Monotheca togata ( Watson, 1973 )

Watson, Jeanette E., 2011, Review of the genus Monotheca (Hydrozoa: Leptolida) from Australia with description of a new species and a note on Monothecella Stechow, 1923, Memoirs of Museum Victoria 68, pp. 71-91 : 86

Monotheca togata ( Watson, 1973)

Fig. 6 A–I

Plumularia togata Watson, 1973: 191 , figs 65–67.— Bouillon et al., 2006: 371.— Stranks, 1993: 14.

? Monotheca togata . — Vervoort and Watson, 2003: 374, fig. 91A– E.

Material examined. NMV F42060 , holotype, microslide (malinol mounted), Pearson Island , South Australia, on red alga Metagoniolithon charoides , depth 33 m, coll: S. Shepherd 8 January 1969. Paratypes: microslides NMV F42061 , F42062 , F42063 , F4 G2064, F42065, F42066,F42105 ; SAMH40 ,PearsonIslandonredalga Metagoniolithon charoides , coll: S. Shepherd, 8 January 1969 .

Description. Hydrorhiza a network of broad, flat stolonal tubes with internal flexion joints. Stems short, to 4 mm long, monosiphonic, with one to three short basal internodes, nodes transverse, succeeding internodes moderately long and slender, expanding distally to a broad shoulder at apophysis, a strong transverse septum above and below node at level of apophysis, distal node V-shaped, sometimes a weak transverse septum about halfway up internode near level of cauline nematotheca.

Apophysis short, robust, just below distal cauline node, slightly frontal on stem, upwardly directed, abcauline wall a continuation of internode, adcauline wall set close to internode, distal end wide, thickened, node transverse, a weak oblique internal septum below node.

Hydrocladia alternate, one on cauline internode, slightly forwardly directed, athecate internode very short, corrugated, a strong transverse internal septum, distal node transverse. Hydrothecate internode much longer than athecate internode, inserted into shoulder of athecate internode with a slender V-shaped joint; internode downwardly curved below hydrotheca.

Hydrotheca cowl shaped (lateral view), scoop shaped (anterior view), with a distinctly peaked adcauline margin (i.e. opposite base of hydrotheca), prehydrothecal chamber short, inflated, upper (adcauline) wall strongly convex, sometimes a faint septum passing from internode into base, hydrothecal margin hemispherical to triangular (anterior view), in lateral view adcauline wall extending in a peak over margin; rim thickened and outrolled.

Nematothecae bithalamic, moveable, all similar in shape but differing slightly in length of base, cup robust, wide and fairly shallow, adcaudally excavated almost to base; one cauline, about halfway along internode on same side as apophysis, one axillar beside apophysis, one median inferior on hump of prehydrothecal chamber, just reaching base of hydrotheca, twin laterals standing close together at either side of a low distal protuberance of internode, bases short, sides facing inwards to hydrothecal margin; in lateral view, nematothecae appear to be almost inside hydrothecal margin.

Male gonotheca large, inserted on a short, straight pedicel beside apophysis on first stem internode, body barrel shaped, distally truncated, walls smooth to weakly undulated, aperture terminal, transverse, closed by a sheet of tissue. Female gonotheca unknown.

Figures

Figure 6. A–I, Monotheca togata. A, stem; B, part of stem showing internodes; C, slightly oblique ventral view of hydrotheca; D, full ventral view of hydrotheca, both views showing twin lateral nematothecae; E, apophysis of stem with proximal hydrocladium; F, gonotheca; G, cauline nematotheca; H, median inferior nematotheca; I, one of twin lateral nematothecae. Scale bar: A, F, 1 mm; B, 0.3 mm; C–I, 0.1 mm.