Predicting where a radiation will occur: Acoustic and molecular surveys reveal overlooked diversity in Indian Ocean Island crickets (Mogoplistinae: Ornebius)

Recent theory suggests that the geographic location of island radiations (local accumulation of species diversity due to cladogenesis) can be predicted based on island area and isolation. Crickets are a suitable group for testing these predictions, as they show both the ability to reach some of the most isolated islands in the world, and to speciate at small spatial scales. Despite substantial song variation between closely related species in many island cricket lineages worldwide, to date this characteristic has not received attention in the western Indian Ocean islands; existing species descriptions are based on morphology alone. Here we use a combination of acoustics and DNA sequencing to survey these islands for Ornebius crickets. We uncover a small but previously unknown radiation in the Mascarenes, constituting a three-fold increase in the Ornebius species diversity of this archipelago (from two to six species). A further new species is detected in the Comoros. Although double archipelago colonisation is the best explanation for species diversity in the Seychelles, in situ cladogenesis is the best explanation for the six species in the Mascarenes and two species of the Comoros. Whether the radiation of Mascarene Ornebius results from intra- or purely inter- island speciation cannot be determined on the basis of the phylogenetic data alone. However, the existence of genetic, song and ecological divergence at the intra-island scale is suggestive of an intra-island speciation scenario in which ecological and mating traits diverge hand-in-hand. Our results suggest that the geographic location of Ornebius radiations is partially but not fully explained by island area and isolation. A notable anomaly is Madagascar, where our surveys are consistent with existing accounts in finding no Ornebius species present. Possible explanations are discussed, invoking ecological differences between species and differences in environmental history between islands. (Résumé d'auteur

Old lineage on an old island : Pixibinthus, a new cricket genus endemic to New Caledonia shed light on gryllid diversification in a hotspot of biodiversity

Few studies have focused on the early colonization of New Caledonia by insects, after the re-emergence of the main island, 37 Myr ago. Here we investigate the mode and tempo of evolution of a new endemic cricket genus, Pixibinthus, recently discovered in southern New Caledonia. First we formally describe this new monotypic genus found exclusively in the open shrubby vegetation on metalliferous soils, named 'maquis minier', unique to New Caledonia. We then reconstruct a dated molecular phylogeny based on five mitochondrial and four nuclear loci in order to establish relationships of Pixibinthus within Eneopterinae crickets. Pixibinthus is recovered as thesister clade of the endemic genus Agnotecous, mostly rainforest-dwellers. Dating results show that the island colonization by their common ancestor occurred around 34.7 Myr, shortly after New Caledonia re-emergence. Pixibinthus and Agnotecous are then one of the oldest insect lineages documented so far for New Caledonia. This discovery highlights for the first time two clear-cut ecological specializations between sister clades, as Agnotecous is mainly found in rainforests with 19 species, whereas Pixibinthus is found in open habitats with a single documented species. The preference of Pixibinthus for open habitats and of Agnotecous for forest habitats nicely fits an acoustic specialization, either explained by differences in body size or in acoustic properties of their respective habitats. We hypothesize that landscape dynamics, linked to major past climatic events and recent change in fire regimes are possible causes for both present-day low diversity and rarity in genus Pixibinthus. The unique evolutionary history of this old New Caledonian lineage stresses the importance to increase our knowledge on the faunal biodiversity of 'maquis minier', in order to better understand the origin and past dynamics of New Caledonian biota

A new species of the genus Platycleis Fieber, 1853 (Orthoptera: Tettigoniidae) from the Western and Trans Himalayas, India

In India, the genus Platycleis was known only from P. kashmira (Uvarov, 1930). A new species, P. rahmoiensis sp. nov., with its type locality in Pulwama, Jammu &amp; Kashmir, Western Himalayas is described in this study. Additional specimens collected from the Ladakh region of the Trans Himalayas, India, indicate its broader distribution. The new species is described with detailed external and internal characters together with a dichotomous key for its distinction from P. kashmira. Based on the new species, we also report data on the acoustic signal from the genus for the first time from India.&#x0D;  </jats:p

Revision of the high-altitude genus Hyphinomos Uvarov, 1921 (Orthoptera: Tettigoniidae) with a redescription and new data on mating behavior and acoustic signals of H. svenhedini Ramme, 1950

High mountains are known for their unique habitats and extreme climatic conditions. Many inhabitants of this area are specialists and are known as hypsobionts. Among Ensifera, only selected species from different genera are true hypsobionts. Species in the genus Hyphinomos are one of them. Hyphinomos occurs only between 3800 and 5500 m a.s.l., and is known from two species,  fasciata Uvarov, 1921 and svenhedini Ramme, 1950. Until recently they were both known only from their type localities situated in mountain ranges of the Himalayas. In this paper, we amend the description of H. svenhedini by adding new data on its distribution, habitat, structure of the male genitalia, stridulatory structures, acoustic signals (long-distance and courtship), and mating behavior. In addition, we have revised the description of Hyphinomos.&#x0D;  </jats:p

Titanogryllus n. gen., the largest Gryllinae cricket from the Neotropical Region with three new species from the Brazilian Atlantic Forest (Orthoptera, Grylloidea, Gryllidae)

Jaiswara, Ranjana, Souza-Dias, Pedro G. B., Campos, Lucas Denadai De, Redü, Darlan R., De Mello, Francisco De A. G., Desutter-Grandcolas, Laure (2018): Titanogryllus n. gen., the largest Gryllinae cricket from the Neotropical Region with three new species from the Brazilian Atlantic Forest (Orthoptera, Grylloidea, Gryllidae). Zootaxa 4402 (3): 487-507, DOI: https://doi.org/10.11646/zootaxa.4402.3.