Cranosina coronata ( Hincks, 1881 )

Dick, Matthew H., Ngai, Nguyen Danh & Doan, Hung Dinh, 2020, Taxonomy and diversity of coelobite bryozoans from drift coral cobbles on Co To Island, northern Vietnam, Zootaxa 4747 (2), pp. 201-252 : 209

Cranosina coronata ( Hincks, 1881)

( Fig. 4A, B )

Membranipora coronata Hincks, 1881, p. 147 , pl. 10, fig. 1.

Setosellina coronata: Harmer 1926, p. 265 , pl. 16, figs 2 – 4.

Cranosina coronata: Tilbrook 2006, p. 25 , pl. 2e; Taylor & Tan 2015, p. 12, fig. 6; Dick & Grischenko 2017, p. 63, fig. 6e, f. For other synonyms and records, see Harmer (1926) and Tilbrook (2006).

Material examined. VNMN-0215 (CT-5), on SEM stub; VNMN-0216, four colony fragments.

Measurements. AzL, 0.49–0.65 (0.573 ± 0.048); AzW, 0.32–0.50 (0.409 ± 0.047); OpL, 0.19–0.48 (0.391 ± 0.071); OpW, 0.15–0.27 (0.212 ± 0.033); AvRL, 0.08–0.22 (0.178 ± 0.036); AvRW, 0.09–0.18 (0.122 ± 0.028) (n = 15, 1).

Description. Colony unilaminar, encrusting, sheet-like.

Zooids distinct, delineated by deep groove; often widest at, or proximal to, middle. Cryptocyst extensive, comprising wide, rounded mural rim, granulated on sides and top, with coarse ridges perpendicular to opesia on inside of mural rim; mural rim smooth laterally and distally in opercular region. Opesia extensive, often irregular in outline.

Avicularium distal to each zooid, distal end of rostrum forming semi-cylindrical channel to house setose mandible, directed laterally or slightly distolaterally. Spines lacking.

Ooecia lacking; zooids use internal sac for brooding.

Distribution. This species is broadly distributed in the Indo-West Pacific region, occurring from East Africa and the Red Sea to Indonesia, the Great Barrier Reef, New Guinea, Singapore, Malaysia, Vanuatu, the Solomon Islands, Vietnam, the Philippines, and Japan ( Chimonides & Cook 1994; Tilbrook et al. 2001; Tilbrook 2006; Taylor & Tan 2015; Dick & Grischenko 2017; this study).

Figures

FIGURE 4. A, B. Cranosina coronata (Hincks, 1881), VNMN-0215. A. Part of colony. B. autozooids and avicularia. C–F. Antropora minor (Hincks, 1880). C. Young colony with ancestrula (asterisk), partly overgrown by the foraminiferan Planorbulina larvata (bottom) and forming stand-off with it (upper left), VNMN-0218. D. Autozooids and avicularia, VNMN-0217. E. Autozooids and avicularia, with left-center autozooid having vestigial ooecium, and several autozooids having smooth, raised prominence (gymnocystal papilla) at proximal end, VNMN-0217. F. Non-ooeciate autozooid (left-center), ooeciate autozooid (lower right), and vicarious avicularium (upper right), VNMN-0276. Scale bars: A, C, 1 mm; B, 500 µm; D, 300 µm; E, 150 µm; F, 200 µm.