Diversity and taxonomy of intertidal Bryozoa (Cheilostomata) at Akkeshi Bay, Hokkaido, Japan Author Grischenko, Andrei V. Author Dick, Matthew H. Author Mawatari, Shunsuke F. text Journal of Natural History 2007 2010-07-29 41 17 - 20 1047 1161 http://dx.doi.org/10.1080/00222930701391773 journal article 10.1080/00222930701391773 1464-5262 5228835 Cauloramphus magnus Dick and Ross, 1988 ( Figure 10 ) Cauloramphus magnus Dick and Ross 1988 , p 36 , Plates 2F, 10C, 13B. Cauloramphus magnus : Grischenko 1997 , p 163 ; 2004, p 40; Dick et al. 2005 , p 3700 , Figure 2E–H . Cauloramphus cymbaeformis : Dick and Ross 1986 , p 89 . Cauloramphus spinifer : Kubota and Mawatari 1985a , p 80 , Figure 5 . Material examined ANC, ancestrular colony on rock (NHM 2006.2.27.32), colony on rock (NHM 2006.2.27.54), two extensive colonies on rock (NHM 2006.2.27.33–34); DIN, two colony fragments (NHM 2006.2.27.35). Additional material: 97 specimens ; also several colonies on stones from Oshoro Bay , Hokkaido , Sea of Japan . Description Colony up to 2.8 cm across, light yellow to tan when alive. Zooids ( Figure 10A–F ) 0.57– 0.80 mm long (0.67¡ 0.07 mm ), 0.32–0.48 mm wide (0.39¡ 0.04 mm ), separated by a distinct, shallow groove. Cryptocyst ( Figure 10E ) narrow, sloping, coarsely granulate. Gymnocyst mostly reduced, smooth; occasionally tapering back between preceding zooids. Opesia 0.37–0.53 mm long (0.44¡ 0.04 mm ), 0.20–0.30 mm wide (0.26¡ 0.03 mm ), with crenulate margin, occupying 70–90% of zooidal length. Around mural rim, 11–18 spines; five or six distal spines hollow, straight, thicker and blunter than the rest; proximal 6–12 spines considerably thinner, sharp, curved, arched over opesia, well separated, occasionally meeting in midline; in some zooids, most proximal spine erect, hollow, thicker and longer than others, similar in length to distal spines. Avicularia ( Figure 10D ) generally rare, usually single when present, originating from gymnocyst between proximal and distal spines ( Figure 10C, D ); slightly longer than distal spines, with relatively long, thin pedicel gradually expanding into heavy, slightly curved chamber with terminally facing rostrum; mandible triangular, directed laterally. Embryos brooded endozooidally; fertile zooids with a small kenozooidal ooecium ( Figure 10E ) occupying distal portion of mural rim. Six pore chambers in each lateral wall and three in distal wall. Ancestrula ( Figure 10F ) tatiform, elongate-oval, 0.42 mm long, with about 16 spines along opesial margin. Ancestrula buds triplet of small zooids distally and distolaterally, each with 8–12 spines; ancestrula surrounded by six zooids. Figure 10. Cauloramphus magnus Dick and Ross, 1988 . (A, C, D) NHM 2006.2.27.33–34; (B) NHM 2006.2.27.54; (E) NHM 2006.2.27.35; (F) NHM 2006.2.27.32. (A) Colony margin with developing zooids, unbleached; (B) same, bleached; (C) autozooids, unbleached; (D) close up of autozooids showing details of avicularia and spines, unbleached; (E) autozooids, bleached; (F) ancestrula and periancestrular zooids, bleached. Scale bars: 0.5 mm (A–C, E, F); 0.4 mm (D). Remarks Specimens from Hokkaido agree well with the original description ( Dick and Ross 1988 ) of C. magnus from Kodiak Island, Gulf of Alaska . Both zooidal and opesial sizes are similar, but the spine number is greater at Akkeshi (11–18 compared to 11–14); a population from Ketchikan, Alaska ( Dick et al. 2005 ) also had more spines (12–18) than material from the type locality. Distribution This is a Boreal Pacific species, reported in the eastern Pacific from Kodiak Island in the western Gulf of Alaska ( Dick and Ross 1988 ) and Ketchikan in southern southeast Alaska ( Dick et al. 2005 ). In the western Pacific, it has been reported from the Commander Islands ( Grischenko 1997 , 2004 ), though this material needs reexamination by SEM. We also collected this species at Oshoro Bay ( Hokkaido ), which is the southernmost known locality for C. magnus .