The tropical African genus Morgenia (Orthoptera, Tettigoniidae, Phaneropterinae) with emphasis on the spur at the mid tibia.

The authors revised the genus Morgenia Karsch, 1890 which now consists of eight species, of which three are here newly described (Morgeniaplurimaculata Massa & Moulin, sp. n., M.angustipinnata Massa, sp. n., and M.lehmannorum Heller & Massa, sp. n.). Six of the eight species occur in the Tri National Sangha (TNS) comprising Dzanga-Sangha Special Reserve and Dzanga Ndoki National Park (Central African Republic), whose high biodiversity has been recently highlighted. In particular the genus is characterised by the presence of a more or less long spur at the inner mid tibia, different in each species; in M.modulata, it moved lower down into a new position at about ¼ of tibia, which has a hollow underneath where the rest of the spur remains hidden. This is a unique known case in Phaneropterinae. Morphological characters distinguishing males of different species are presented. Bioacoustics of the new species M.lehmannorum are described. The patterns of the chromosome evolution in M.lehmannorum differ from other investigated African Phaneropterinae in terms of chromosome number and morphology, reduced ancestral chromosome number (2n = 25) implying a more derived condition.