Hydractinia

Júnior, Miodeli Nogueira, 2012, Gelatinous zooplankton fauna (Cnidaria, Ctenophora and Thaliacea) from Baía da Babitonga (southern Brazil), Zootaxa 3398, pp. 1-21 : 10-11

Hydractinia sp.1

(Fig.25)

Material examined: 10/18/2007 —12 medusae; 11/16/2007 —18 medusae; 01/24/2008 —14 medusae; 02/29/ 2008 —197 medusae; 04/25/2008 —one medusa; 05/25/2008 —five medusae; 08/08/2008 —two medusae ( MZUSP 1597).

Description. Medusae bell-shaped, varying from 0.5 to 1.2 mm in diameter with thin mesoglea. Manubrium tubular, without peduncle, occupying nearly half the length of bell cavity. Four mouth lips prolonged into simple small oral tentacles. Eight well-developed tentacular bulbs without ocelli. Gonads well-defined along the interradial walls of the manubrium.

Remarks. The characters and general appearance of these medusae are quite similar to Hydractinia carnea (Sars) ( Kramp 1959a, 1961; Edwards 1972; Bouilon et al. 2004), however detailed morphological (including both polyp and medusa stages) and molecular characterization being conducted (Bettim 2010; Haddad et al. 2010; M.A. Haddad & A.L. Bettim unpublished data) indicate this is a new species.

Distribution. Known from Paranaguá (Bettim, 2010; Haddad et al. 2010) and Babitonga (present study) estuaries. Endemic to south Brazilian estuaries (?).