Fragments of time: Divergence dating and biogeographic history of Malagasy millipede assassin bugs (Heteroptera: Reduviidae: Ectrichodiinae)

Millipede assassin bugs (Hemiptera: Reduviidae: Ectrichodiinae) are a diverse group (>600 species, 119 genera) of specialized millipede predators. Only 10 species are documented from Madagascar, which is a biodiversity hotspot and of critical conservation priority. The California Academy of Sciences’ (CAS) Terrestrial Arthropod Inventory of Madagascar survey addresses the need for taxonomic exploration of Malagasy arthropods. Malagasy ectrichodiine specimens collected during this project allow for delimitation of new taxa, phylogenetic studies, divergence dating, and historical biogeographic investigations. Based on morphological characters, the Malagasy ectrichodiine fauna comprises more than 40 new species and a few new genera. The first molecular dataset (COI mtDNA, 28S D2-D5 rDNA) of Ectrichodiinae is assembled to test generic concepts. This dataset is subjected to divergence dating and biogeographic analyses to determine when Malagasy lineages originated and how these lineages arrived on the island (i.e., Gondwanan vicariance or dispersal). Results show that Malagasy Ectrichodiinae do not form a monophyletic group. Some Malagasy lineages are recovered as sister groups to Oriental or Afrotropical lineages.