Watersipora subovoidea (d’Orbigny, 1852), d'Orbigny, 1852

Ryland, John S., Blauwe, Hans De, Lord, Richard & Mackie, Joshua A., 2009, Recent discoveries of alien Watersipora (Bryozoa) in Western Europe, with redescriptions of species, Zootaxa 2093, pp. 43-59 : 54

Watersipora subovoidea (d’Orbigny, 1852)

( Fig. 4 C, D, G, H)

Cellepora subovoidea d’Orbigny, 1852: 402 .

Lepralia cucullata Busk, 1854: 81 , pl. 96, figs 4, 5.

Schizoporella cucullata var. labiosa Calvet, 1903: 141 –142, pl. 16, fig. 7a–c.

Smittia (Watersipora) cucullata: Neviani 1895: 83 .

Lepralia ? cucullata: Waters 1909: 150 , pl. 15, figs 2–4 [pars].

Watersipora cucullata: Hastings 1930: 729 [pars], pl. 15, figs 97–101 (not 102–104); Soule & Soule 1976: 306, pl. 2, figs 1–2; pl. 3, fig. 1; pl. 4, fig. 3; also pl. 3, fig. 2, as Cellepora ovoidea , from Savigny’s (1817) plate.

[? Not] Dakaria subovoidea: Harmer 1957: 1022 , pl. 69, figs 11, 12, 14.

Watersipora subovoidea: Gautier 1962: 183 ; Ryland 1965: 68, figs 33c, d; 1974: 345, fig. 3A; Soule & Soule 1976: 302, pl. 3, fig. 4; pl. 4, fig. 4; Zabala 1986: 396, fig. 129; Hayward & McKinney 2002: 63, fig. 29A, B.

Material examined. All specimens are in the Natural History Museum, London. Naples, Italy, 20-10-1960, JSR (1 slide, intact, NHM 2007.12.14.2); Arrawarra, New South Wales, Australia, January 1772, JSR (3 slides: 1 cleaned, NHM 2007.12.14.3; 2 decalcified, NHM 2007.12.14.4–5) ( Ryland 1974); Port of Genoa, Italy, 12-11-2007, M. Faimali (3 slides: 1 cleaned, NHM 2007.12.14.6; 2 decalcified, NHM 2007.12.14.7–8).

Description. Colonies encrusting, unilaminar, multilaminar or sometimes foliaceous, brownish-purple to almost black in life (fading to grey when dried), with the growing margin orange. Zooids subrectangular or slightly hexagonal, sometimes narrower proximally (usually when associated with row division); large, distinct, about twice as long as wide, 700–1100 (mean ~900) × 350–650 (mean ~450) μm (globally; Table 2 ), variable within and between colonies. Frontal skeletal wall rather flat, perforated by numerous large round pseudopores 20–30 μm diameter; in some zooids two or more distal pores, largely concealed by the orificial rim, may be areolar septular pores; covered by a variably pigmented layer and a shiny, transparent cuticle. Orifice large, subcircular to oval, slightly wider than long; 200–250 (mean ~205) × 190–250 (mean ~230) μm; occupying <10% of the total zooid area; with a proximal sinus demarcated by the condyles, ~50 × 100 μm; surrounding rim variably elevated. Condyles triangular, projecting tooth-like distomedially into the anter (distal portion of orifice). Operculum strongly pigmented, with a broad, parallel-sided dark central band demarcated by sclerites, paler peripheral regions, and two white spots (lucidae) proximally, each adjacent to the condyle. 23–24 tentacles ( Waters 1909, Naples).

Variation and remarks. The rim of the orifice may be somewhat elevated on either side of the sinus, as in the form distinguished as var. labiosa by Calvet (1903, pp. 141, 142), from the intertidal of Graciosa, Azores. Waters (1909) confounded two species under his Lepralia cucullata ― his Naples specimens were correctly identified and are now therefore referred to W. subovoidea , but those from the Red Sea (Plate 15, figs 1, 5), later distinguished as var. watersi by Mawatari (1952), are clearly referable on the basis of the operculum to W. subtorquata .

Figures

FIGURE 4. Light photomicrographs of orifices and opercula of Watersipora. Scale bar = 100 Μm. A – D, orifices; E – H, opercula. A. W. subtorquata, St-Jacut-de-la-Mer, France; B. W. subtorquata, St Peter Port, Guernsey; C. W. subovoidea, Arrawarra, New South Wales, Australia; D. W. subovoidea, Genoa, Italy; E. W. subtorquata, St-Jacut-de-la-Mer, France; F. W. subtorquata, St Peter Port, Guernsey; G. W. subovoidea, Naples, Italy; H. W. subovoidea, Genoa, Italy. In A – D, note the differences in condyles (the left one in each picture arrowed); in E – H, compare the sides of the central dark band, concave in W. subtorquata, parallel in W. subovoidea.