Bicrisia edwardsiana ( d’Orbigny, 1841 )

Chae, Hyun Sook, Yang, Ho Jin & Seo, Bum Sik Min and Ji Eun, 2023, Three new records of Korean cyclostomatous bryozoans, Journal of Species Research 12 (4), pp. 362-367 : 365-366

3. Bicrisia edwardsiana ( d’Orbigny, 1841) ( Fig. 4 )

Crisidia edwardsiana d’Orbigny, 1841: 8 .

Bicrisia edwardsiana : Borg, 1926: 351; Osburn, 1953: 676; Gordon, 2016: 605; Branch and Hayward, 2007: 5.

Material examined. Korea: Jeollanam-do: Wando-gun, Chenogsando Island , 25 July 1981, depth 15 m ; Jeju-do: Seogwipo-si, Gapado Island, 16 June 1985; Sangchujado Island , 22 July 1990 ; Jeollanam-do: Yeosu-si, Geomundo Island , 16 June 2020, depth 20 m.

Substratum. Other bryozoan and seaweed.

Description. Colony erect, articulated branching, small, delicate, slender, curved forward ( Fig. 4A, D ). Branch ramified at first zooid. Internodes narrowing proximally, beginning with one zooid, two to four zooids, only one internode of six; sterile internodes short, 443 - 743 (588± 11) μm long, alternately situated two to four zooids; fertile internode comprising three zooids, 493 - 564 (528±49) μm long ( Fig. 4A, B ). Zooids forward, 76 - 186 (117±4) μm long × 67 - 76 (70±4) μm wide, slender, elongate peristome, slit-shaped pseudopores, with numerous jointed spines arising at base side of peristome ( Fig. 4B, C ). Aperture circular, 38 - 61 (48±8) μm diameter. Gonozooid placed at second zooid, erect, oval, slit-shaped pseudopores, longer than wide, 336 - 365 (351±20) μm long × 199 - 248 (223±33) μm wide ( Fig. 4A, C ). Ooeciostome oval, short, bent, located at near distal end on dorsal, facing forward ( Fig. 4C ). Dorsal surface with slit-shaped pseudopores and transverse lines, constricted, curved inward ( Fig. 4D ).

Remarks. Korean B. edwardsiana is characterized by the gonozooid situated in the second zooid, always ramified from the first zooid, the forward bent ooeciostome near the distal end on the dorsal side of the gonozooid, and the jointed spines arising at base of peristome. The locations of the gonozooid and ooeciostome are important characteristics in identifying the species of the genus. In Osburn’ description, a characteristic feature of B. edwardsiana is “the position of the ooeciostome on the dorsal side near the distal end” ( Osburn, 1953), which agrees well with our materials.

All of six species of Bicrisia have been recognized: B. abyssicola Kluge, 1962 ; B. biciliata (MacGillivray, 1869) ; B. edwardsiana ( d’Orbigny, 1841) ; B. erecta Mawatari & Mawatari, 1973 ; B. gibraltarensis Harmelin, 1990 ; and B. robertsonae Soule, Soule & Chaney, 1995 ( Chae et al., 2018; www.bryozoan.net/cyclostomata/crisiidae/bicrisia. html - 21 July 2023). Bicrisia edwardsiana is close to B. erecta from Japan in the shape and location of the gonozooid is distinguished from B. erecta by the forward facing ooeciostome on gonozooid and by fertile internodes comprised of three zooids. Furthermore, B. edwardsiana has characteristics in common with B. biciliata from Australia in the shape of the gonozooid and the location and shape of the ooeciostome. The colony of both species always branches from the first zooid. B. biciliata differs in the location of the gonozooid, which replaces the third zooid.

The materials of Chenogsando Island and Sangchujado Island lacks gonozooids, but the shape of colonies and autozoid, the number of autozooid per internode, and the position of spine us to consider it B. edwardsiana .

Distribution. Korea (South Sea and Jujudo Island) and widespread.

Figures

Fig. 4. Bicrisia edwardsiana (d’Orbigny, 1841). A, Colony showing autozooidal arrangement with gonozooid; B, Internodes and jointed spines; C, Gonozooids and ooeciostomes; D, Dorsal surface. Scale bars:A =1 mm; B-D=500 μm.