Bioacoustics of Megasoma bollei

Remarks . Megasoma bollei was described by Dechambre (2006) who highlighted characteristics of the clypeus (triangular, short, acute) and mandibles (projected beyond the clypeus) to accommodate the species in Gibboryctes . However, the characters used by Dechambre (2006) are insufficient to justify the position within the genus, since Endrödi (1974) defined it by many more attributes, such as absence of sexual dimorphism; frons with a transverse tubercle in both sexes; bidentate mandibles with lobed teeth strongly produced; pronotum without horns or tubercles, only with a shallow concavity in both sexes; prosternal process short; tergite 7 (=propygidium) lacking stridulatory area; quadridentate protibiae; and protarsi not thickened in males. These characters are incompatible with those observed in M. bollei . Rather, the species is morphologically associated with the aspects used to define Megasoma ( Hardy 1972 , Lachaume 1985 , Morón 2005 , Prandi et al . 2020 ): conspicuous sexual dimorphism marked by the presence of a bifurcate, short horn on the male head ( Fig. 2A ), while females have only two small tubercles ( Fig. 2D ); male pronotum with an anterior tubercle ( Fig. 1E ), tubercle absent in females ( Fig. 1G ); mandibles without teeth ( Fig. 2A ); tergite 7 lacking stridulatory apparatus; tridentate protibiae ( Fig. 2A ); and cylindrical protarsomeres (1–5 combined subequal to protibial length) ( Fig. 2D ). The length of the protarsomeres relative to the protibial length supports placement of M. bollei in Dynastini rather than Oryctini ( Endrödi 1976 , 1985 ). Nineteen species are now included in the genus Megasoma ( Morón 2005 ; Prandi et al . 2020 ).