The South American characin genus Erythrinus may actually be a species-complex, says a new molecular study published this month.
A team of scientists from the Federal University of Sao Carlos in Sao Paulo, Brazil, studied the chromosomes of Erythrinus erythrinus (a cytogenetic technique known as karyotyping) and report their findings in the latest issue of the journal Heredity.
The scientists studied the chromosomes of E. erythrinus from five separate locations in Brazil and one in Peru and found distinct differences in the chromosomes of the fish. Some populations had extra chromosomes, others had male-female differences, while others did not.
The team says that Erythrinus populations show "fixed and exclusive" chromosomal features which suggest that the genus contains a complex of related species.
For more details see: Bertollo LA, Oliveira C, Molina WF, Margarido VP, Fontes MS, Pastori MC, Falcao Jd JN, Fenocchio AS. (2004) - Chromosome evolution in the erythrinid fish, Erythrinus erythrinus (Teleostei: Characiformes). Heredity. 2004 Aug;93(2):228-33.