Campanularia hicksoni Totton, 1930

Watson, Jeanette W., 2003, Deep-water hydroids (Hydrozoa: Leptolida) from Macquarie Island, Memoirs of Museum Victoria 60 (2), pp. 151-180 : 174-175

Campanularia hicksoni Totton

Figures 24E–G

Campanularia hicksoni Totton, 1930: 148 , figs 7a–e.— Briggs, 1938: 15.— Rees and Thursfield, 1965: 90, 195.— Blanco and Bellusci de Miralles, 1972, 145: 10, figs 6–19.— Naumov and Stepanjants, 1972: 34, 37.— Stepanjants, 1972: 67, fig. 12.— Stepanjants, 1979: 29, pl. 5 fig. 1.— Blanco, 1984: 18, pl. 13 figs 29–31.— El Beshbeeshy, 1991: 94, fig. 22a.—Blanco, 1994: 159.

Campaularia laevis Hickson and Gravely, 1907: 25 , pl. 4 fig. 26.— Ritchie, 1913: 19, fig. 5.— Vanhöffen, 1910: 298, fig. 18 (not Campaularia laevis Hartlaub, 1905: 565 , fig. P1).

Material examined. Stn 44, TM K2792, NMV F91331, infertile colonies on Tulpa diverticula and Eudendrium , specimens alcohol-preserved.

Description. Colonies comprising many pedicellate hydrothecae arising from hydrorhiza overrunning stems and hydrorhizae of other hydroids. Stolons tubular, sometimes contorted, perisarc thick. Pedicels simple, unbranched, variable in length, long, tubular, of same diameter as stolon; most pedicels with 3 or 4 obscure proximal annulations, pedicels thereafter smooth, sometimes with a few groups of undulations or joints marking site of regeneration. Pedicel ending in a slightly expanded distal shoulder, a flattened spherule between stem and basal chamber of hydrotheca.

Hydrotheca deeply campanulate, walls expanding smoothly from base to margin, basal chamber narrow, enclosed by outer walls, diaphragm marked by an annular thickening of wall; margin circular, crenulate, with 8–10 apically flattened cusps, embayments between U-shaped, an almost exact reverse image of cusps. Hydrothecal margins often with 2 or 3 widely separated regenerations. Hydranth with c. 16–18 tentacles.

Perisarc of stems fairly thick, thinning distally along hydrothecal body to margin.

Colour. Colonies transparent and colourless to white.

Measurements (µm)

Pedicel length 1200–3800

diameter 64–72

diameter of spherule 52–64 Hydrotheca depth of basal chamber 40–64 length, diaphragm to margin 640–664 diameter at margin 320–440 height of marginal cusp 40 width of marginal embayment 48–64

Distribution. Antarctic ( Totton, 1930; Briggs, 1938; Stepanjants, 1979).

Remarks. Many hydrothecal margins are damaged and most of the undamaged ones fade in stained mounts The few faint pleats extending downwards from the margin in many hydrothecae may result from collapse in mountant.

Dimensions of the present specimens agree fairly well with those of the “short race” of Campanularia hicksoni recorded from a depth of 92 m from McMurdo Sound ( Totton, 1930) but with the following minor differences: (i) the hydrothecae of the present specimens are a little more campanulate than shown in Totton’s figure; (ii) overall length of the hydrotheca of the present specimens is at the lower range of Totton’s specimens; and (iii) the marginal diameter of the present specimens falls between Totton’s “short race” and those he considered normal for specimens from Cape Adare. Totton’s specimens had a variable number of marginal crenulations (9–20); the number of crenulations on the present specimens are at the lower end of this range .

Figures

Figures 24A–G. A–D, Tulpa diverticula, stn 94. A, stem from colony. B, hydrotheca, C, rim of hydrotheca, enlarged, D, base of hydrotheca, enlarged. E–G, Campanularia hicksoni, stn 44. E, hydrotheca. F, base of hydrotheca showing thickening and diaphragm. G, rounded marginal cusps. Scale bar: A, 10 mm; B, 1 mm; C, D, 0.5 mm; E, F, G, 0.5 mm.