title: 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.
abstract: 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 the sister 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.
authors.affiliation: Muséum national d'Histoire naturelle, Institut de Systématique, Évolution, Biodiversité, ISYEB - UMR 7205 - CNRS, MNHN, UPMC, EPHE, Sorbonne Universités, Paris, France.|Institut Méditerranéen de Biodiversité et d'Écologie marine et continentale (IMBE), Aix Marseille Université, CNRS, IRD, Avignon Université UMR IRD 237 IMBE, Centre IRD Nouméa, Nouvelle-Calédonie.
authors.forename: Jérémy
authors.initials: J
authors.lastname: Anso
authors.affiliation: Laboratoire de Botanique et d'Ecologie Végétales Appliquées, Herbarium NOU, UMR 123: botAnique et Modélisation de l'Architecture des Plantes et des vegetations (AMAP), Centre IRD Nouméa, Nouvelle-Calédonie.
authors.forename: Laure
authors.initials: L
authors.lastname: Barrabé
authors.affiliation: Muséum national d'Histoire naturelle, Institut de Systématique, Évolution, Biodiversité, ISYEB - UMR 7205 - CNRS, MNHN, UPMC, EPHE, Sorbonne Universités, Paris, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Desutter-Grandcolas
authors.affiliation: Institut Méditerranéen de Biodiversité et d'Écologie marine et continentale (IMBE), Aix Marseille Université, CNRS, IRD, Avignon Université UMR IRD 237 IMBE, Centre IRD Nouméa, Nouvelle-Calédonie.
authors.forename: Hervé
authors.initials: H
authors.lastname: Jourdan
authors.affiliation: Muséum national d'Histoire naturelle, Institut de Systématique, Évolution, Biodiversité, ISYEB - UMR 7205 - CNRS, MNHN, UPMC, EPHE, Sorbonne Universités, Paris, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Grandcolas
authors.affiliation: Muséum national d'Histoire naturelle, Institut de Systématique, Évolution, Biodiversité, ISYEB - UMR 7205 - CNRS, MNHN, UPMC, EPHE, Sorbonne Universités, Paris, France.
authors.forename: Jiajia
authors.initials: J
authors.lastname: Dong
authors.affiliation: Muséum national d'Histoire naturelle, Institut de Systématique, Évolution, Biodiversité, ISYEB - UMR 7205 - CNRS, MNHN, UPMC, EPHE, Sorbonne Universités, Paris, France.
authors.forename: Tony
authors.initials: T
authors.lastname: Robillard
mesh_terms: D000818:Animals; D044822:Biodiversity; D005260:Female; D017344:Genes, Insect; D049810:Genetic Speciation; D006135:Gryllidae / Q000033:anatomy & histology / Q000145:classification* / Q000502:physiology; D008297:Male; D058885:Multilocus Sequence Typing; D009510:New Caledonia; D010858:Pigmentation; D014828:Vocalization, Animal