Nolella cf. papuensis ( Busk, 1886 )

Seo, Ji-Eun, Chae, Hyun Sook, Winston, Judith E., Zágoršek, Kamil & Gordon, Dennis P., 2018, Korean ctenostome bryozoans-observations on living colonies, new records, five new species, and an updated checklist, Zootaxa 4486 (3), pp. 251-283 : 264

Nolella cf. papuensis ( Busk, 1886)

( Fig. 8 )

Cylindroecium papuense Busk, 1886: 38 , pl. 8, fig. 2.

Nolella papuensis: Harmer 1915: 53 , pl. 4, figs 10–20; Rho & Kim 1981: 61, pl. 4, figs 1, 2; Rho & Seo 1986: 33; Seo 2005: 283, pl. 14, fig. 23

Material examined. MBRBK 1705 , 9 May 2017, Munseom Island offshore of Seogwipo Harbor , Jeju Island, 20 m.

Description. Colony forming chain or network of narrow cylindrical zooids. Zooid tubes varying in length, straight to slightly curved, connected by very narrow stoloniform elongations; zooids brown, opaque, their cuticle covered by particles of sediment proximally ( Fig. 8A, B ), the distal ends of zooids usually lighter and more translucent ( Fig. 8D ), with fine annular rings and topped distally by the often-squared orifice ( Fig. 8E, F ). Mean zooid length 1.043 mm (range 0.97–1.09 mm, N = 3); zooid width, mean 0.186 mm (range 0.145–0.217, N = 3), no dilation in diameter at base. Tentacle crown equitentacled, tentacles thin, straightly held; the one tentacle crown that expanded in our study ( Fig. 8C ) had 12 tentacles. No evidence of reproduction in colonies found.

Remarks. The muddy-looking cylindrical zooids of Nolella resemble tubes of polychaetes or amphipods, but their squared-off orifice is diagnostic, distinguishing them as belonging to Nolella . The zooids of the specimens collected in this study are shorter than the average for zooids of N. stipata recorded in Florida (2.1 x 1.8 mm zooid length and width) ( Winston 1982) and Brazil (2.3 x 1.8 mm) ( Vieira et al. 2014). Korean material collected previously and identified as Nolella papuensis had zooids 1.0– 2.8 mm long and 0.20–0.30 mm wide ( Seo 2005).

Harmer’s (1915) account of Nolella papuen sis from the Siboga Expedition reported considerable variability in zooid length depending on state of growth and/or regeneration, but able to attain almost 4 mm in height with a tentacle crown of c. 18 tentacles. Busk’s (1886) original description gave much smaller dimensions (1.3 x 0.10–0.11 mm). We believe the Korean specimens (all three from the South Sea), most closely approach N. papuensis . Embryos were lacking in our material, but embryos in colonies from other areas are brooded, several in a row, in the distal half of zooid tubes.

Distribution. Indonesia, New Guinea. Korea: Goheung, South Sea; Seogwipo, Jeju Island; intertidal to 20 m.

Figures

FIGURE 8. Nolella cf. papuensis (Busk, 1886), Seongsan port, Jeju Island (MBRBK1706). A. Live colony attached to shell substratum. B. Cylindrical, translucent to opaque zooids. C. Single tentacle crown of Nolella (next to asterisk) between two larger tentacle crowns of a stolonate hydroid colony. D. Zooids at the edge of a cheilostome colony. E. Compound-microscope image of distal end of Nolella zooid showing striated cuticle. F. Same, showing portions of three zooids, with squared orifice at the distal end of the middle zooid tube. Scale bars: A = 2 mm; B, D = 1 mm; E, F = 0.20 mm.