Watersipora mawatarii, Vieira & Jones & Taylor, 2014

Vieira, Leandro M., Jones, Mary Spencer & Taylor, Paul D., 2014, The identity of the invasive fouling bryozoan Watersipora subtorquata (d’Orbigny) and some other congeneric species, Zootaxa 3857 (2), pp. 151-182 : 171-174

Watersipora mawatarii n. sp.

( Figs 54–58 ; Table 4 )

? Dakaria typica Okada & Mawatari, 1937: 438 , pl. 11, fig. 6; text-fig. 2 [ Japan].

? Dakaria subovoidea: Kubota & Mawatari, 1985: 203 , fig. 4 [ Japan].

Material examined. Holotype: NHMUK 2012.6 .30.8, Oshoro Marine Station , near Otaru, Hokkaido, Japan, intertidal, 16 April 1996, M.J.Weedon coll. Paratypes: NHMUK 2012.6.30.9–11, same data as holotype ; NHMUK 2012.6.30.12–13, 17, Otaru chiko, Japan, on dead barnacles near shore, 12 December 1996 , T. Kato coll. NHMUK 2012.6.30.18, dry, Amakusa Marine Biological Laboratory , Kyushu, Japan, 40–50m, dredged, 22 October 1996, T. Kato coll.

Etymology. Named for Japanese bryozoologist Prof. Shunsuke F. Mawatari.

Description. Colonies encrusting, multiserial, uni- to multilamellar; sometimes erect, foliaceous and bilamellar; colour greyish to black in dead colonies. Zooids elongate-elliptical to rectangular, widest below the orificial area, about twice as long as wide, separated by slightly raised lateral walls; zooids arranged in quincuncial series. Frontal shield thick, granulated, slightly convex, with numerous small (10–15 µm diameter), round pseudopores covering entire surface except for suborificial region; two latero-oral intrazooidal septula, near lateral zooidal margin, proximolateral to orifice, each with 3–6 small pores. Frontal shield obscured by opaque, dark cuticle. Orifice large, transversely elliptical, usually conspicuoualy wider than long, with well-defined proximal broad sinus; orificial rim often thick and raised, but some zooids with thin, slightly raised rim; narrow bar-shaped condyles occupying entire proximal edge of orifice, sometimes projecting medially as triangular projection. Operculum black, mushroom-shaped; lucidae present. Avicularia absent. Ovicells absent.

Remarks. The overall zooidal morphology of specimens here figured and described resemble some Japanese specimens—viz. Dakaria typica Okada & Mawatari, 1937 (= Watersipora typica ) from Miyagi, and Dakaria subovoidea from Hokkaido ( Kubota & Mawatari 1985)—but they are distinguished by having fewer pseudopores in the frontal shield than Watersipora mawatarii n. sp. The thinner circular area in the distal half of the operculum, characteristic of W. typica , is also absent in W. mawatarii n. sp.

Watersipora mawatarii n. sp. resembles W. edmondsoni sensu Soule & Soule (1975) from Hawaii (the holotype of Watersipora edmondsoni belongs to Watersipora subtorquata , see above), characterized by its long zooids (about 0.80–1.20 mm long and 0.40–0.60 mm wide) and dark-brown mushroom-shaped opercular pigmentation, with a curved lower portion that fits into the sinus area. Soule & Soule (1975) also reported frontal shields with very small pseudopores like those of W. mawatarii n. sp. The shape of the zooids (widest below the orificial area) and the absence of pseudopores in the suborificial region were also described for some specimens from different Indo-West Pacific sites—Bali ( Winston & Heimberg 1986; as Watersipora edmondsoni ), Vanuatu ( Tilbrook et al. 2001; as Watersipora subovoidea sensu Harmer ) and Hawaii (Dick et al. 2006; as Watersipora subovoidea sensu Harmer )—which we believe belong to an undescribed species; these specimens differ from W. mawatarii n. sp. in having a narrower sinus and smaller orifice: 0.189–230 mm long and 0.238 –0.270 mm wide in W. mawatarii n. sp. versus 0.162 –0.216 mm long and 0.198 –0.234 mm wide in species from Bali ( Winston & Heimberg 1986), and 0.15–0.18 mm long and 0.20–0.25 mm wide in specimens from Hawaii (Dick et al. 2006).

Watersipora mawatarii n. sp. resembles W. subatra in having a U-shaped sinus, bar-shaped condyles, and two latero-oral intrazooidal septula. The two species differ, however, in the size of the pseudopores (smaller in W. mawatarii n. sp.) and condyles (more conspicuous in W. mawatarii n. sp.) and in the absence of pseudopores in the suborificial region (characteristic of W. mawatarii n. sp.).

Distribution. Japan.

Figures

FIGURES 54–58. Watersipora mawatarii n. sp., from Japan. 54–55, NHMUK 2012.6.30.8, holotype, Hokkaido; 54, autozooidal arrangement; 55, distal of an autozooid. 56–58, NHMUK 2012.6.30.13, paratype, Otaru; 56, autozooids; 57, closeup of an orifice and the two latero-oral intrazooidal septula; 58, close-up of the lateral edge of the orifice, showing a condyle and a latero-oral intrazooidal septulum.