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

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Cardiodactylus Saussure 1878

Genus <i>Cardiodactylus</i> Saussure, 1878 <p> <i>Cardiodactylus</i> Saussure, 1878: 657.</p> <p> TYPE SPECIES. — <i>Platydactylus novaeguineae</i> de Haan, 1844 by subsequent designation (Kirby 1906).</p> <p>ILLUSTRATIONS. — Habitus: Fig. 15C. Male genitalia: Robillard & Ichikawa 2009: fig.4. Calling song: Robillard & Ichikawa 2009: fig. 7.</p> <p>DIAGNOSIS. — After Robillard & Ichikawa (2009). Large, fusiform species, with long FWs, HWs and cerci in both sexes. Coloration variegated, with yellow, whitish, brown and black; palpi yellow to white, with or without a brown apical ring on joint 5. Eyes slightly protruding. Fastigium as wide as scape, thus relatively narrow compared to other eneopterine genera. Pronotum transverse. TI with an inner and an outer tympana.</p> <p> <b>Male.</b> Stridulum complete; harp longer than wide, with two strongly bisinuated, oblique veins; mirror well delimited, more or less clearly separated from apical field; apical field elongate with several cell alignments. Male genitalia: pseudepiphallic sclerite very long, greatly narrowed at mid length, setose laterally and ventrally, with two high dorsal crests partly fused dorsally; rami short and wide.</p> <p> <b>Female.</b> Ovipositor long, apex lanceolate and flattened laterally. Female genitalia: copulatory papilla with rounded sclerotized base and apex.</p> <p> CALLING SONG. — The call of <i>C. novaeguineae</i> (de Haan, 1844) is complex, with two different types of echemes. The dominant frequency is carried on the third harmonic (Robillard & Ichikawa 2009).</p> <p> DISTRIBUTION. — <i>Cardiodactylus</i> is highly diversified in the western Pacific; it is known in New Caledonia by only <i>C. novaeguineae</i>, a widely distributed species in Oceania (Robillard & Ichikawa 2009).</p> <p> HABITAT. — <i>Cardiodactylus novaeguineae</i> is restricted to opened forest in coastal areas, where it forages from afternoon to night on vegetation (Robillard & Ichikawa 2009).</p>Published as part of <i>Desutter-Grandcolas, Laure, Anso, Jérémy & Jourdan, Hervé, 2016, Crickets of New Caledonia (Insecta, Orthoptera, Grylloidea): a key to genera, with diagnoses of extant genera and descriptions of new taxa, pp. 405-452 in Zoosystema 38 (4)</i> on page 446, DOI: 10.5252/z2016n4a1, <a href="http://zenodo.org/record/4578278">http://zenodo.org/record/4578278</a&gt

Pseudotrigonidium Chopard 1915

Genus <i>Pseudotrigonidium</i> Chopard, 1915 <p> <i>Pseudotrigonidium</i> Chopard, 1915: 152.</p> <p> TYPE SPECIES. — <i>Pseudotrigonidium sarasini</i> Chopard, 1915 by original designation.</p> <p> ILLUSTRATIONS. — Habitus: Fig. 2D; Otte <i>et al.</i> 1987: fig. 21 (under <i>Tremellia</i>); Anso <i>et al.</i> 2016a: fig. 5. Male genitalia: Otte <i>et al.</i> 1987: fig. 24 (under <i>Tremellia</i>); Desutter-Grandcolas 1997a: figs 18-19 (under <i>Tremellia</i>). Calling song: Anso <i>et al.</i> 2016a: fig. 4.</p> <p> <b>Male.</b> Two stridulum conditions: 1) Stridulum complete and functional; harp with four or five oblique, parallel veins, the most distal one concave; mirror crossed by two parallel veins. CuP present and short; and 2) Stridulum lacking, in micropterous (a file sometimes present) and apterous species. Subgenital plate long, narrow and high. Male genitalia: pseudepiphallic sclerite very elongate (except in <i>P. aptera</i> Desutter-Grandcolas, 1997 and <i>P. ana</i> Anso & Desutter-Grandcolas, 2016); pseudepiphallic parameres well-developed, lateral, making wide, often indented plates; arc complete and wide; ectophallic apodemes short; ectophallic fold often hyperthelic, extending dorsally between pseudepiphallic lateral parts; endophallic sclerite U-shaped, most often elongate; endophallic apodeme crestlike; no dorsal cavity.</p> <p> <b>Female.</b> FWs rounded, with thick longitudinal and transversal veins. Ovipositor short to very short; valve apex thick and rounded, with teeth. Female genitalia: copulatory papilla very small, annular with thicker anterior part.</p> <p> DISTRIBUTION. — Diversified in Oceania and Indomalaysia. In New Caledonia, <i>Pseudotrigonidium</i> is known throughout the whole Grande Terre; it is not yet reported from the Loyalty Islands.</p> <p> HABITAT. — <i>Pseudotrigonidium</i> inhabits the understorey of forest vegetation, where its is active at night. Winged males are often found singing under the leaves of <i>Pandanus</i> or treeferns. <i>Pseudotrigonidium</i> hides during the day either in plant structures, such as inside the stems of dead fern leaves, or in the leaf litter and dead plant material accumulated at the base of tree trunks.</p>Published as part of <i>Desutter-Grandcolas, Laure, Anso, Jérémy & Jourdan, Hervé, 2016, Crickets of New Caledonia (Insecta, Orthoptera, Grylloidea): a key to genera, with diagnoses of extant genera and descriptions of new taxa, pp. 405-452 in Zoosystema 38 (4)</i> on page 415, DOI: 10.5252/z2016n4a1, <a href="http://zenodo.org/record/4578278">http://zenodo.org/record/4578278</a&gt

