Voice of a giant: bioacoustic data for Mantidactylus guttulatus (Amphibia: Mantellidae)

The endemic radiation of mantellid frogs from Madagascar (Richards et al., 2000; Vences and Glaw, 2001; Vences et al., 2002) includes a large diversity in terms of morphological and ecological adaptations (Blommers-Schloesser and Blanc, 1991). The smallest species have adult snout-vent lengths of only 11-16 mm, while the two largest species reach more than 100 mm: Mantidactylus guttulatus (up to 120 mm) and M. grandidieri (up to 108 mm). In the large genus Mantidactylus (currently about 75 species in 12 subgenera), M. guttulatus is the type species of the subgenus and genus Mantidactylus (Andreone, in press). These giant Malagasy frogs are widespread in the rainforests of the island and are relative easy to observe. They are quite regularly consumed for food (under the local name of "radakabe" or "radaka") and can be seen for sale on markets. However, their ecology is so far largely unknown. They are semiaquatic species living in small to medium-sized brooks and torrents but their reproductive behaviour, eggs, tadpoles and vocalizations remained undescribed except for the observation of large oocytes (4- 5 mm) in dissected gravid females. Glaw and Vences (1994) described distress calls of M. grandidieri and hypothesized that, regarding advertisement calls, M. guttulatus may be a non-calling species. In this paper we describe for the first time the advertisement calls of a representative of the subgenus Mantidactylus.