Walkeria prorepens Kubanin, 1992

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 : 270

Walkeria prorepens Kubanin, 1992

( Fig. 14 )

Walkeria prorepens Kubanin, 1992: 21 , fig. 2.

Material examined. MBRBK 1705 . Seongsan Port , Jeju Island, 33.4690° N, 126.9260°E, 8 May 2017, intertidal.

Description. Colony forming delicate network made up long narrow stolons with autozooids budded from short perpendicular kenozooid chains ( Fig. 14E ). Zooids perpendicular or oblique to stolon; distance between zooid clusters on stolon about 0.5 mm. Zooids narrow, elliptical, pointed at their proximal origin, with expanded center and a narrow quadrate distal orifice. Zooid length, mean 0.260 mm (range 0.188–0.301 mm, N = 4); zooid width, mean 0.058 mm (range 0.041–0.074 mm, N = 4). Zooids separated from kenozooidal stolon by a short peduncle. Stolon width c. 0.027 mm. Cuticle of zooid tubes relatively thick, hence zooids not sagging like those of some Amathia . Frontal surface in young zooids semitransparent and slightly granulated. Autozooids budded from subterminal frontal position on kenozooid; first as two lateral buds, later one terminal bud. Polypides with 8 tentacles and campylonemidan tentacle crown in which two tentacles are bent away from other six ( Fig. 14B–D ). No evidence of reproduction in our material.

Remarks. Our material best fits the species described by Kubanin (1992) from Peter the Great Bay on the Russian coast of the Japan Sea. This author provided a table of the Walkeria species then known, regarding Walkeria prorepens as most similar to W. uva ( Linnaeus, 1758) from the North Atlantic but differing from it in stolon length, size, and mode of budding of zooids from kenozooids.

Distribution. Korea: Jeju Island, on intertidal rock. Russian coast of the Japan Sea, on Amathia rudis .

Figures

FIGURE 14. Walkeria prorepens Kubanin, 1992, Seongsan port, Jeju Island (MBRBK1705). A. Serpulid polychaete tube encrusted on inner side by small Walkeria colony. B. Close-up of small part of A, showing cluster of zooids. C. Live colony around in hole in substratum, showing a single expanded tentacle crown with eight tentacles. D. Two campylonemidan tentacle crowns of zooids inside hole. E. Part of colony viewed from above to show stolon, kenozooids and zooids. Scale bar: E = 0.20 m.