First record of Eutonina scintillans Bigelow, 1909 (Hydrozoa: Leptomedusae: Eirenidae) in temperate waters of the southwestern Atlantic Ocean

we herein report the leptomedusae eutonina scintillans (bigelow, 1909) for the buenos aires coast (38°s) as a consequence of a research project dealing with hydromedusae distributions in the southwestern atlantic ocean (34°-55°s). this is the first record of this species, which was previously known for tropical waters (brazil, 16°s), in the temperate waters of the south american atlantic ocean. possible reasons for its appearance so far south are discussed