Stegella lobata ( Vanhöffen, 1910 )

Soto, Joan J. & Peña, Álvaro L., 2019, Benthic hydroids (Cnidaria, Hydrozoa) from the Weddell Sea (Antarctica), Zootaxa 4570 (1), pp. 1-78 : 24-25

Stegella lobata ( Vanhöffen, 1910)

( Fig. 7 b–c)

Material examined. ANT XV/3: 48-4, few hydrothecae, c. 4 mm high, on dead octocoral; 48-5, one colony, c. 90 mm high, with gonothecae, and few hydrothecae, up to 3 mm high, on Sc. unifurcata ; 48-27, one colony, c. 60 mm high; 48-36, some stems, up to 20 mm high, on O. terranovae ; 48-44, some stems, up to 40 mm high, on polychaete tube; 48-44, one colony, c. 75 mm high, with gonothecae; 48-50, one colony, c. 60 mm high, on dead octocoral; 48-63, one colony, c. 60 mm high, with gonothecae; 48-77, one colony, c. 80 mm high, and few hydrothecae, c. 3 mm high, on Sy. weddelli ; 48-194, one hydrotheca, c. 5 mm high, on Sc. nana ; 48-197, some stems, up to 20 mm high, on B. subrufa ; 48-220, some stems, up to 120 mm high, on gravel and dead octocoral, with gonothecae; 48-276, few hydrothecae, up to 3 mm high, on Sc. nana ; ANT XVII/3: 111-9, one colony, c. 130 mm high, with gonothecae; 111-18, some hydrothecae, c. 6 mm high, on O. terranovae and Sc. nana ; ANT XXI/2: PS65/39, some stems, up to 110 mm high, on Sc. nana , with gonothecae; PS65/121, some stems, up to 70 mm high, on bryozoan, with gonothecae; PS65/132, one colony, c. 75 mm high; PS65/166, one hydrotheca, c. 2 mm high, on St. nonscripta ; PS65/175, some stems, up to 40 mm high, on B. subrufa and dead Oswaldella sp.; PS65/ 237, one colony, c. 110 mm high, on Sc. nana , with gonothecae, and few hydrothecae, c. 2 mm high, on Sy. exochus ; PS65/248, some stems, up to 40 mm high, on octocoral and H. incertus ; PS65/253, one colony, c. 60 mm high, on polychaete tube, with gonothecae; PS65/265, few stems, up to 5 mm high, on H. pseudodelicatulum ; PS65/276, one colony, c. 75 mm high, with gonothecae; PS65/281, one colony, c. 90 mm high, on sponge, with developing gonothecae; PS65/336, some stems, up to 30 mm high, on Sc. nana .

Remarks. Specimens analyzed have been observed using a wide range of basibionts as substrate (see above). Large colonies are seen in many cases overgrowing the basibiont almost completely. Stegella lobata seems to behave as an aggressive epibiont species that uses its host to reach large size. This relationship can be described as parasitism sensu lato, in which the epibiont is detrimental to the host but is not metabolically dependent upon it (see Gili et al. 2006 and literature cited).

Ecology and distribution. Previously collected at depths from 10 ( Naumov & Stepanjants 1972, as Stegella grandis ) to 700 m ( Naumov & Stepanjants 1962, as Stegella grandis ); present material was obtained from 62 to 417 m. Circum-Antarctic species (Peña Cantero et al. 2004).

Figures

FIGURE 7. a Lafoeina longitheca: hydrotheca. b–c Stegella lobata: b stem showing hydrothecal arrangement; c gonotheca. d Phialella belgicae: hydrotheca. e–h Campanularia hicksoni: e general view of the colony; f hydrotheca; g pioneer polyp showing planula attachment; h gonotheca. i–j Campanularia sp.: i hydrotheca; j developing gonotheca. k–m Billardia subrufa: k general view of a colony growing on Oswaldella erratum; l stem showing hydrothecal arrangement; m gonothecae.