Abstract
During 2007,2008, and 2010,23 specimens of an undescribed vermiform sea anemone were collected on Punta Pardelas and Fracaso Beach (Peninsula Valdes, Argentina). The specimens have longitudinal rows of cinclides distally, all mesenteries perfect, tentacles hexamerously arranged without acrospheres, column not divisible into regions, no marginal sphincter and no conchula. We describe these specimens as a new species within the genus Harenactis (family Haloclav-idae). Harenactis argentina sp. nov. is the second species of Harenactis; it represents the first record of this genus in the southern hemisphere and the first record of a soft bottom-dwelling sea anemone in the Argentine continental zone. Furthermore, we discuss the familial placement and relationships of the genus Harenactis and other athenarian sea anemones.
NSTL