Evolutionary biogeography and diversification of Ampithoidae (Crustacea, Amphipoda) in the southwestern Atlantic

The crustacean family Ampithoidae is one of the most abundant invertebrate families associated with macroalgae in shallow marine waters. Ampithoe , the largest genus, was previously documented as non‐monophyletic by phylogenetic analyses based on morphological and molecular characters. Here, we reconstructed a multi‐gene phylogeny of Ampithoidae with the first data of the southwestern Atlantic Ocean. We performed the first biogeographic analyses for the family, which indicated its origin in the Indo‐West Pacific, with subsequent dispersion to the Atlantic Ocean around the Eocene. Divergence times suggest that the diversification of Ampithoidae is congruent with the brown algae crown radiation, which allowed the colonization of new environments.