| General information |
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Eigenmannia virescens (Valenciennes, 1836) |
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| Common name | Glass 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; native: Argentina; native: Colombia; native: Peru; native: Venezuela; native: Ecuador; native: Uruguay; native: Guyana; native: Suriname; native: French Guiana |
| Importance |
Food |
| Karyological information |
| Record 1 |
| Geographical area of study |
White-water rivers of the Eastern Amazon, America |
| Source of chromosomes |
Not reported |
| Number of specimens with sex |
15 |
| Diploid chromosome number |
38 |
| Karyotype formula |
14m/sm+24a males;15m/sm+23a females |
| Fundamental arm number |
52 for males & 53 for females |
| Chromosome length |
Not reported |
| Sex chromosome |
ZZ/ZW |
| Chromosome staining/banding/FISH |
C- banding revealed the presence of constitutive heterochromatin (CH) in the centromeric regions of all chromosomes; NOR was localized to the short arm of pair 15; DAPI fluorescence was found in the centromeric regions of all chromosome pairs; FISH with (TTAGGG)n telomeric probes did not show any evidence of an interstitial telomeric sequence (ITS). |
| Reference |
Fenocchio AS, Pastori MC, Roncati HA, Filho OM, Bertollo LAC (2003). A Cytogenetic Survey of the Fish Fauna from Argentina. Caryologia, 56(2): 197-204. |
| Record 2 |
| Geographical area of study |
Parana - Plata river basin, Argentina |
| Source of chromosomes |
Kidney |
| Number of specimens with sex |
Not reported |
| Diploid chromosome number |
40 |
| Karyotype formula |
Not reported |
| Fundamental arm number |
Not reported |
| Chromosome length |
Not reported |
| Sex chromosome |
Not reported |
| Chromosome staining/banding/FISH |
|
| Reference |
Fenocchio AS, Pastori MC, Roncati HA, Filho OM, Bertollo LAC (2003). A Cytogenetic Survey of the Fish Fauna from Argentina. Caryologia, 56(2): 197-204. |
| Record 3 |
| 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 |
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. |
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