Abstract The first species of syncarids described in 1847 were actually fossils from the Coal Age. More fossil species were described, but after 45 years, the first living syncarid was recognized in 1894. Molecule sequences revealed that mountain shrimp have little to do with bathynellaceans. They are classic caridoidans except for the lack of a carapace. Their biogeography indicates a Gondwana pattern—for example, Stygocaris has species in Victoria, New Zealand, and Chile. The fossil Anaspidacea (palaeocaridaceans), largely Carboniferous, were once thought of as a separate order, but recent cladistic analyses locate them within the living order. A Triassic species and a Cretaceous taxon provide a minuscule post-Carboniferous fossil record.