Freshwater Bryozoa of Okinawa, Japan, with descriptions of Rumarcanella gen. nov. (Phylactolaemata: Plumatellidae) and two new species Author Hirose, Masato Author Mawatari, Shunsuke F. text Zootaxa 2011 2732 1 19 journal article 10.5281/zenodo.276554 ec9d7b62-108f-45a6-bb9b-d1c9565c00fa 1175-5326 276554 Plumatella javanica Kraepelin, 1906 ( Figure 3 ) Plumatella javanica Kraepelin, 1906 : 143 , figs 1–3; Annandale 1910 : 42 , 50; 1911: 221; Toriumi 1952a : 267 ; Wiebach 1964 : 12 , figs 4–8, pl. 1(4,) pl. 2(5–7), pl. 3(8–12), pl. 4(13); 1967: 77, pls 1, 2(1–8); 1970, 356, pl. 1(4a, 4b, 5a, 5b); Lacourt 1968 : 72 , pl. 15(j); Rao 1973 : 529 ; 1976, 339, fig. 4H; Rao et al . 1985 : 261 ; Smith & Wood 1995 : 362 , fig. 1; Wood & Wood 2000 , 423, fig. 1; Wood et al . 2006 : 14 , figs 20–21, 36. Plumatella emarginata var. javanica : Loppens 1908 : 162 . Material examined. Mature colony with floatoblasts from Fukuji Dam, village of Higashi. Description. Observed colony light brown or reddish brown, its surface encrusted ( Fig. 3 A); almost entirely recumbent, with pronounced keel, ends of branches often rising from substratum ( Fig. 3 B). Tentacle number about 45. Floatoblast elliptical in our specimen, large, about 340–410 (366±38) μm long by 180–236 (215±31) μm wide (n=3) ( Fig. 3 C); length/width ratio about 1.8. Fenestrae of floatoblast large; in SEM view, surface entirely covered with minute, rounded tubercles that are rounded-hexagonal in outline, with 5–8 (average 6) small, irregular pores in the angles ( Fig. 3 D). Ventral fenestra 200–246 (225±23) μm long by 182–211 (194±15) μm wide; dorsal fenestra about 150–180 (174±10) μm long by 130–160 (139±16) μm wide (n=3). Floatoblast valves asymmetrical in lateral and transverse views, the ventral valve strongly convex and dorsal valve almost flat. Suture line of both valves with a simple ridge. Sessoblast also with tuberculate surface ( Wood et al . 2006 ). Distribution. Distributed mainly in tropical regions ( Bushnell 1973 ), including Southeast Asia ( Lacourt 1968 ; Wood et al . 2006 ), central Africa ( Wiebach 1964 ), and the Amazon River in South America ( Wiebach 1967 , 1970 ). This is the first record of P. javanica from Japan , where it occurs on Okinawa and the Pacific side of southern Honshu (Ibaraki, Tokyo, and Kochi Prefectures). Remarks. Kraepelin (1906) originally described P. javanica from Indonesia . Previous authors have considered statoblast morphology, colony color and colony form as important diagnostic characters of this species. Annandale (1911) reported a transparent, glassy ectocyst and a strong raphe, and Smith & Wood (1995) also indicated these characters. However, as with other plumatellid species, these characters vary ecophenotypically; for example, Annandale (1911) specifically mentioned variation in the form of colonies attached to dead wood. Like P. javanica , P. vorstmani (see below) also has a transparent ectocyst, but the tentacle number in P. j a v a n i c a is almost twice that in P. vorstmani , and statoblast size and morphology are different.