02624nas a2200181   4500008004100000245015900041210006900200520194700269100001902216700002002235700003102255700002002286700002502306700001702331700002002348700002102368856005302389       2016                        eng d00aOld Lineage on an Old Island: Pixibinthus, a New Cricket Genus Endemic to New Caledonia Shed Light on Gryllid Diversification in a Hotspot of Biodiversity0 aOld Lineage on an Old Island Pixibinthus a New Cricket Genus End3 a<p>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 &lsquo;maquis minier&rsquo;, 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 &lsquo;maquis minier&rsquo;, in order to better understand the origin and past dynamics of New Caledonian biota.</p>
1 aAnso, Jérémy1 aBarrabé, Laure1 aDesutter-Grandcolas, Laure1 aJourdan, Hervé1 aGrandcolas, Philippe1 aDong, Jiajia1 aROBILLARD, TONY1 aFontaneto, Diego  uhttps://dx.plos.org/10.1371/journal.pone.0150920