Review of the Plangia graminea (Serville) complex and the description of new Plangia species from East Africa (Orthoptera: Phaneropteridae, Phaneropterinae) with data on habitat, bioacoustics, and chromosomes

The Plangia graminea complex is partly reviewed and two new species of Plangia are described, Plangia multimaculata n. sp. from savanna habitats and Plangia satiscaerulea n. sp. from the submontane zones in northern Tanzania. Plangia compressa (Walker 1869) is synonymized with P. graminea (Serville, 1838). Data on habitat, bioacoustics, and chromosomes are provided. Both analyzed Plangia species showed the same chromosomal number. Compared to other investigated African Phaneropterinae, Plangia had a reduced chromosome number and thus shows a derived condition in its genome. The sex chromosomes differed morphologically in both investigated species of Plangia suggesting different mechanisms leading to these differences. Niche specialization and the male calling song are discussed as drivers for speciation in fully alate and thus mobile taxa.