Calamphora quadrispinosa, Watson, 2003

Watson, Jeanette W., 2003, Deep-water hydroids (Hydrozoa: Leptolida) from Macquarie Island, Memoirs of Museum Victoria 60 (2), pp. 151-180 : 168-169

Calamphora quadrispinosa sp. nov.

Figures 18A–E

Material examined. Stn 94, NMV F91325, holotype, specimen alcohol-preserved, NMV F91346 malinol-mounted microslide from holotype, large colony on Symplectoscyphus . Stn 44, TM K2783, paratype, small colony on Eudendrium , specimen alcohol-preserved. Stn 120, NMV F91324, paratype, colony on Symplectoscyphus paulensis , specimen alcohol-preserved. Stn 130, TM K2784, paratype, on dead coral fragment, specimen alcohol-preserved. Stn 46, TM K2785, small colony on Eudendrium , specimen alcohol-preserved.

Description (of holotype and paratypes). Stolonal colonies tangled amongst host hydroids. Stolons simple, tubular, smooth, perisarc moderately thick, smooth to undulated, firmly attached to host, becoming free at intervals as monosiphonic stems, sometimes sparingly branched.

Hydrothecae pedicellate, arising singly, more or less regularly along one side of stolon or branch; hydrothecae upright or inclined at various angles, barrel-shaped or slightly asymmetrical (depending upon angle of view), body narrowing a little below margin, walls smooth to weakly undulated, usually in proximal third; body narrowing into a tubular pedicel; diaphragm thick, transverse to slightly oblique, hydropore central, circular, with short upturned collar. Margin transverse to axis, quadrate, distinctly everted with four broad, sharply pointed cusps separated by low embayments. Operculum of 4 thin triangular valves; in immature hydrothecae valves meet in a low upturned flange decreasing in height from hydrothecal margin to centre; in mature hydrotheca remnants of valves meeting in a central, ragged, upturned tuft. Perisarc of hydrotheca moderately thick proximally, thinning distally.

Hydranth (preserved material), columnar, with c. 16 tentacles and a wide, annular hypostome; no diverticulum or annular fold but a long bifid ligament issuing from below tentacle ring, joining hydrothecal wall in distal third.

Gonothecae arising from stolon, usually beside a hydrotheca; pedicel short, thick; mature gonotheca barrel-shaped, body with six to nine deep flanges, deepest in distal third, shallower proximally; aperture a dome of tissue surrounded by four long, equidistant, more or less inwardly curved spines. Sex of gonophores could not be determined.

Colour. White (preserved material); may have been pale yellow in life.

Measurements (µm)

Stolon-stem diameter 192–216

distance between hydrothecal pedicels 1060–1040 Hydrotheca length pedicel, adcauline side 64–224

length diaphragm to margin 1100–1280

maximum width 506–561

diameter at diaphragm 184–216

diameter at margin 440–480

height of marginal cusp 70–80 Gonotheca length of pedicel 120–176

distal width of pedicel 160–200

maximum diameter 520– 640

depth of ridges 68–100

width across margin 208–240

height of marginal cusps 76–120

Etymology. Named for the four claw-like spines of the gonotheca.

Remarks. There are no nodes in either the hydrorhizal or free stolons, only infrequent constrictions marking probable sites of breakage and repair. The free stolons (branches) are predominantly monosiphonic with some tendency to polysiphony by fusion of two stolons over short distances. The branches are usually loosely curved, and this together with adherence of the stolons to the substrate results in considerable tangling around the stems and branches of the hydroid host. The hydrothecae are usually single but occasionally two may be given off from opposite sides of the branch. Although the hydropore is centrally located, the base of the hydranth sometimes appears to be attached beside, rather than through the hydropore; a ring of large granules (seen in partially cleared specimens) marks the site of attachment. The operculum is retained after eruption of the hydranth and becomes torn into apical tufts presumably from repeated movement of the hydranth. This difference between the flanged operculum of immature hydrothecae and the fragmented tufts of mature hydrothecae is striking, and if the two forms were not present on the same colony the hydrothecae could easily be mistaken for two different species. The bifid ligaments supporting the extended hydranth are visible only when the hydranth is retracted. Nematocysts present in the tentacles and coenosarc of the stolons could not be identified. The colonies are abundantly fertile, the claw-like marginal spines of the gonotheca being characteristic. As no ova were seen in the gonophores the sex is presumed to be male.

Genera considered were: Sertularella Gray, 1848 , Thyroscyphus Allman, 1877 , Symmetroscyphus Calder, 1986 and Calamphora Allman, 1888 . Sertularella was rejected as the specimen has no clear abcauline diverticulum; as the material is stolonal Thyroscyphus was rejected; Symmetroscyphus was also rejected as the hydrotheca of that species is symmetrical.

Calamphora is said to possess a diverticulum situated on the adhydrorhizal side of the hydranth ( Millard, 1975) which in a stolonal colony is assumed to be the adcauline side. No evidence of such a structure was found in the present material; it is possible however, that from some angles of view, strands of ligament in inadequate material could be mistaken for diverticula.

Although Vervoort (1968) considered Calamphora to be inseparable from pedicellate Sertularella it nevertheless seems useful to retain the genus for exclusively pedicellate sertulariid species.

Calamphora quadrispinosa is the most abundant species in the collection.

Figures

Figures 18A–E. Calamphora quadrispinosa sp. nov., stn 94. A, three stems, part of colony. B, stem, enlarged. C, hydrotheca with intact flanged operculum. D, hydrotheca with ragged opercular valves after eruption of the hydranth; ligaments connecting hydranth to wall of hydrotheca. E, gonotheca. Scale bar: A, 10 mm; B, 1 mm; C, D, E, 0.5 mm.