Plumatella repens ( Linnaeus, 1758 )

Hirose, Masato & Mawatari, Shunsuke F., 2011, Freshwater Bryozoa of Okinawa, Japan, with descriptions of Rumarcanella gen. nov. (Phylactolaemata: Plumatellidae) and two new species, Zootaxa 2732, pp. 1-19 : 7

Plumatella repens ( Linnaeus, 1758)

( Figure 2 E)

Tubipora repens Linnaeus, 1758: 790 ; Allman 1844b: 74; 1851: 330; Jullien 1885: 100, figs 16–68; Braem 1890: 2, pl. 1(4, 5, 7), pl. 2(21); Toriumi 1955a: 51, pl. 1(1–42); Wood et al. 1998: 642, figs 7, 11; Mukai 1999: 56, figs 2B, 3E, 5B, 7 B. Wood & Okamura 2005: 59, 89, figs 29b, 30, 31, 52.

Material examined. Floatoblasts from pond in city of Uruma; floatoblasts from Kurashiki Dam, city of Okinawa; colony with floatoblasts, Benoki Dam, village of Kunigami.

Description. Observed colony tubular, branching, light or yellowish brown; almost entirely recumbent, with ends of branches usually swollen; surface encrusted. Tentacle number 32–64. Floatoblasts in our material oval, 353–378 (366±6) μm long by 235–272 (256±11) μm wide (n=10), with length/width ratio of about 1.4. Fenestra of floatoblast almost circular; surface of fenestra covered with rounded tubercles; annulus smooth ( Fig. 2 E); valves almost symmetrical in lateral view. Sessoblast fenestra also covered with tubercles; annulus weakly reticulate ( Wood & Okamura 2005).

Distribution. Plumatella repens is common, and broadly distributed worldwide; distributed from Okinawa to Hokkaido in Japan.

Remarks. The colony and statoblasts of Plumatella repens vary environmentally, and the floatoblast is the commonest gross morphological type among plumatellids. Accordingly, other species with similar gross floatoblast morphology (e.g. P. fungosa and P. rugosa may have been misidentified as P. repens before SEM was used for observations.

Figures

FIGURE 2. SEM micrographs of statoblasts from three phylactolaemate species from Okinawa. A, Plumatella casmiana Oka, 1907, floatoblast, dorsal view. B, Plumatella casmiana, sessoblast. C, Plumatella emarginata Allman, 1844, floatoblast, ventral view. D, Plumatella mukaii Wood, 2001, floatoblast, ventral view. E, Plumatella repens (Linnaeus, 1758), floatoblast, dorsal view. Scale bars: 100 μm.