Walkeria prorepens Kubanin 1992

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.