Margaretta tenuis Harmer, 1957

Chae, Hyun Sook, Kil, Hyun Jong & Seo, Ji Eun, 2016, Taxonomic study on bryozoans - new additions to the Korean fauna and new species of Petraliella from Seogwipo waters of Jeju Island, Journal of Species Research 5 (3), pp. 551-565 : 560

** 46. Margaretta tenuis Harmer, 1957

나IJÑnjḇNj (신ḡ) ( Fig. 5 )

Margaretta tenuis Harmer, 1957: 840 ; Hayward, 1988: 330.

Material examined. NIBRIV0000325944, Marado Is., 14 Nov. 2010 (B.S. Min) by SCUBA diving from 15­30 m in depth

Substratum. Rocks.

Description. Colony erect, branching, alternate whorls of 3 zooids and comprising jointed segments. Internodes delicate, 3­6 mm long and 0.3­0.6 mm in diameter. Zooids ( Fig. 5A ) oval, not distinct by suture lines, 0.70­ 1.02 × 0.26­0.32 μm, frontal wall regularly and evenly perforated by sunken pores. Peristome moderate projecting, distinctly ridged, usually straight, oblique, sometimes slightly curved distally. Orifice circular, surround­ ed by beads­like protuberances. Basis rami tripartite ( Fig. 5B ). Basal side with 3 zooids and 3 primary chitinous tubes ( Fig. 5D ). Ascopore ( Fig. 5C ) circular, situated in middle of frontal surface. Basal side with 3 zooids and 3 primary chitinous tubes. No avicularia or spines.

Remarks. The genus Margaretta Gray, 1843 from Korea includes two species, M. cereoides (Ellis and Solander, 1786) and M. tenuis Harmer, 1957 .

Distribution. Korea, Philippine, Australia.

Figures

Fig. 5. Margaretta tenuis Harmer, 1957. A. zooids. B. basis rami. C. ascopore. D. transverse section of zooids. Scale bars: 100 μm (A­D).