Extremely divergent song types in the genus Aerotegmina Hemp (Orthoptera: Tettigoniidae: Hexacentrinae) and the description of a new species from the Eastern Arc Mountains of Tanzania (East Africa)

The genus Aerotegmina comprises a group of African canopy-dwelling, predatory bushcrickets (katydids) that is known for its inflated tegmina and the unusually loud and low-frequency calling song of its type species. Here, we describe the songs of another two species of the genus which are much larger than the type species and have an even lower peak frequency. In addition, small and large species differ in song structure. While the type species and closely related forms have a broad banded, multi-peak song with strong components in the audio and ultrasonic range, the species treated here have an extremely narrow banded, resonant song with a carrier frequency of 2 kHz. With Q-values above 100 these sounds belong to the purest songs ever recorded in Orthoptera. Besides describing songs, stridulatory organs and a new species we discuss the possible functions of the song type. A key to the species of Aerotegmina is provided.