Monotheca pulchella ( Bale, 1882 )

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 : 83

Monotheca pulchella ( Bale, 1882)

Fig. 4 F–L

Plumularia pulchella Bale, 1882: 30 , pl. 15, figs 6, 6a.— Bartlett,

1907: 43.— Stranks, 1993: 13. — Watson, 1994: 67.

Not Plumularia pulchella . — Bedot, 1921: 28.— Trebilcock, 1928: 24. — Totton, 1930: 221, fig. 58 a–d.— Hodgson, 1950: 41, fig. 71.— Ralph, 1961b: 39, fig. 5 c–e.— Blanco, 1973: 73, figs 1–3.— Millard, 1975: 398, fig. 125 C–D.— Izquierdo et al., 1986: 54, fig. 5.— Genzano, 1990: 50, figs. 16–17.— Medel and Vervoort, 1995: 58, fig. 25.— Vervoort and Watson, 2003: 369, 373, fig. 90J–L.— Bouillon, et al., 2004: 172, fig. 92G–K.

? Plumularia pulchella .— Blackburn, 1942: 108.— Day et al., 1952: 404.— Millard, 1957: 232.— Millard, 1962: 300.— Pennycuik, 1959: 180.— Ralph, 1961b: 109.— Millard, 1966: 493.— Berrisford, 1969: 394.— Day et al., 1970: 14.— Millard, 1978: 196.— Millard, 1980: 133.— Medel and López-González, 1996: 202.

Monotheca pulchella . — Stechow, 1921: 260.— Watson and McInnes, 1999: 111.

Material examined. NMV F59054, Bale collection, Museum Victoria, one microslide, labelled in Bale’s handwriting ‘ Plumularia pulchella Bale, Queenscliff , November, 1878’.

Material in author’s collection: microslide and preserved material, Knobbies Island, Western Port, on brown alga, coll: J. Watson, depth 10 m, 27 January1985.

Description. Hydrorhiza flat and ribbon-like with flexion joints. Stems monosiphonic, straight to weakly sympodial, basal athecate region with several transverse nodes often with one or two nematothecae, succeeding cauline internodes variable in length, cylindrical, robust, nodes deep, transverse to oblique, internode typically with several internal septa imparting a wrinkled appearance to stem.

Hydrocladia alternate, usually in one plane, but sometimes one or two forwardly displaced, halfway to one-third distance up internode, apophysis of stem upwardly directed away from internode, long, stout, with a broad transverse distal shoulder, usually an internal septum behind shoulder; hydrocladium short, athecate internode variable in length, proximal end narrow, inserted into shoulder of apophysis. Hydrothecate internode variable in length, almost entirely occupied by hydrotheca, proximal end of internode a narrow neck inserted into athecate node; distal end terminating in a protuberance behind hydrothecal margin.

Hydrotheca cup shaped, adcauline wall convex, immersed in internode, abcauline wall weakly concave and thickened; margin circular, transverse.

Nematothecae bithalamic, moveable, cauline and hydrocladial median inferior of same size and shape, base long and conical, cup deep, rim circular, slightly adcaudally shortened; a nematotheca one-third distance up cauline internode and two axillar; hydrocladial median inferior seated on a prominence of internode, just reaching base of hydrotheca, twin laterals seated almost at end of internode, base fairly short, cup adcaudally excavated.

Male and female gonothecae borne on same stem. Sexes of same shape, kidney shaped to ovoid, inserted on a smooth, short, bent pedicel at base of apophysis, pedicel expanding and merging into body of gonotheca; walls of gonotheca thick, smooth to faintly rugose, aperture distal, circular, displaced to one side, rim slightly thickened, a submarginal row of large, irregularly shaped inwardly directed lobate cusps, usually one or two larger than the others. Mature female gonophore containing a large ovum.

Figures

Figure 4. A–E, Monotheca obliqua. A, part of stem; B, hydrocladium and hydrotheca; C, female gonotheca; D, twin lateral nematothecae; E, axillar nematotheca and hydrostatic pore. Scale bar: A, C, 1 mm; B, 0.2 mm; D, E, 0.1 mm. F–L, Monotheca pulchella. F, part of stem; G, hydrocladium and hydrotheca; H, female gonothotheca with ova; I, anterior view of gonothecal aperture with internal lobate submarginal cusps. J, median inferior hydrocladial nematotheca. K, one of twin lateral nematothecae. L, axillar nematothecae. Scale bar: A,C, 1 mm.; B, 0.2 mm; F, H, 0.5 mm; D–E, I–L, 0.1 mm.