The peculiar herpetofauna of some Tsaratanana rainforests and its affinities with Manongarivo and other massifs and forests of northern Madagascar

Abstract

Amphibians and reptiles were surveyed at several rainforest sites on the Tsaratanana Massif and in the nearby Manongarivo Massif, NW Madagascar. Visual methods and pitfalls led to the discovery of 30 amphibian and 23 reptile species at Tsaratanana, and 30 amphibian and 17 reptile species at Manongarivo. The herpetofauna present at the investigated sites turned out to be composed (1) of typical elements of Madagascar's eastern rainforests, (2) of species widely distributed at low altitudes of the northwest, (3) of species typical for rainforests of the northeast and north (Montagne d'Ambre), and (4) of a rather large proportion of possible endemics. Beside many still undescribed species, we found some species of considerable biogeographic interest, such as the snake Pseudoxyrhopus ambreensis and the treefrog Boophis blommersae at Tsaratanana, previously known only from Montagne d'Ambre, which emphasizes a biogeographical link to this northernmost massif. At Manongarivo we also found one still unidentified species of leaf‐axil dwelling mantellid frog of the subgenus Pandanusicola, representing the first record of this subgenus from northwestern rainforests. Comparisons of mitochondrial DNA sequences of some selected amphibian species indicate that the populations from Tsaratanana and Manongarivo show no or only a slight differentiation between the two massifs but are often strongly different from conspecific populations, or from their closest relatives, in other regions of Madagascar. Conservation at Tsaratanana should, as a priority, include an increase of field surveys and an integration of local people in the management planning of this huge massif.