A new southern record of the holopelagic annelid Poeobius meseres Heath, 1930 (Flabelligeridae).

Using molecular phylogenetic analysis of a newly-collected specimen from the Salas y Gómez Ridge off Chile, we extend the known geographic range of P. meseres southwards by 2040 km. This subtropical specimen showed higher genetic similarity to a specimen from the type locality (< 1.5% pairwise COI distance) than to representatives from the Aleutian Islands and Japan (5-6%), establishing the first genetically-confirmed occurrence of this species in the Southern Hemisphere. The latitudinal range of P. meseres encompasses the sole collection locality, off Ecuador, of Enigma terwielii Betrem, 1925, a pelagic annelid which has been compared to P. meseres, but is indeterminable due to an inadequate description. We therefore suggest that the earlier sole record of E. terwielii may have been an occurrence of what is known now as P. meseres.