Solenoscyphus decidualis, 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 : 9

Solenoscyphus decidualis sp. nov.

urn:lsid:zoobank.org:act:E4FDE6E2-065E-43CC-B978-126563826AA9

Figs 3B , 4 C–D; Table 2

Diagnosis

Colonies regularly pinnate, stems polysiphonic, cladia always monosiphonic; nodes indistinct; stem internodes composed of two alternate hydrothecae, an apophysis, and an axillary hydrotheca; cladial internodes each with one hydrotheca; the latter alternate, long, tubular, free part slightly convex basally, then straight; operculum deciduous.

Etymology

From the Latin dēcĭdŭus, meaning "deciduous", with reference to the condition of the hydrothecal operculum.

Material examined

Holotype

NEW CALEDONIA: campaign Biocal, station DW38, 23°00’ S, 167°15’ E, 360 m, 30 Aug. 1985; 4.0 cm high, sterile colony (IK-2012-10294).

Description

Essential part of hydrorhiza missing, but remains of what appears to be a rhizoid stolon, firmly attached to substrate, could be seen. Colony erect and pinnate, ca. 4 cm high. Stem lightly fascicled basally, grading to monosiphonic distally; auxiliary tubes fused to one another, forming outer layer of perisarc enveloping main tube; monosiphonic part of stem with indistinct nodes; equivalents of internodes composed of proximal “node”, two alternate hydrothecae, short lateral apophysis (supporting cladium) on side opposite to second hydrotheca, axillary hydrotheca, and distal “node”. Cladia up to 1.2 cm long, inserted on corresponding stem apophyses, occurring at an angle of about 70° with stem; nodes indistinct; equivalents of internodes relatively short, each carrying a hydrotheca on its distal half. Hydrothecae of both stem and cladia biseriate, alternate, given off at 70–75° to “internodes”; tubular, adnate for onefourth of adaxial length; both free adaxial and abaxial walls parallel, imperceptibly convex to almost straight; rim even, aperture circular, placed at right angle to axis of theca; rare, rounded opercula close 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.