Hidden island endemic species and their implications for cryptic speciation within soil arthropods

Specialisation to the soil environment is expected to constrain the spatial scale of diversification within animal lineages. In this context, flightless arthropod lineages, adapted to soil environments, but with broad geographical ranges, rep-resent something of an anomaly. Here we investigate the diversification process within one such ‘anomalous’ soil specialist, an eyeless and flightless beetle species strongly adapted to the endogean environment but distributed across several oce-anic islands.