COMPARATIVE CHROMOSOME MORPHOLOGY OF MALAGASY POISON FROGS (AMPHIBIA,RANIDAE, MANTELLA)

Karyotypes of 7 species of Mantella are described, and are used to dra w hypotheses on interspecific relationships. All studied species, M. b etsileo, M. viridis, M. laevigata, M. haraldmeieri, M. baroni, M. croc ea and M. aurantiaca, had a chromosome complement of 2n = 26, with 5 p airs of large chromosomes and 8 pairs of small chromosomes. We perform ed phenetic analysis of relative chromosome lengths (rl) and centromer indices (ci) as well as phylogenetic analysis of c-banding patterns a nd some distinct rl: and ci differences. All results indicated close r elationships of M. aurantiaca and M. crocea. By phenetic analysis, M. betsileo and M. viridis are closely grouped together, as are M. laevig ata and M. baroni. By phylogenetic analysis, M. haraldmeieri, M. betsi leo and M. viridis are the most basal species, whereas M. laevigata an d M. baroni sequentially split off from a clade leading to M. aurantia ca and M. crocea. These results are largely in agreement with other da ta sets. However, the position of M. laevigata, which is difficult to assess due to its large number of autapomorphies, and of M. haraldmeie ri, are partially conflicting with results from osteology, bioacoustic s, colouration and allozyme differentiation.