Showing papers on "Mantella published in 1998"

Comparative osteology of Malagasy poison frogs of the genus Mantella (Amphibia: Ranidae: Mantellinae)

Abstract: Osteological features of all 13 valid species of the anuran genus Mantella, as well as three unnamed forms, were studied in order to assess intrageneric phylogeny and to find support for the monophyletic status of Mantella. Two characters present in all species (lack of maxillary teeth and a reduced zygomatic squamosal process) support the monophyly of the genus. A third character (anterior hyale process forming a complete arch) was found to be individually variable but presumably also constitutes a auta- pomorphy of Mantella. Four characters were found to be variable between but relatively constant within species: sternum shape, nasal and sphenethmoid size, and shape of anterior parasphenoid process. A cladistic analysis of the observed character states resulted in Mantella laevigata and the M. betsileo group representing the most basal lineages within the genus. All other species constitute a monophyletic group characterized by a large sphenethmoid and widely separated nasals; from this main lineage a second, monophyletic group splits off. It is characterized by an unforked sternum and contains M. nigricans, M. haraldmeieri, M. baroni, M. aff. baroni, M. cowani and M. bemhardi. This phylogeny is largely in agreement with available data on mating calls and colour pattern.

Comparative chromosome morphology of malagasy poison frogs (amphibia: ranidae : mantella)

Abstract: Karyotypes of 7 species of Mantella are described, and are used to draw hypotheses on interspecific relationships. All studied species, M. betsileo, M. viridis, M. laevigata, M. haraldmeieri, M. baroni, M. crocea and M. aurantiaca, had a chromosome complement of 2n = 26, with 5 pairs of large chromosomes and 8 pairs of small chromosomes. We performed phenetic analysis of relative chromosome lengths (rl) and centromer indices (ci) as well as phylogenetic analysis of c-banding patterns and some distinct rl and ci differences. All results indicated close relationships of M. aurantiaca and M. crocea. By phenetic analysis, M. betsileo and M. viridis are closely grouped together, as are M. laevigata and M. baroni. By phylogenetic analysis, M. haraldmeieri, M. betsileo and M. viridis are the most basal species, whereas M. laevigata and M. baroni sequentially split off from a clade leading to M. aurantiaca and M. crocea. These results are largely in agreement with other data sets. However, the position of M. laevigata, which is difficult to assess due to its large number of autapomorphie s, and of M. haraldmeieri, are partially conflicting with results from osteology, bioacoustics, colouration and allozyme differentiation.