Diversification of the Balloon bushcrickets (Orthoptera, Hexacentrinae, Aerotegmina) in the East African mountains

Abstract

East African mountains constitute a network of isolated habitat islands among dry savannah and are thus ideal for studying species diversification processes. This study elucidated the phylogenetic and phylogeographic relationships of all bushcricket species comprising the genus Aerotegmina. Our analysis indicated that large-scale climatic and topographic processes in Africa are likely to have driven speciation in this group, and revealed the cytogenetic traits of the species. Molecular phylogeny supported the monophyly of Aerotegmina and showed that the genus probably originated in the old Eastern Arc Mountains of Tanzania and Kenya. Two lineages were distinguished: small- and large-sized species with geographically distinct habitats. The underlying processes are thought to be eight dispersals, ten vicariance events, and one extinction event linked to repeated fragmentation of the African rainforest. Those processes, in conjunction with habitat change, probably also led to the spatial separation of the species into a northern clade with a diploid number of chromosomes 2n = 32 + X0 or 2n = 30 + neo-XY and a southern clade with a reduced number of chromosomes (2n = 28 + X0 or 24 + neo-X1X2Y). Karyotype analysis suggests that Aerotegmina is currently in the process of speciation.

A new species of Burttia Dirsh (Caelifera, Acridoidea, Acrididae, Catantopinae) from the Eastern Arc Mountains of Tanzania

“…Even fully alate and thus more mobile Orthoptera speciated in the Eastern Arc Mountains and in coastal forests such as the Phaneropterinae Lunidia Hemp, 2010 (Hemp et al 2010;Hemp 2017), showing on the one hand that the Eastern Arc Mountains harbor many old taxa on a generic level, isolated many million years ago during the fragmentation of the once continuous forest belt connecting west, central, and east Africa. On the other hand, climatic fluctuations over the past few million years were probably the motor for young radiations in the above-mentioned genera, as shown for the Hexacentrinae genus Aerotegmina Hemp, 2001(Grzywacz et al 2021 or suggested for the Pseudophyllinae Pseudotomias Hemp, 2016(Hemp 2016. Pseudotomias, or Stenampyx Hemp, 2020 (Hemp 2020) probably have close relatives in central and west Africa.…”

Description of three new species of predatory GenusHexacentrus(Orthoptera: Tettigoniidae) from India, with bioacoustic and morphological characterization

“…Hexacentrus species (Hexacentrinae, Tettigoniidae, Orthoptera) are small to moderate-sized predatory katydids (Heller 1986), found largely in Africa, Asia, Australia, and the Pacific (Farooqi & Usmani 2018;Grzywacz et al 2021). Hexacentrus species are largely green with brown segments and are well camouflaged in bushes.…”

Highly divergent karyotypes and barcoding of the East African genus Gonatoxia Karsch (Orthoptera: Phaneropterinae)

“…Mountainous East Africa is known for its high degree of biodiversity and endemism, especially along the so-called Eastern Arc Mountains, stretching through Tanzania and southern Kenya. East Africa is a hotspot of biodiversity of many orthopteran taxa, including bushcrickets 37 – 39 . In the last few years, numerous papers have been published on East African Phaneropterinae taxa, including descriptions of several new genera and many species combined with genetic studies, mostly at the chromosome level e.g.…”

“…Rapid speciation was not only observed in flightless species with low mobility (e.g. in Lentulidae 55 , and Karniellina 51 – 53 , 57 , 59 – 61 or Hexacentrinae 39 ), but also in fully alate and thus mobile taxa (e.g. in Eurycorypha 37 or Amytta 62 ).…”