Solenoscyphus candelabrum, Galea, 2015

Galea, Horia R., 2015, Two new genera and nine new species of hydroids (Cnidaria: Hydrozoa) from off New Caledonia, European Journal of Taxonomy 135, pp. 1-19 : 8-9

Solenoscyphus candelabrum sp. nov.

urn:lsid:zoobank.org:act:88847458-73D4-42B1-B553-4AD070BC2AFA

Figs 3A , 4 A–B; Table 2

Diagnosis

Colonies regularly pinnate, stems polysiphonic, cladia always monosiphonic; nodes indistinct; stem internodes composed of an apophysis, an axillary hydrotheca, two alternate hydrothecae above, another apophysis opposite to the former, and an axillary hydrotheca; cladial internodes, each with one hydrotheca; hydrothecae alternate throughout, long, tubular, free part distinctly concave, facing upward; operculum deciduous.

Etymology

From the Latin candēlābrum , meaning "candlestick", with reference to the shape of the hydrothecae, the whole colony resembling a phantasmagoric candelabrum with an infinity of arms. Used as a noun in apposition.

Material examined

Holotype

NEW CALEDONIA: campaign Bathus 4, station DW923, 18°52’ S, 163°24’ E, 502– 470 m, 6 Aug. 1994; 9.0 cm high, sterile colony (IK-2012-10292).

Paratypes

NEW CALEDONIA: data as for holotype; four sterile colonies 5.7–12.0 cm high (IK-2012-10293).

Description

Stems up to 12 cm high, arising from disc-shaped hydrorhizae firmly attached to substrate; strongly polysiphonic basally, uniformly grading to monosiphonic towards apices; auxiliary tubes running up, nearly parallel to main tube and establishing occasional anastomoses with each other. Nodes generally poorly indicated, though division into internodes with apparently unusual repetitive sequence: proximal node, short lateral apophysis (supporting a cladium), axillary hydrotheca, two alternate hydrothecae above, second cladial apophysis on opposite side to former, axillar hydrotheca, and distal node. Cladia pinnately arranged, given off at about 70° to stem, up to 3 cm long; straight, unbranched, exclusively monosiphonic; inserting on corresponding stem apophyses by means of short, rectangular, ahydrothecate internodes; nodes indistinct. Hydrothecae of both stem and cladia biseriate, alternate, and coplanar; tubular, S-shaped, facing out- and upward; a prominent internal perisarc thickening occurring along median line of lower half of abaxial wall, together with a transverse ridge arising from middle part of perisarcal thickening, and extending over both “frontal” and “dorsal” sides of theca; elsewhere perisarc relatively thin; in frontal view, aperture of hydrotheca rounded adaxially and slightly flattened abaxially; deciduous opercula rarely seen at apertures of some hydrothecae. Gonotheca unknown.

Figures

Fig. 3. A. Solenoscyphus candelabrum gen. et sp. nov., colony silhouette (holotype). B. Solenoscyphus decidualis gen. et sp. nov., colony silhouette (holotype). C. Solenoscyphus striatus gen. et sp. nov., colony silhouette (holotype). Scale bars: A = 2 cm; B–C = 1 cm.

Fig. 4. — A–B. Solenoscyphus candelabrum gen. et sp. nov. A. Portion of stem with basal parts of five cladia. B. Hydrotheca, showing internal projections of the perisarc. — C–D. Solenoscyphus decidualis gen. et sp. nov. C. Portion of stem with basal parts of two consecutive cladia. D. Hydrotheca. — E–G. Solenoscyphus striatus gen. et sp. nov. E. Portion of stem with basal part of a side branch. F. Hydrotheca, showing the characteristic striation of the perisarc. G. Operculum. Scale bars: A, C, E = 2 mm; B, D, F = 500 μm; G = 300 μm.