Celleporina porosissima Harmer, 1957

Grischenko, Andrei V., Dick, Matthew H. & Mawatari, Shunsuke F., 2007, Diversity and taxonomy of intertidal Bryozoa (Cheilostomata) at Akkeshi Bay, Hokkaido, Japan, Journal of Natural History 41 (17 - 20), pp. 1047-1161 : 1140-1142

Celleporina porosissima Harmer, 1957

( Figure 38 )

Celleporina porosissima Harmer 1957, p 906 , Plate 62, Figures 3 , 16 , 17 .

Celleporina porosissima: Voigt and Cook 1983, p 53 , Plates 1–3; Ikezawa and Mawatari 1993, p 1031, Figure 2A–L .

? Myriozoum marionense var. irregulatum Okada 1923, p 231 , Figures 27–31 .

? Myriozoum marionensis irregulatum: Okada 1934, p 19 ; Okada and Mawatari 1935, p 142, Plate 10, Figure 5 .

Material examined

ACT, four colonies detached from undetermined red algal rhizoid (NHM 2006.2.27.102).

Description

Colony encrusting, discoid, domed; a typical colony measured 1.5 by 1.2 by 0.2 cm; with multilayered arrangement of zooids, one over the other; light orange when alive. Colony surface undulating, with many knob-like lobes. Zooids at colony margin ( Figure 38A ) decumbent. As colony rises from substrate, zooids ( Figure 38B ) become erect, cylindrical, 0.28–0.38 mm across (0.33¡ 0.03 mm), haphazardly orientated. All zooids have numerous spinous processes within the zooidal cavity ( Figure 38A, B ). Frontal wall of decumbent zooids smooth, convex, with a few marginal pores and imperforate central area; in erect zooids, pores carried towards orifice by tubular extensions and form ring around peristome. Primary orifice ( Figure 38B ) oval, 0.12–0.18 mm long (0.15¡ 0.01 mm), 0.11–0.16 mm wide (0.14¡ 0.01 mm), submerged with age by peristome, with flattened condyles on condylar shelves and deep, U-shaped proximal sinus. Orifice of non-ovicellate zooids encircled by narrow peristomial lip; peristome enclosed by thickened proximal orificial lip and columnar lateral orificial avicularia, one on each side lateral to orifice, rarely single or absent; avicularian column stout, curved inward, often submerged with age; rostrum circular, terminal, angled almost perpendicular to orificial plane, with a complete cross-bar; semicircular mandible directed in a lateral direction. Vicarious avicularia ( Figure 38D ) scattered over colony surface, numerous in central colony region, 0.13–0.29 mm long, with spatulate mandible; cross-bar complete, rostral opesia large, sometimes with extensive palatal shelf and high rostral rim. Ovicell ( Figure 38C, D ) globose, 0.24–0.33 mm long (0.29¡ 0.02 mm), 0.29–0.39 mm wide (0.34¡ 0.03 mm), initially prominent, subimmersed with age; tabula semicircular, crescentic, or triangular, extensive, occupying nearly entire frontal surface of ovicell, bordered with radially arranged slit-like pores; secondary calcification results in a distinct border surrounding tabula. Ancestrula and early astogeny not observed.

Remarks

Okada (1923) was apparently the first person to collect this species, but described his material from the Korea Strait as a new variety, irregulatum, of Myriozoum marionense Busk, 1884 . Harmer (1957) recognized Okada’s form as different from M. marionense , and on the basis of specimens from Japan described it as a new Celleporina . A key diagnostic character is the common occurrence in young zooids of several rows of pores distal to the orifice, which was well illustrated by Ikezawa and Mawatari (1993, Figure 2A, C ) in their redescription of C. porosissima ; these authors also described the early astogeny. The deepwater specimens described by Okada (1923) formed colonies with erect, cylindrical, anastomosing branches, whereas Harmer (1957) described colonies as ‘‘small pleurilaminar crusts’’, and Ikezawa and Mawatari (1993) described them as ‘‘encrusting, discoidal, domed’’. Although Harmer (1957) attributed this difference in growth form to his specimens possibly having been in an initial stage of growth, the difference raises the question whether Celleporinna porosissima is indeed synonymous with Okada’s (1923) Myriozoum marionense var. irregulatum .

Distribution

Originally collected from depths of 90–200 m in the Korea Strait (if Harmer’s 1957 synonymy is valid), this species has been reported from the vicinity of Shimoda, Shizuoka Prefecture as colonies attached to seaweeds ( Okada 1934), and from Oshoro Bay,

Hokkaido, as colonies on fronds of Laminaria religiosa ( Ikezawa and Mawatari 1993) . Akkeshi Bay is the northernmost known locality .

Figures

Figure 2. Dendrogram (below) showing similarity of sampling localities based on species presence/absence, and a map (above) showing the geographical distribution of three groups of sampling localities (circled) that are less than 70% similar in species composition between groups.

