Chromosome Data and Karyotype Diversity of Anurans from Madagascar: Half a Century After the First Broad Cytosystematic Approach.

Madagascar is one of the world's most prominent biodiversity hotspots and is characterized by exceptionally high amphibian diversity, with 429 currently described, mostly endemic species. However, cytogenetic research on Malagasy amphibians has been conducted only intermittently over the years. Previous studies, mostly using conventional staining and banding methods and often confined to single taxa or isolated families, have provided only partial insights into the karyotype evolution and genome organization of the major Malagasy clades. In this contribution, we present the first comprehensive synthesis of all available cytogenetic data on Malagasy anurans, including chromosome number and morphology, heterochromatin distribution, and chromosomal markers across the major endemic Malagasy families. By integrating and comparing results from decades of scattered studies, this review reveals consistent patterns of chromosomal diversification and identifies evolutionary trends associated with speciation and adaptive radiation in Malagasy amphibians. Overall, native Malagasy amphibian species can be subdivided into two main karyotype groups: the first includes karyotypes with only biarmed chromosomes (