Amonemobius Otte, Alexander & Cade 1987

Genus <i>Amonemobius</i> Otte, Alexander & Cade, 1987 <p> <i>Amonemobius</i> Otte, Alexander & Cade, 1987: 410.</p> <p> <i>Amonomobius</i> – Otte, Alexander & Cade 1987: 399 (typ. err.).</p> <p> TYPE SPECIES. — <i>Amonemobius vexans</i> Otte, 1987 by original designation.</p> <p> ILLUSTRATIONS. — Habitus pp: Otte <i>et al.</i> 1987: fig. 14G. Male genitalia: Otte <i>et al.</i> 1987: fig. 17B.</p> <p> DIAGNOSIS. — After Otte <i>et al.</i> (1987). Very similar to <i>Koghiella</i>. TI with a large outer tympanum. Head dorsum mostly pale but occiput with four small black stripes; region posterior to eyes black; dorsum of pronotum largely pale with a dark patch in each corner. Male genitalia: pseudepiphallus with a deep median cleft; pseudepiphallic parameres longer than pseudepiphallic sclerite (Otte <i>et al.</i> 1987: fig. 17B).</p> <p>DISTRIBUTION. — Endemic to New Caledonia. Known from the type locality of the type species only (Amoa river near Poindimié).</p> <p> HABITAT. — Otte <i>et al.</i> (1987: 411) mention that <i>A. vexans</i> has been “found on banks along a road through the forest in the Amoa valley”.</p>Published as part of <i>Desutter-Grandcolas, Laure, Anso, Jérémy & Jourdan, Hervé, 2016, Crickets of New Caledonia (Insecta, Orthoptera, Grylloidea): a key to genera, with diagnoses of extant genera and descriptions of new taxa, pp. 405-452 in Zoosystema 38 (4)</i> on page 422, DOI: 10.5252/z2016n4a1, <a href="http://zenodo.org/record/4578278">http://zenodo.org/record/4578278</a&gt

Phaloriinae Gorochov 1985

Subfamily PHALORIINAE Gorochov, 1985 <p>DIAGNOSIS. — See Desutter-Grandcolas (2015).</p>Published as part of <i>Desutter-Grandcolas, Laure, Anso, Jérémy & Jourdan, Hervé, 2016, Crickets of New Caledonia (Insecta, Orthoptera, Grylloidea): a key to genera, with diagnoses of extant genera and descriptions of new taxa, pp. 405-452 in Zoosystema 38 (4)</i> on page 415, DOI: 10.5252/z2016n4a1, <a href="http://zenodo.org/record/4578278">http://zenodo.org/record/4578278</a&gt

Anaxipha Saussure 1874

Genus <i>Anaxipha</i> Saussure, 1874 <p> <i>Anaxipha</i> Saussure, 1874: 370.</p> <p> TYPE SPECIES. — <i>Gryllus pulicarius</i> Burmeister, 1838 by subsequent designation (Rehn, 1905).</p> <p> ILLUSTRATIONS. — Habitus: Fig. 3A; Otte & Alexander 1983: fig. 161. Male genitalia: Otte <i>et al.</i> 1987: fig. 19. Calling songs: Otte & Alexander 1983: fig. 163.</p> <p>EMENDED DIAGNOSIS FOR NEW CALEDONIAN SPECIES. — After Otte & Alexander (1983) and material preserved in MNHN. Head dorsum not fully flat between eyes. TI with an outer tympanum; inner tympanum lacking. FWs not hairy. HWs not developed. TIII with three pairs of long and thin alternate subapical spurs; only five relatively short apical spurs, ventral inner spur lacking.</p> <p> <b>Male.</b> No dorsal gland on abdomen. FWs flat in lateral view. Stridulatory apparatus complete; mirror well-developed, most often diamond shaped. Apical field reduced. Metanotal glands present or lacking. Male genitalia: pseudepiphallus well-developed, symmetrical or almost so, and not hyperthelic; distal pseudepiphallus with two lateral long and thin lobes, and two shorter median ones; on each side, median and lateral lobes separated (<i>Anaxipha</i> undescribed species) or not (<i>Anaxipha caledonica</i> Otte, 1987) by an additional thin process; distal margins of lobes plain (<i>Anaxipha caledonica</i>, Otte <i>et al.</i> 1987: fig. 19B) or serrated (<i>Anaxipha</i> undescribed species), resembling some species of <i>Vanuaxipha</i> Otte & Cooper, 2007; pseudepiphallic parameres symmetrical, flat.</p> <p> <b>Female.</b> FW length and colour as in males. Ovipositor: distal margins of dorsal and ventral valves highly crenulated (see Otte <i>et al.</i> 1987: fig. 19C).</p> <p> DISTRIBUTION. — World-wide. Known in New Caledonia by only one species from Grande Terre, on the western coast near Koumac (<i>A. caledonica</i>). Additional material attests the presence of <i>Anaxipha</i> at Parc provincial de la Rivière Bleue in the South of Grande Terre and at the base of Mont Mou (MNHN).</p>Published as part of <i>Desutter-Grandcolas, Laure, Anso, Jérémy & Jourdan, Hervé, 2016, Crickets of New Caledonia (Insecta, Orthoptera, Grylloidea): a key to genera, with diagnoses of extant genera and descriptions of new taxa, pp. 405-452 in Zoosystema 38 (4)</i> on pages 415-416, DOI: 10.5252/z2016n4a1, <a href="http://zenodo.org/record/4578278">http://zenodo.org/record/4578278</a&gt

