Past climatic changes and their effects on the phylogenetic pattern of the Gondwanan relict Maindronia (Insecta: Zygentoma) in the Chilean Atacama Desert

The silverfish family Maindroniidae (Insecta: Zygentoma) consists of three described species from desert biomes in Sudan, the Arabian Peninsula and Chile. This distribution is remarkable for closely related arthropods, suggesting a Gondwanan relict group. Extensive collecting efforts in Chile show a surprisingly widespread distribution in the Atacama. These insects were even found in hyperarid areas where no other metazoans could be observed. Maindronia can thus be considered as the most adapted desert animal in the Atacama, which in turn is one of the driest deserts in the world. The common habitat preference in the Chilean Atacama, and evidently also in Sudan, suggests that hyperarid environments have always been present, at least locally, in South America over the past 120 million years. Likely, Chilean Maindronia have evolved with and within the Atacama Desert. This scenario clearly differs from that shown for other animals or plants that have more recently migrated into suitable environments in the Atacama. Phylogenetic analyses show the presence of at least five clades derived from a single ancestor and diverging in the last 15 million years. The divergence times of the clades can be attributed to palaeoclimatic changes; mostly periods of extreme hyperaridity.