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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.

Anso J, Barrabé L, Desutter-Grandcolas L, Jourdan H, Grandcolas P, Dong J, Robillard T - PLoS ONE (2016)

Bottom Line: Dating results show that the island colonization by their common ancestor occurred around 34.7 Myr, shortly after New Caledonia re-emergence.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 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.

View Article: PubMed Central - PubMed

Affiliation: Muséum national d'Histoire naturelle, Institut de Systématique, Évolution, Biodiversité, ISYEB - UMR 7205 - CNRS, MNHN, UPMC, EPHE, Sorbonne Universités, Paris, France.

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.

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Detailed morphology of Pixibinthus sonicus.(A)Dorsal view of the female face. (B) Facial of the female face. (C) Lateral view of the anterior body part of female. (D) Dorsal view of detailed FWs for female. (E) Dorsal view of detailed FWs for male (E). (F) Stridulatory file with SEM. Scale bars = 1 mm for (A), (B), (C), (D), (E); 50 μm for (F).
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pone.0150920.g002: Detailed morphology of Pixibinthus sonicus.(A)Dorsal view of the female face. (B) Facial of the female face. (C) Lateral view of the anterior body part of female. (D) Dorsal view of detailed FWs for female. (E) Dorsal view of detailed FWs for male (E). (F) Stridulatory file with SEM. Scale bars = 1 mm for (A), (B), (C), (D), (E); 50 μm for (F).

Mentions: Male: Metanotal glands absent. Lateral and dorsal fields of FWs of similar lengths (Figs 2 and 3). 1A vein (file) with a marked angle (only curved in Lebinthus). Harp with one bisinuated oblique vein. Mirror and d2 cell not differentiated from other cells of D alignment. Stridulatory file with teeth both on transverse and longitudinal parts of 1A. Diagonal vein well visible. CuP absent but claval fold visible. CuA faint, slightly curved inward. Median fold small, located on dorsum as in Lebinthus and Agnotecous. Chord cells differentiated. Apical field including only few cells posterior to mirror (alignment E). Subgenital plate clog-shaped, twice as long as sternites; inner side of subgenital plate with lateral swellings.


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.

Anso J, Barrabé L, Desutter-Grandcolas L, Jourdan H, Grandcolas P, Dong J, Robillard T - PLoS ONE (2016)

Detailed morphology of Pixibinthus sonicus.(A)Dorsal view of the female face. (B) Facial of the female face. (C) Lateral view of the anterior body part of female. (D) Dorsal view of detailed FWs for female. (E) Dorsal view of detailed FWs for male (E). (F) Stridulatory file with SEM. Scale bars = 1 mm for (A), (B), (C), (D), (E); 50 μm for (F).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4814057&req=5

pone.0150920.g002: Detailed morphology of Pixibinthus sonicus.(A)Dorsal view of the female face. (B) Facial of the female face. (C) Lateral view of the anterior body part of female. (D) Dorsal view of detailed FWs for female. (E) Dorsal view of detailed FWs for male (E). (F) Stridulatory file with SEM. Scale bars = 1 mm for (A), (B), (C), (D), (E); 50 μm for (F).
Mentions: Male: Metanotal glands absent. Lateral and dorsal fields of FWs of similar lengths (Figs 2 and 3). 1A vein (file) with a marked angle (only curved in Lebinthus). Harp with one bisinuated oblique vein. Mirror and d2 cell not differentiated from other cells of D alignment. Stridulatory file with teeth both on transverse and longitudinal parts of 1A. Diagonal vein well visible. CuP absent but claval fold visible. CuA faint, slightly curved inward. Median fold small, located on dorsum as in Lebinthus and Agnotecous. Chord cells differentiated. Apical field including only few cells posterior to mirror (alignment E). Subgenital plate clog-shaped, twice as long as sternites; inner side of subgenital plate with lateral swellings.

Bottom Line: Dating results show that the island colonization by their common ancestor occurred around 34.7 Myr, shortly after New Caledonia re-emergence.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 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.

View Article: PubMed Central - PubMed

Affiliation: Muséum national d'Histoire naturelle, Institut de Systématique, Évolution, Biodiversité, ISYEB - UMR 7205 - CNRS, MNHN, UPMC, EPHE, Sorbonne Universités, Paris, France.

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.

Show MeSH
Related in: MedlinePlus