Gryllidae Laicharting 1781

Family GRYLLIDAE Laicharting, 1781 <p>REMARK</p> <p>Gryllidae are represented in New Caledonia by Eneopterinae Saussure, 1893, Euscyrtinae Gorochov, 1985, Gryllinae Laicharting, 1781, Podoscirtinae Saussure, 1878 and Oecanthinae Blanchard, 1845.</p>Published as part of <i>Desutter-Grandcolas, Laure, Anso, Jérémy & Jourdan, Hervé, 2016, Crickets of New Caledonia (Insecta, Orthoptera, Grylloidea): a key to genera, with diagnoses of extant genera and descriptions of new taxa, pp. 405-452 in Zoosystema 38 (4)</i> on page 430, DOI: 10.5252/z2016n4a1, <a href="http://zenodo.org/record/4578278">http://zenodo.org/record/4578278</a&gt

Oecanthus Serville 1831

Genus <i>Oecanthus</i> Serville, 1831 <p> <i>Oecanthus</i> Serville, 1831: 38.</p> <p> TYPE SPECIES. — <i>Gryllus pellucens</i> Scopoli, 1763 by subsequent designation (Kirby 1906).</p> <p>ILLUSTRATIONS. — Habitus: Fig. 15B; Otte & Alexander 1983: fig. 298. Male genitalia: Otte & Alexander 1983: fig. 301D. Calling song: fig. 16.</p> <p>DIAGNOSIS. — Medium sized species, with narrow body and very thin FIII. Lightly coloured, most often green or very light brown. FWs translucent. Head prognathous, elongate. Eyes very little prominent; only two ocelli present, often not clear.Fastigium narrower than scapes; scapes longer than wide. Maxillary palpi moderately elongate, all joints tubular and very thin; joint 5 the longest, apex obliquely truncate. Pronotum longer than wide, distinctly narrowed anteriorly; lower margin of lateral lobes somewhat raised dorsally. Legs all very thin. TI inflated at level of well-developed inner and outer tympana. TIII furrowed dorsally; with three inner and three outer apical spurs, dorsal spur the longest on each side; with six or seven inner and five outer small subapical spurs; serrulation present both above and between subapical spurs. Basitarsomeres III very long, without dorsal spine. Second tarsomeres not flattened. Claws bifidous at base. Cerci short. FWs always present. HWs most often longer than FWS.</p> <p> <b>Male.</b> Metanotum gland very developed (Hancock’s gland). FWs translucent, covering abdomen and very wide; stridulum well-developed, FW wider at mirror level. Stridulum complete; file straight; harp with few transverse veins; mirror divided into two very wide cells. Apical field reduced; chords all parallel and closely set; chords 1 and 2 fused basally. Lateral field specialized. Male genitalia little sclerotized; pseudepiphallus short, anterior margin concave, distal apex shortly bifidous; pseudepiphallic parameres flap-like, close to pseudepiphallic apex; rami very long and thin; ectophallic fold short; ectophallic apodemes well-developed; dorsal cavity large, bordered by two longitudinal invaginations.</p> <p> <b>Female.</b> FWs and HWs as developed as in males. Ovipositor straight; dorsal valves longer than ventral valves, with thick crests.</p> <p> DISTRIBUTION. — <i>Oecanthus</i> is distributed worldwide; only one species is reported from New Caledonia, <i>Oecanthus rufescens</i> Serville, 1831, which has been described from India and recorded in Australia (Otte & Alexander 1983; Metrani & Balakrishnan 2005).</p> <p>HABITAT. — Nocturnal species singing from high herbs or schrubs in disturbed vegetation, often along road side.</p>Published as part of <i>Desutter-Grandcolas, Laure, Anso, Jérémy & Jourdan, Hervé, 2016, Crickets of New Caledonia (Insecta, Orthoptera, Grylloidea): a key to genera, with diagnoses of extant genera and descriptions of new taxa, pp. 405-452 in Zoosystema 38 (4)</i> on page 442, DOI: 10.5252/z2016n4a1, <a href="http://zenodo.org/record/4578278">http://zenodo.org/record/4578278</a&gt

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

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