Figularia japonica Silén, 1941

Yang, Ho Jin, Seo, Ji Eun, Min, Bum Sik, Grischenko, Andrei V. & Gordon, Dennis P., 2018, Cribrilinidae (Bryozoa: Cheilostomata) of Korea, Zootaxa 4377 (2), pp. 216-234 : 225-227

Figularia japonica Silén, 1941

(Figs 28–29)

Figularia figularis: Okada & Mawatari 1935: 138 , pl. 10, fig. 6; Mawatari: 1963: 8. Non Lepralia figularis Johnston, 1847 . Figularia figularis var. japonica Silén, 1941: 115 , figs 174–177.

Reginella (Figularia) fissurata: Liu et al. 2001: 524 , pl. 34, fig. 3. Non Figularia fissurata Canu & Bassler, 1929 . Figularia figularis japonica: Hirose 2010: 90 , pl. 151A–B.

Material examined. W of Cheongsan Island, South Sea (two colonies) and Munseom Island, Seogwipo, Jeju Island (four colonies).

Description. Colony encrusting, unilaminar, multiserial, up to 32 mm across. Autozooids subrectangular. Autozooidal frontal shield comprising 7–10 (mostly 8–9) costae, pinnate except for suboral pair, the latter broader, fusing in midline, the rest triangular, their opposing tips interdigitating. 1–3 tiny lacunae between adjacent costae. Each costa with large, incised, proximal pseudopore (Fig. 29). Gymnocyst surrounding costal field, widest proximolaterally. Orifices dimorphic, longer and proportionally broader in female zooids. Autozooidal orifice somewhat parallel-sided, with broad, concave poster and short angular condyles. No oral spines. Avicularia large, subvicarious to fully vicarious (Fig. 28); rostrum weakly trilobate, with moderately sized rostral shelf and variably triangular foramen; crossbar separating rostrum from semicircular opesia that is bordered by smooth cryptocyst. Ooecium longer than wide, slightly larger than maternal costal shield, glabrous, with thin median suture line and two pairs of large ectooecial fenestrae (Fig. 28). Interzooidal communications via mural septula, not basal porechambers. Ancestrula not seen.

Measurements. ZL, 414–509 (465) µm; ZW, 303–343 (318) µm; OrL, 132–145 (141) µm; OrW, 133–162 (147) µm; AvL 377–465 (415) µm; AvW 110–178 (153) µm; OoL 257–307 (280) µm; OoW 299–353 (324) µm.

Remarks. We here raise the subspecies to full species. Silén (1941) described this taxon from Tokyo Bay. He remarked on the unusual doubling of the paired ectooecial fenestrae in the ooecium. The present material shows how this is achieved (Fig. 29). A few ooecia have a single very large fenestra on each side of the suture line and some others have a partial division of the large fenestra, achieved by a fold of calcification that grows from the lateral margin towards the median suture, bisecting the fenestra. Another species that can have two pairs of ectooecial fenestrae is Figularia fissurata Canu & Bassler, 1929 , described from east of Leyte Island, Philippines at about 10.77° S, but this character is inconsistent—some of the ooecia in the published illustrations (retouched) have only one pair, as confirmed in the species description. Further, Canu & Bassler (1929) depicted the costal pseudopores as being near the distal tips of the costae, not the proximal ends, and, whereas the avicularian opesia is small in F. fissurata , it is large in F. japonica , sometimes achieving more than half the size of the autozooidal orifice. Silén (1941) thought it unlikely that F. japonica was conspecific with F. fissurata and we agree. On the other hand, Liu et al. (2001) identified Chinese material as conspecific with F. fissurata , but it is clear from their SEM illustrations that they had F. japonica ; each costal pseudopore is in the proximal expanded part of the costa and the avicularian opesia is proportionately much larger than in F. fissurata , which appears to be a strictly tropical species.

Distribution. Southern Korea, Japan, China, 20–115 m.