Chromosome Diversity and Evolution of the Endemic Malagasy Velvet Geckos of the Genus (Reptilia, Gekkonidae).

We performed a molecular and phylogenetic analysis and a comparative cytogenetic study with standard karyotyping, silver staining (Ag-NOR) and sequential C-banding + Giemsa, + fluorochromes on several samples. The phylogenetic inference retrieved two main clades, the first comprises , and , while the second includes , and . The available samples of form two different clades (here named clade A and clade B), which probably deserve a taxonomic re-evaluation. We found a karyological variability in in terms of chromosome number (2n = 40-42), morphology, location of NORs, and heterochromatin distribution pattern. and clade A and B showed a karyotype of 2n = 40 mostly telocentric chromosomes. Pairs 1 and 6 were metacentric in clade A and B, while pair 1 was composed of subtelocentric/submetacentric elements in In contrast, displayed a karyotype with 2n = 42 only telocentric chromosomes. NORs were on the first chromosome pair in , and on the second pair in . Adding our data to those available from the literature on evolutionarily related species, we highlight that the chromosome diversification in the genus probably proceeded towards a progressive reduction in the chromosome number and the formation of metacentric elements.