Few studies have focused on the early colonization of New Caledonia by insects, after the reemergence of the main island, 37 Myr ago. The new monotypic cricket genus Pixibinthus was formally described based on morphological, anatomical, acoustic and molecular information. It is found exclusively in the open shrubby vegetation on metalliferous soils, named ‘maquis minier’, unique to New Caledonia. Based on a molecular phylogenetic reconstruction (five mitochondrial and four nuclear loci), Pixibinthus is recovered as the sister clade of the endemic genus Agnotecous, mostly rainforest-dwellers. Molecular 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.
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. In terms of temporal pattern, the call of Pixibinthus sonicus is a rather long trill lasting 38.2 ± 7.4 s and made of 918 ± 130 syllables, with a period of 152.8 ± 72.2 s (at 25°C). Syllables last 18.4 ± 2.5 ms, with a period of 41.7 ± 16 ms. The sound amplitude gradually increases during the 300 to 400 first syllables, and remains high and constant until the end of the trill.