Pacificincola perforata ( Okada and Mawatari, 1937 )

Min, Bum Sik, Chae, Hyun Sook, Yang, Ho Jin, Noh, Geon Woo & Seo, Dong Hee Lee and Ji Eun, 2021, A new species and new record of Pacificincolidae (Bryozoa: Cheilostomata) from Korea, Journal of Species Research 10 (3), pp. 276-286 : 279-280

Pacificincola perforata ( Okada and Mawatari, 1937)

( Fig. 2 )

Mucronella perforata Okada and Mawatari, 1937, p. 442 , pl. 11, fig. 8, text fig. 4a- c.

Hippoporina perforata : Huang et al. 1990, p 744, fig. 8, c.

Pacificincola perforata : Liu and Liu, 1999, p. 340, textfig. 1a- c, pl. 1, figs. 1-5; Liu et al., 2001, p. 572, pl. 44, figs. 1, 2; De Blauwe, 2006, p. 140, figs. 1-3; Grischenko et al., 2007, p. 1122 , fig. 30.

Material examined. Baengnyeongdo Island , 27 Nov. 2007 ; Incheon Port , 4 Sep. 2008; 1 Jul. 2010; 27 Jun. 2011; 25 Aug. 2012 ; Hagampo Beach , 13 Feb. 2009; 16 May 2010 ; Daebyeon Port , 30 Jun. 2009 ; Sinjindo , 26 Jul. 2009 ; Gwangyang Port , 16 Aug. 2009 ; Jodo Island , 4 May 2010 ; Hauido Island , 21 Jun. 2010 ; Jangsaengpo Port , 25 Jun. 2010; 24 Jun. 2011; 25 Feb. 2014 ; Jeju Port 28 Jun. 2010 ; Seogwipo Port , 28 Jun. 2010 ; Cheongpodae Beach , 12 Jul. 2010; 17 Feb. 2011 ; Ganggu Port , 24 Jun. 2011; 17 Jan. 2012 ; Gampo Port , 24 Jun. 2011; 3 Mar. 2015 ; Gangjeong , 10 Jul. 2011 ; Guryongpo Port , 22 Aug. 2012 ; Yangpo Port , 22 Aug. 2012 ; Hoenggyeongdo Island , 17 Apr. 2013 ; Suyabangdo Island , 14 Oct. 2013 ; Namae Port , 26 Feb. 2014; MABIK IV00170720 , 27 Feb. 2014 ; Sindo Island , 7 May 2020 .

Substratum. Rocks, stones, shells (oysters, bivalves, gas- tropods), calcareous tubeworm, seaweeds, plastics.

Description. Colony encrusting, coherent, greyish white, forming unilaminar patch, up to about 2 cm in diameter, light yellow color when alive. Zooids subhexagonal, elongate ovoid, or irregularly rectangular, 0.43-0.68 mm long (average 0.51± 0.07 mm), 0.23-0.39 mm wide (average 0.33± 0.04 mm), separated by a groove and suture line. All zooids of one type. Frontal wall slightly convex, granulated, evenly perforated with circular pores. Orifice semicircular, longer than wide, 0.09-0.15 mm long (average 0.12± 0.01 mm), 0.08-0.14 mm wide (average 0.12± 0.01 mm); wide shallow sinus laterally confined by a pair of pointed small triangular condyles. Peristome distinct lateral lappets, not developed distally, with proximal raised umbo and a small opening of kenozooid between umbo and orifice. Ovicell globose, prominent, hyperstomial, 0.21-0.24 mm long (average 0.23± 0.01 mm), 0.23-0.25 mm wide (average 0.25± 0.01 mm), closed by operculum, recumbent on frontal wall of distal zooid and partially overhanging orifice, frontally imperforate, irregular nodular, sometimes with finely tuberculate radiating ribs, with series of marginal pores. No spines and avicularia. Interzooidal communication via multiporous septu- la. Ancestrula elongate oval, 0.05-0.06 mm long (average 0.06± 0.01 mm), 0.08-0.09 mm wide (average 0.08±0.00 mm), similar to autozooids, frontal wall finely granulated and evenly perforated with numerous pores. Ancestrular orifice roughly circular. Ancestrula buds smaller zooids, two distolaterally and two laterally, surrounded by zooids.

Distribution. Japan (Yatarojima near Onagawa Bay, northern Honshu, 34 m in depth; Akkeshi Bay on the Pacific side of Hokkaido). China (Qingdao in Shandong Province; Shipu in Zhejiang Province; Pingtan Island, Xiamen, and Dongshan Island in Fujian Province; Daya Bay and Dapeng Bay in Guangdong Province, and Hong Kong and its neighboring waters, 0-15 m in depth), France (Bay of Arcachon), Netherlands (Goesse Sas in the Oosterschelde; Yerseke).

Remarks. According to Liu and Liu (1999), the width of orifice in Chinese specimen ranges from 0.07 to 0.11 mm (average 0.09± 0.02 mm), which is smaller than the one of European materials ( De Blauwe, 2006). On the other hand, the zooidal length and width from France are smaller than the others from the Pacific ( Table 2).

Ecology. This species is a fouling bryozoan which attaches to seaweeds, hydroids, rocks, stones, shells, buoys, fishing nets and synthetic materials. This is known to be one of the commonest bryozoan foulers in the coastal waters off the southern China seas ( Liu and Liu, 1999). Also in Korea, this species attaches to stones, oyster shells ( Crassostrea gigas ), bivalve shells ( Mytilus galloprovin- cialis), worm tubes, seaweeds, plastics from intertidal zone. Japanese specimens were found on seaweed, rock and bivalve shell only, not on the man-made substratum, such as fishing nets and buoys (Grischenlo et al., 2007). The East Pacific bryozoan Pacificincola perforata has been introduced to the Northeast Atlantic Ocean. The most likely route of introduction is via importations of pacific oysters ( Crassostrea gigas ). Its currently known distribution in the Atlantic is restricted to estuaries in France and the Netherlands ( De Blauwe, 2006). It can be expect- ed that Pacificincola perforata will rapidly spread on the Atlantic coast of Europe.

Figures

Fig. 2. Pacificincola perforata. (A) Baengnyeongdo Island, 27 Nov. 2008; (B, C) Sinjindo Island, 26 Jul. 2009; (D) Cheongpodae Beach, 12 Jul. 2010.A, zooids; B, orifice; C, ovicells; D, ancestrula and daughter zooids. Scale bars: A-D =0.10 mm.