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

Crickets of New Caledonia (Insecta, Orthoptera, Grylloidea): a key to genera, with diagnoses of extant genera and descriptions of new taxa

International audienc

Crickets of New Caledonia (Insecta, Orthoptera, Grylloidea): a key to genera, with diagnoses of extant genera and descriptions of new taxa

International audienc

Zoologia neocaledonica : 8. Biodiversity studies in New Caledonia

Le genre de grillons Protathra Desutter-GRandcolas, 1997a est redéfini, avec l'ajout des caractères des mâles (appareil stridulatoire, genitalia) à la diagnose originale. L'étude des spécimens nouvellement collectés permet de préciser la définition de l'espèce type Protathra gigantea Desutter-Grandcolas, 1997a, et de décrire une espèce nouvelle supplémentaire pour le genre, Protathra centralis Desutter-Grandcolas, n. sp. originaire du massif de l'Aoupinié et du Pic Amoa. Une clé d'identification des Phalangopsidae de Nouvelle-Calédonie est proposée. Le chant d'appel de Protathra gigantea est décrit, ce qui constitue la première contribution sur le comportement acoustique des Phalangopsidae néocalédoniens

Bayesian majority rule consensus tree of Eneopterinae crickets based on dataset 1, including 28 species and nine DNA markers.

<p>Bayesian posterior probability (PP) andML bootstrap (BS) support values are indicated for each node on the right. A clade with a BS < 50% or not recovered in the ML analyses is indicated with a dash. Major clades are shaded with a color scale. Horizontal bars represent the scales of substitution rates (substitution per site). Species occurring in New Caledonia are represented with the ‡ symbol.</p

Map of sampled localities in the southern part of New Caledonian Grande Terre.

<p>Blue dots indicate localities where populations of <i>Pixibinthus sonicus</i> were not found. Orange dots indicate localities where <i>P</i>. <i>sonicus</i> was found.</p

Habitat of <i>Pixibinthus sonicus</i>.

<p>(A)Low sclerophyllous ‘maquis minier’ around les Chutes de la Madeleine. (B) Detailed view of habitat in leaf litter. (C) Juvenile of <i>P</i>. <i>sonicus</i> (size: approximately 1cm).</p

Ecological, biological, morphological and dating characteristics for the three Lebinthini groups.

<p>Acoustic recording impaired by inadequate recording material are indicate with an asterisk. Body sizes of species were inferred from the FIIIL femur length measurements. Abbreviation: N/A corresponds to non-available data.</p

Predicted ecological distribution of <i>Pixibinthus sonicus</i> using ESDM.

<p>Warmer colors indicate areas with higher habitat suitability for <i>P</i>. <i>sonicus</i>. Reddots show sampling sites where <i>Pixibinthus sonicus</i> was recorded; yellowdots show sampling sites where <i>P</i>. <i>sonicus</i> was not observed.</p

Genbank accession numbers of studied taxa.

<p>Newly generated sequences are indicated with an asterisk (and would be very soon referred to a genbank accession number). The superscript numbers refer to the publication where the sequences were first published: ¹[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0150920#pone.0150920.ref027" target="_blank">27</a>], ²[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0150920#pone.0150920.ref038" target="_blank">38</a>], ³[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0150920#pone.0150920.ref039" target="_blank">39</a>], ⁴[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0150920#pone.0150920.ref040" target="_blank">40</a>], ⁵[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0150920#pone.0150920.ref041" target="_blank">41</a>], ⁶[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0150920#pone.0150920.ref042" target="_blank">42</a>], ⁷[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0150920#pone.0150920.ref043" target="_blank">43</a>], ⁸[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0150920#pone.0150920.ref037" target="_blank">37</a>], ⁹[<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0150920#pone.0150920.ref044" target="_blank">44</a>].</p