Figure 3. Electra korobokkura Nikulina, 2006. (A–C) NHM 2006.2.27.1; (D) NHM 2006.2.27.2. (A) Colony fragment with uniserial branches; (B) colony fragment with anastomosing, multiserial branches; (C) zooids without spinous processes; (D) zooids with spinous processes. All unbleached. Scale bars: 2 mm (A, B); 1 mm (C); 0.5 mm (D).

Figure 5. Electra asiatica n. sp. (A, G) NHM 2006.2.27.19; (B) NHM 2006.2.27.20; (C, D) NHM 2006.2.27.21; (E, F) NHM 2006.2.27.24. Colony from Ptichiy Island, Sea of Okhotsk (H). (A, B) Colonies radiating in coherent, fan-shaped lobes from the point of origin, unbleached; (C) colony margin with developing zooids, unbleached; (D) astogenetically mature zooids, unbleached; (E) astogenetically mature zooids, bleached; (F) astogenetically mature zooids with a small interzooidal kenozooid (lower right quadrant), bleached; (G) ancestrula and periancestrular zooids; enlargement of ancestrular area seen in panel (A), unbleached; (H) astogenetically mature zooids, bleached. Scale bars: 2 mm (A, B); 0.5 mm (C–H).

Figure 16. (A, B) Bugula pacifica Robertson, 1905. NHM 2006.2.27.15. (A) General view of colony fragment, unbleached; (B) zooids, showing distal spinous projections and avicularia, unbleached. (C–F) Tricellaria occidentalis (Trask, 1857). (C) NHM 2006.2.27.48; (D–F) NHM 2006.2.27.49. (C) General view of colony fragment, unbleached; (D) basal surface of branch with kenozooids (rhizoids or radicle fibres), unbleached; (E) internode with immature zooids, unbleached; (F) abraded internode containing mature zooids with ovicells, unbleached. Scale bars: 1 mm (A); 0.5 mm (B, D, F); 2 mm (C); 0.4 mm (E).

Figure 17. Cribrilina annulata (Fabricius, 1780). (A) NHM 2006.2.27.50; (B, C) NHM 2006.2.27.51; (D) NHM 2006.2.27.52. (A) Zooids with developing secondary layer of dwarf zooids, from region nearly colony margin; (B) immature zooids; (C) autozooids densely covered with numerous ovicellate dwarf zooids; (D) ancestrula with periancestrular zooids. Scale bars: 0.5 mm.

Figure 27. Schizoporella japonica Ortmann, 1890. (A, D–G) NHM 2006.2.27.87; (B, C) NHM 2006.2.27.85; (H) NHM 2006.2.27.86. (A) Developing zooids at colony margin; (B) immature zooids; (C) zooids with developing ovicells; (D) mature zooids with oral and frontal avicularia directed laterally and distally; (E) mature zooids, showing details of orifice and avicularia; (F) ancestrular region. Scale bars: 0.5 mm (A–D, F); 0.4 mm (E).

Figure 28. Stomachetosella decorata n. sp. (A) NHM 2006.2.27.92; (B, E, F) NHM 2006.2.27.90; (C, D) NHM 2006.2.27.89. (A) Colony margin with developing zooids; (B) zooids with developing ovicells close to colony edge; (C) immature zooids; (D) mature zooids with immersed ovicells; (E) mature zooids with immersed ovicells, infundibular occluded frontal pores and scattered umbones; (F) ancestrular region. Scale bars: 0.5 mm.

Figure 29. Myriozoella plana (Dawson, 1859). (A) NHM 2006.2.27.79; (B–E) NHM 2006.2.27.81; (F) NHM 2006.2.27.82. (A) Differentiating zooids near colony margin; (B) immature zooids; (C) two zooids with developing ovicells; (D) zooids with almost completed ovicell flanked distally by three vicarious avicularia; (E) mature zooids with deeply immersed ovicells; (F) ancestrula and periancestrular zooids. Scale bars: 0.5 mm.

Figure 30. Pacificincola perforata (Okada and Mawatari, 1937). (A, D) NHM 2006.2.27.75; (B, C, F) NHM 2006.2.27.76; (E) NHM 2006.2.27.60. (A) Colony edge with differentiating zooids; (B) immature zooids; (C) orifice of immature zooid, showing minute sharp condyles and suboral umbo with central cavity; (D) zooids with developing ovicells; (E) two mature zooids with completed ovicells; (F) ancestrula and periancestrular zooids. Scale bars: 0.5 mm (A, B, D, E); 0.1 mm (C); 0.4 mm (F).

Figure 31. Cheilopora sincera (Smitt, 1868). (A, B) NHM 2006.2.27.77; (C, D) NHM 2006.2.27.78. (A) Zooids differentiating at colony margin; (B) immature zooids; (C, D) mature zooids with ovicells. Scale bars: 0.5 mm (A, B, D); 1 mm (C).

Figure 38. Celleporina porosissima Harmer, 1957. NHM 2006.2.27.102. (A) Developing zooids at colony margin; (B) immature zooids, showing form of primary orifice; (C) abraded mature zooids with subimmersed ovicells; (D) heavily calcified and abraded zooids and vicarious avicularium. Scale bars: 0.5 mm.