Plumularia

Galea, Horia R., 2008, On a collection of shallow-water hydroids (Cnidaria: Hydrozoa) from Guadeloupe and Les Saintes, French Lesser Antilles, Zootaxa 1878, pp. 1-54 : 46-47

Plumularia sp.

(fig. 9J)

Material examined. Stn. 2: 01.04.2008 —several sterile stems, up to 8 mm high, on green algae and sponge. Stn. 3: 26.01.2008 —several sterile plumes, up to 10 mm high, on sponge; 01.04.2008 —numerous sterile stems, up to 8 mm high, on sponge and concretions. Stn. 7: one colony composed of numerous sterile stems, up to 6 mm high, on Halimeda sp.

Description. Monosiphonic, unbranched stems, up to 10 mm high, arising from creeping hydrorhiza. Basal part, of variable length, devoid of both cladia and nematothecae. Remainder of caulus regularly divided into internodes by means of transverse nodes; internodes 255–355 µm long, 80–105 µm wide in mid region, 70–95 µm wide at nodes. Perisarc thick and brown basally, becoming gradually thinner and transparent distally. Each internode with a latero-distal apophysis and two nematothecae: one axillar and one median, on side opposite to apophysis; cauline nematotheca 60–75 µm high; occasionally a transverse septum on proximal part of segment. Cladia alternate, nearly coplanar, borne on stem apophyses by means of short segment; the latter devoid of both hydrotheca and nematotheca; proximal end transverse, distal end oblique; with one internal, transverse septum in middle. Remainder of cladium heteromerously segmented; with up to 4 hydrothecate segments; the latter 145–200 µm long, with proximal node oblique and distal node transverse; one internal septum on proximal end; one hydrotheca placed in middle and 3 nematothecae: one median inferior, not reaching base of hydrotheca, and a pair of laterals, largely surpassing the hydrothecal rim, occasionally reaching distal end of segment. Hydrotheca cup-shaped, 75–85 µm deep, adcauline wall completely adnate; free abcauline wall straight; aperture circular, rim even, diameter 100–105 µm. Ahydrothecate segments, 275–340 µm long, with proximal node transverse and distal node oblique; two internal septa, on both ends of segment; one nematotheca on upper side, in middle part. All nematothecae inverted-conical, bithalamic; basal chamber higher than upper one. Gonothecae not seen.

Remarks. This species closely resembles P. s e t a c e a ( Linnaeus, 1758) and P. strictocarpa Pictet, 1893 , both with well-documented records from the western Atlantic ( Migotto 1996, Calder 1997). However, only the fertile material of these species is reliably identifiable (Millard 1975). Therefore, the present specimens could not be assigned to any of them, pending the discovery of additional, fertile material.