A cytogenetic study was carried out on the chromosomes and the nuclear DNA content of the freshwater goby Economidichthys pygmaeus (Pisces, Gobiidae). The species is characterized by a 2n=46 karyotype consisting of 12 submetacentric and 11 subtelocentric chromosome pairs (NF=70). Major (45S) rDNA genes are terminal-centromeric located on the short arm of a single medium-small sized submetacentric pairas assessed by in situ hybridization, CMA3 staining, and Ag-NOR banding. The haploid (C-value) nuclear DNA content is 0.93±0.003 picograms. The cytogenetical data of Economidichthys pygmaeus were compared with those ones already available for other related gobies.
Keywords: Goby fish; fluorescent in situ hybridization; genome size; karyotype.