Tulpa diverticula Totton, 1930

Watson, Jeanette W., 2003, Deep-water hydroids (Hydrozoa: Leptolida) from Macquarie Island, Memoirs of Museum Victoria 60 (2), pp. 151-180 : 173-174

Tulpa diverticula Totton

Figures 24A–D

Tulpa diverticula Totton, 1930: 145 , fig. 5.— Ralph, 1957: 844, fig. 7.— Millard, 1977a: 20, figs 5G–H.— Stepanjants, 1979: 35, pl. 6 fig 2.— Gravier-Bonnet, 1979: 33.— Bouillon et al., 1995: 86.

Campanularia diverticula Naumov and Stepanjants, 1962: 72 .— Dawson, 1992: 13.

Material examined. Stn 44, TM K2786, specimen alcohol-preserved, infertile colony on Eudendrium and other hydroids. Stn 90, TM K2788, specimen alcohol-preserved, sparse infertile colony on another hydroid. Stn 94, NMV F91326, specimen alcohol-preserved, NMV F91352 malinol-mounted microslide from same colony; infertile colony detached from substrate. Stn 119, TM K2787, specimen alcohol-preserved, sparse infertile colony on another hydroid. Stn 120, NMV F91327, sparse infertile colony, specimen alcohol-preserved.

Description. Colony stolonal, hydrorhiza tubular, perisarc smooth and thick with close, fine, vertical internal striae. Hydrothecal pedicels tubular, of variable length, given off more or less regularly, usually from same side of stolon; pedicel ending in a weak constriction below hydrotheca, sometimes 1 or 2 regeneration joints along length; perisarc thinner than on hydrorhiza.

Hydrotheca large, deeply cylindrical to weakly bell-shaped, base rounded with transverse diaphragm with central hydropore, wall thickened below diaphragm, thinning above. Hydrotheca gracefully everted below circular margin, rim with 12–14 shallow crenulations sometimes finely replicated, usually six to eight faint pleats extending partially or completely down into hydrotheca from embayments between crenulations. Hydranth large, with 20–24 tentacles.

Colour. Preserved specimens colourless. Measurements (µm)

Hydrorhiza diameter 280–380

Pedicel length 1900–4900 diameter 160–300

Hydrotheca diameter at diaphragm 220–340 length, diaphragm to margin 2320–2820 diameter of margin 820–1000

Distribution. North and South Islands of New Zealand ( Ralph, 1957) and Antarctic ( Stepanjants,1979).

Remarks. The straggling hydrorhiza readily detaches from the substrate. The thin hydrotheca is easily crushed along the pleatlines during mounting. Many pedicels are segmented with up to five regenerations, apparently repair after breakage. The species is a very common epizooite on other hydroids in the collection.

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.