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

Data for: Relicts and radiations: Phylogenomics of an Australasian lizard clade with east Gondwanan origins (Gekkota: Diplodactyloidea)

This repository stores data associated with the published article 'Relicts and radiations: Phylogenomics of an Australasian lizard clade with east Gondwanan origins (Gekkota: Diplodactyloidea)', available at https://www.sciencedirect.com/science/article/pii/S1055790319302027?via%3Dihub#!. Included here are the cleaned in-target UCE fasta assemblies for the 290 gecko samples used in this study. For BAM files of cleaned assemblies and the raw reads, please contact the corresponding author. For phylogenies, specimen lists, and other data, please see original article

Data for: Relicts and radiations: Phylogenomics of an Australasian lizard clade with east Gondwanan origins (Gekkota: Diplodactyloidea)

This repository stores data associated with the published article 'Relicts and radiations: Phylogenomics of an Australasian lizard clade with east Gondwanan origins (Gekkota: Diplodactyloidea)', available at https://www.sciencedirect.com/science/article/pii/S1055790319302027?via%3Dihub#!. Included here are the cleaned in-target UCE fasta assemblies for the 290 gecko samples used in this study. For BAM files of cleaned assemblies and the raw reads, please contact the corresponding author. For phylogenies, specimen lists, and other data, please see original article

Crossing the line: increasing body size in a trans-Wallacean lizard radiation (Cyrtodactylus, Gekkota)

The region between the Asian and Australian continental plates (Wallacea) demarcates the transition between two differentiated regional biotas. Despite this striking pattern, some terrestrial lineages have successfully traversed the marine barriers of Wallacea and subsequently diversified in newly colonized regions. The hypothesis that these dispersals between biogeographic realms are correlated with detectable shifts in evolutionary trajectory has however rarely been tested. Here, we analyse the evolution of body size in a widespread and exceptionally diverse group of gekkotan lizards (Cyrtodactylus), and show that a clade that has dispersed eastwards and radiated in the Australopapuan region appears to have significantly expanded its body size 'envelope' and repeatedly evolved gigantism. This pattern suggests that the biotic composition of the proto-Papuan Archipelago provided a permissive environment in which new colonists were released from evolutionary constraints operating to the west of Wallacea.Paul M. Oliver, Phillip Skipwith and Michael S.Y. Le

The Jacobina Paleoproterozoic gold-bearing conglomerates, Bahia, Brazil: a "hydrothermal shear-reservoir" model.

The N–S Jacobina foreland basin is a Paleoproterozoic basin (2080 to 1900 Ma) of stacked detrital and schist formations developed along a sinistral wrench–overthrust fault of the Transamazonian orogeny. At least five successive stages are identified in the westward progradation of the basin, wherein bedding-parallel strike–slip thrusts and prograde metamorphism indicate progressive involvement in the Transamazonian collision. Shearing and associated metamorphic recrystallization indicate a high geothermal gradient and a gradual loading of the underthrust units, with those to the east being deeper seated than those to the west. Basic–ultrabasic dykes and granite stocks cross-cut the lithologies and contributed to the thermal evolution. Conglomerates and chaotic breccia layers found in several formations mark periods of tectonic instability accompanied by erosion of the earlier stages of basin development. Multistage hydrothermal activity is indicated by a widespread alteration with gold-bearing quartz lodes, conglomerates showing a sulphide–gold–Cr–mineral association, leaching of ultrabasic rocks, and emerald mineralization related to late-tectonic granite emplacement. The economic gold-bearing clastic sediments (conglomerates and minor quartzites deposited during the fourth unit/stage of basin development) have generally been interpreted according to the "modified paleoplacer" model. Such a model, which implies the existence of a gold preconcentration within the quartz–pebble conglomerates, is supported by the lithological controls, reworked pebbles (e.g. cataclastic quartz, quartz–pyrite mylonite and rare fuchsite-bearing rocks) that had been hydrothermally altered during an earlier hydrothermal stage, and lead isotopic compositions revealing an Archean inheritance that is partly preserved in galena inclusions. New basin-scale structural and metallogenic data obtained by the authors, suggest a basin model characterized by successive cycles of sedimentation–faulting/thrusting–erosion ("cannibalism" model) that favours both a "paleoplacer" model and a "mesothermal shear-zone-related epigenetic" model. Heterochronous shear zones, formed between 1988 and 1912 Ma during the development of the basin, acted as feeder zones for postsedimentary mesothermal quartz–tourmaline–muscovite/fuchsite lodes, which constitute a possible source of the reworked hydrothermally altered pebbles. These shear zones controlled (a) an acid leaching of the sediments and the subsequent development of Al-rich assemblages interpreted as advanced argillic alteration zones, and (b) a sulphidation process affecting detrital ilmenite and magnetite and responsible for the high concentration of gold within shear veins containing assemblages of Cr–Ni-bearing minerals (euhedral chromite, Cr–rutile, linnaeite, Cr–tourmaline and fuchsite) and euhedral pyrite that crystallized over andalusite. The conglomerates, with their pore and fissure permeability, acted as a "reservoir and trap" for the mineralizing fluids to give a "hydrothermal shear-reservoir" model

Phylogeography, hotspots and conservation priorities: an example from the Top End of Australia

Abstract not availableD.F. Rosauer, M.P.K. Blom, G. Bourke, S. Catalano, S. Donnellan, G. Gillespie, E. Mulder, P.M. Oliver, S. Potter, R.C. Pratt, D.L. Rabosky, P.L. Skipwith, C. Morit