Plesiocleidochasma porcellaniforme (Soule, Soule & Chaney 1991)
- Dataset
- Taxonomy and diversity of coelobite bryozoans from drift coral cobbles on Co To Island, northern Vietnam
- Rank
- SPECIES
Classification
- kingdom
- Animalia
- phylum
- Bryozoa
- class
- Gymnolaemata
- order
- Cheilostomatida
- family
- Phidoloporidae
- genus
- Plesiocleidochasma
- species
- Plesiocleidochasma porcellaniforme
description
(Figs 14, 20 G)
description
Measurements. AzL, 0.37 – 0.47 (0.403 ± 0.025); AzW, 0.22 – 0.39 (0.306 ± 0.041) (n = 15, 1). OrL, 0.11 – 0.15 (0.131 ± 0.010); OrW, 0.089 – 0.115 (0.099 ± 0.007) (n = 15, 2). OvL, 0.17 – 0.22 (0.194 ± 0.015); OvW, 0.19 – 0.25 (0.221 ± 0.015) (n = 15, 1). Description. Colony unilaminar, encrusting, sheet-like; sometimes partly bilaminar due to self-overgrowth. Zooids small, boundaries indistinct. Frontal wall slightly convex, imperforate; surface weakly pustulose; often bearing several scattered, low, rounded nodules; with a few marginal pores, some of which may be positioned inside margin. Marginal zooids show three small spine bases, which are not evident in interior zooids. Orifice keyhole-shaped; anter circular or subcircular, separated by strong, proximomedially directed condyles from narrower, rounded poster. Frontal avicularia single or paired lateral or proximolateral to poster, although zooids lacking frontal avicularia not uncommon. When paired, avicularia directed at slightly different angles, one sometimes pointing laterally and other distolaterally. Avicularian rostrum rounded proximally, acute distally; crossbar complete or incomplete; opesial opening more or less arrowhead-shaped. Ooecium subimmersed, imperforate, same texture as frontal wall; opening covered by broad, flat labellum, with narrow transverse slit above, distinct lateral slits, and narrow transverse slit below that merges with lateral slits.
discussion
Remarks. This species was originally placed in the genus Schedocleidochasma Soule, Soule & Chaney, 1991 b, but Berning (2012), concluding that no clear boundary could be drawn between that genus and Plesiocleidochasma, declared the former a junior synonym of the latter.
distribution
Distribution. Widely distributed in the central to western Pacific, ranging from the Hawaiian Islands westward to Indonesia, Thailand, Vietnam, and the Maldives (Indian Ocean) (Soule et al. 1991 b; Tilbrook 2006; this study).
materials_examined
Material examined. VNMN- 0256 (CT- 7), VNMN- 0257 (CT- 8), VNMN- 0258 (CT- 13), VNMN- 0259 (CT- 15), VNMN- 0260 (CT- 29), VNMN- 0261 (CT- 31), on SEM stubs.