Abstract
Aim
Understanding the historical biogeography of the Earth's oldest terrestrial lineages provides insights into lineage diversification in relation to plate tectonics, climate change and biome shifts at maximum timescales. We investigate the biogeography of an ancient arachnid family, dragon pseudoscorpions, which are found today in mesic (mostly temperate) forests on all continents except Antarctica and Europe, have potential origins on Pangea and comprise species with extremely limited dispersal capacities. We evaluate the respective role of continental vicariance (abiotic) and biome shifts (biotic) deep in time and unravel the evolutionary history of this ancient group.
Location
Global.
Taxon
Pseudotyrannochthoniidae (Arachnida: Pseudoscorpiones).
Methods
Five loci were sequenced for 75 Pseudotyrannochthoniidae samples collected across the globe. A matrix was compiled comprising 106 terminals and ~8800 bp, and phylogenetic analyses were performed to uncover relationships. Divergence time and ancestral range estimation analyses were used to reconstruct historical biogeography.
Results
Pseudotyrannochthoniidae was monophyletic with high support but relationships among genera did not reflect current taxonomy and instead showed geographical structuring. Pseudotyrannochthoniidae originated in East Asia during the Middle Triassic and began diversifying in the Early Cretaceous.
Main Conclusions
Diversity and distributional patterns of dragon pseudoscorpions can be explained by the interplay of continental vicariance through Pangaean breakup, and biome shifts via the spread of temperate habitats in the Cretaceous and their ongoing distributional fluctuations. Pseudotyrannochthoniidae diversification began in the Early Cretaceous as they dispersed with temperate forests across the Northern Hemisphere. Cretaceous vicariance, followed by widespread Holarctic extinction in the Late Tertiary–Quaternary, created their disjunct distribution at northern latitudes. Northern and Southern Hemisphere lineages diverged as Gondwana and Laurasia rifted, and Gondwanan breakup resulted in Afrotropical/Indomalayan and Austral clades. Austral lineages spread with temperate forests, however, cooling caused their disappearance from Antarctica and led to disjunct distributions at low latitudes.
