Chromosome and bands: comparative cytogenetics of the morphotypes of Ameerega trivittata (Anura: Dendrobatidae)

Ameerega trivittata is a widely distributed dendrobatid species with colour polymorphism for which only the diploid number, nucleolar organizer regions (NORs) and heterochromatic pattern are known. Here, we investigated the existence of cytogenetic structure in A. trivittata populations with different morphotypes. Four morphotypes and their geographical distributions were defined. All the individuals have 24 chromosomes and a similar heterochromatic pattern, the same location of telomeric regions and 5S rDNA. The NOR site was coincident with the 18S rDNA in pair 9, but some individuals presented an additional site in one of the homologues of pair 11. The highest variation was found in the microsatellite distribution patterns. Comparing the cytogenetic characters of the individuals, two groups were detected: (1) Tabatinga (morphotype B) and Benjamin Constant (morphotype A), and (2) Presidente Figueiredo and Tefé (morphotype C). The cytogenetic data appear to be correlated to the structure pattern of the morphotypes, and corroborate the dispersal routes proposed in the literature. This is the first study of population cytogenetics for the group. Our results provide a series of cytogenetic characters for A. trivittata and for Dendrobatidae for the first time and highlight the importance of considering cytogenetics in population research.