An article published by IRD researchers and their partners at the national history museum describes Pixibinthus, a new tiny but exceptional kind of relict cricket genus endemic to southern New Caledonia.
Since the re-emergence of the main island of New Caledonia 37 million years ago, very few studies have looked at the evolutionary history of insects. Researchers have now studied the evolution of the cricket that is endemic to New Caledonia. On the basis of a phylogenetic study, they traced its evolutionary history and highlighted the insect’s ecological specialisation. The new monotypic cricket genus Pixibinthus was formally described based on morphological, anatomical, acoustic and molecular information.
This cricket is found exclusively in the open shrubby vegetation on metalliferous soils, named ‘maquis minier’, unique to New Caledonia. Based on a molecular phylogenetic reconstruction, Pixibinthus is recovered as the sister clade of the endemic genus Agnotecous, mostly rainforest-dwellers.
Molecular dating results show that the island colonisation by their common ancestor occurred shortly after New Caledonia re-emergence. Pixibinthus and Agnotecous are therefore one of the oldest insect lineages documented so far for New Caledonia.
Pixibinthus sonicus exhibits an entirely ultrasonic call corresponding to the highest frequency ever recorded in crickets, with a dominant frequency of 27.9 ± 2.8 kHz.