Halecium jaederholmi Vervoort, 1972

Material examined: BBB 2016: St. 18; St. 23; St. 28; St. 32; St. 38. GARCÍA 2015: St. 17 (Fig. 2L) (MACN-In: 43473, 43474, 43475, 43476).

Distribution: The species had been reported in Atlantic Ocean, Argentinean continental shelf and subantarctic islands, from 41°S to 55°S by Jäderholm (1905, as Halecium arboretum), Vervoort (1972), Stepanjants (1979), Beshbeeshy & Jarms (2011). This is the first record at MPAs Namuncurá I and II.

Remarks: Big, fasciculate and fertile male and female colonies were found as basibionts of other hydroids, mainly hebellids and campanularid colonies. Synonyms at the area: Halecium jäderholmi (see Oliveira et al. 2016).