
 
Eigenmannia virescens (Valenciennes, 1836)
 
 
Common nameGlass knifefish, Tuvira
Synonyms
Sternachus virescens Valenciennes, 1836
Sternatchus virescens Valenciennes, 1836
Sternopygus tumifrons Muller & Troschel, 1849
Sternopygus lineatus Muller & Troschel, 1849
Eigenmannia lineata (Muller & Troschel, 1849)
IUCN Red List status (2014)
Not Reported
Habitat
Freshwater
Systematics
Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Actinopterygii; Neopterygii; Teleostei; Ostariophysi; Gymnotiformes; Sternopygoidei; Sternopygidae.
Geographical distribution
Brazil; Argentina; Colombia; Peru; Venezuela; Ecuador; Uruguay; Guyana; Suriname; French Guiana
Occurrence Native: Brazil, Argentina, Colombia, Peru, Venezuela, Ecuador, Uruguay, Guyana, Suriname, French Guiana
Importance
Food
Remarks
Nil
Karyological information
Geographical area of study Tributaries of Mogi-Guaçu and Tietê river systems, Upper Parana´ river basin in Brazil.
Source of chromosomes
Kidney cells.
Number of specimens with sex
8 male, 25 female (Mogi-Guaçu river); 59 male, 47 female (Tietê river)
Diploid chromosome number
38
Karyotype formula
16m/sm+2st+20a
Fundamental arm number
-
Chromosome length
-
Sex chromosome
Mogi-Guaçu population showed undifferentiated sex chromosomes, while Tietê population with XX:XY sys
Chromosome staining/banding/FISH
Pericentromeric constitutive heterochromatin detected in all chromosomes, where pair no. 3 presents a heavy staining in the short arm. Chromosome pair 15 is NOR bearing at short arm. NORs brightly stained with CMA3 in both sexes.
Reference(s)
de Almeida-Toledo LF, Foresti F, Péquignot EV, Daniel-Silva MFZ (2001). XX:XY sex chromosome system with X heterochromatinization: an early stage of sex chromosome differentiation in the Neotropic electric eel Eigenmannia virescens. Cytogenet. Cell Genet., 95: 73–78.