Caledoniana alata, 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 : 3-4

Caledoniana alata sp. nov.

urn:lsid:zoobank.org:act:9B3A55AF-D726-41DA-AA96-B3D8B9836BC5

Figs 1A , 2 A–B; Table 1

Diagnosis

Colonies lightly fascicled basally, loosely branched, coplanar; nodes indistinct, internodes short; hydrothecae in opposite pairs and coplanar series; long, tubular, free part distinctly curved upward; gonothecae large, piriform.

Etymology

From the Latin ālātus, meaning "winged", making reference to the shape of the hydrothecae, recalling the wings of a gliding bird.

Type material

Holotype

NEW CALEDONIA: campaign Bathus 4, station DW923, 18°52’ S, 163°24’ E, 502– 470 m, 6 Aug. 1994; 3.6 cm high, branched fragment bearing a mature gonotheca (IK-2012-10287).

Paratype

NEW CALEDONIA: data as for holotype; 4.6 cm high, branched fragment bearing a mature and an immature gonotheca (IK-2012-10288).

Description

Two stem fragments, 3.6 and 4.6 cm high, with no hydrorhizae, possibly detached at base from same colony; lightly fascicled proximally, with a few accessory tubes creeping over main tube bearing hydrothecae. No evident division into internodes, even in monosiphonic parts. Each equivalent of internode short, accommodating pair of opposite, though not contiguous, hydrothecae. Single side branches, given off laterally from below a stem hydrotheca, occur in both specimens; structure similar to that of stem, except for first hydrotheca, which is unpaired. Hydrothecae large, tubular, immersed for about half their length into their corresponding internodes; free parts bent at nearly right angles to internodes, then curving upwards toward their middle; diameter nearly constant for most of length, slightly expanding toward aperture; rim with thickened perisarc; in frontal view, aperture semi-circular on adaxial side and somewhat flattened on abaxial side; a filmy, rounded operculum observed in one hydrotheca, but opercula likely deciduous. Gonothecae large and pyriform, with no distinct aperture; at least three large, globular structures (oocytes or young embryos) present in one of them. Numerous, large foramina (obliterated by thin pellicle of perisarc) below each hydrotheca suggest that gonothecae may occur in pairs in fully fertile specimens. Coenosarc badly preserved, not suitable for tentacle counting or cnidome studies.

Remarks

The hydrothecae are so large that sand grains partially or totally fill their lumina. In this case, the finding of an operculum closing the aperture of a hydrotheca is truly fortunate.

Figures

Fig. 1. A. Caledoniana alata gen. et sp. nov., holotype (below) and paratype (above). B. Caledoniana decussata gen. et sp. nov., colony silhouette (part of holotype). C. Caledoniana microgona gen. et sp. nov., colony silhouette (holotype). The red arrows indicate the presence of gonothecae. Scale bars: 1 cm.

Fig. 2. — A–B. Caledoniana alata gen. et sp. nov. A. Portion of fertile stem (note gonotheca above) and basal part of a side branch, showing positions of hydrothecae. B. Hydrotheca. — C–D. Caledoniana decussata gen. et sp. nov. C. Portion of stem with first and second order side branches from region of colony with coplanar hydrothecae, showing their relative position. D. Hydrotheca. — E–G. Caledoniana microgona gen. et sp. nov. E. Portion of stem. F. Hydrotheca. G. Three gonothecae. Scale bars: A, C, E, G = 3 mm; B, D, F = 1 mm.