Halecium cf. delicatulum Coughtrey, 1876 (morphotype 1)

(fig. 3 E, F)

Halecium delicatulum Coughtrey, 1876: 26, pl. 3 figs 4–5. – Ralph, 1958 (pro parte): 334, figs 11E, H–N, 12A–K (not 12L–P = Halecium flexile Allman, 1888). – Schuchert, 2005: 629, fig. 12.

Material examined. Stn. T17, 06.iii.2005: two sterile stems arising from the same stolon, 3 and 8 mm high, respectively.

Description. Small colony composed of two monosiphonic, unbranched stems, arising from the same stolon. Stems geniculate, divided into long internodes by oblique nodes sloping alternately in opposite directions. Each internode with well-developed distal hydrophore, pointing upwards and surpassing level of node. Hydrothecae moderately deep, pseudodiaphragm present, margin flaring, everted, renovations common. Gonothecae absent.

Remarks. Although devoid of the characteristic female gonothecae, the present specimen fits the accepted concept of H. delicatulum, due to the geniculate appearance of stem, the morphology of internodes, hydrophores and hydrothecae, and the presence of a pseudodiaphragm. See also discussion under the next hydroid.

Distribution. Reportedly circumglobal in tropical, subtropical and boreal waters (Peña Cantero 2006). This is the first record of this species for Tristan da Cunha.