Biogeographical and evolutionary aspects of a Guineo-Congolian bushcricket tribe: Revision of the genera Cestromoecha Karsch, 1893 and Poreuomena Brunner von Wattenwyl, 1878, with the description of new species (Orthoptera, Tettigoniidae, Phaneropterinae)

Abstract

The genera Cestromoecha and Poreuomena of the tribe Poreuomenini in Phaneropterinae are revised and new generic characters are given for both genera, and six new species are described in Poreuomena. The newly described species are P. biaculeata sp. nov., P. eala sp. nov., P. gracilicercata sp. nov., P. ivoriana sp. nov., P. matthaei sp. nov., and P. tshuapa sp. nov. Based on characters defining the two genera, three species so far listed under Cestromoecha are transferred to Poreuomena: P. crassipes Karsch, 1890, P. laeglae (Massa, 2015), and P. magnicerca (Massa, 2013). One species of Cestromoecha, C. mundamensis Karsch, 1896, is synonymised with C. tenuipes (Karsch, 1890) since no morphological differences were detected between the type specimens. Thus, two species remain with Cestromoecha, and Poreuomena now contains 16 species. Morphological closely-related species of Poreuomena suggest rapid speciation in the Congo Basin due to several expansions and shrinkages of the Guineo-Congolian forest belt since the Oligocene. At least two different morphological lineages are discernible. On the other hand the genus Cestromoecha Karsch, 1893 is a species-poor taxon.