Hippothoa imperforata Liu in Liu, Yin & Ma, 2001

Min, Bum Sik, Seo, Ji Eun, Grischenko, Andrei V. & Gordon, Dennis P., 2017, Intertidal Bryozoa from Korea — new additions to the fauna and a new genus of Bitectiporidae (Cheilostomata) from Baengnyeong Island, Yellow Sea, Zootaxa 4226 (4), pp. 451-470 : 457

Hippothoa imperforata Liu in Liu, Yin & Ma, 2001

( Figs 8–11 )

Hippothoa imperforata Liu in Liu, Yin & Ma, 2001: 533 , 792, pl. 35, figs 4, 5 (cum syn.).

Material examined. MBRBKSP029—Dumujin, Baengnyeong Island. Other material: Woosuk University collection—Baengnyeong Island: Dumujin (7 colonies), on rocky substrata; Wan Island (1 colony), on a dead bivalve shell.

Description. Colony uniserial, ramifying, up to 25 mm in overall colony spread. Autozooids very elongated, comprising an elongate-oval dilatation and long filiform cauda that is stolon-like and of variable length, from 0.7 to 3 or more times dilatation length. Gymnocystal frontal shield smooth, convex but with no carina, often with fine longitudinal and transverse striae. Budding of daughter zooids generally more or less cruciform, with a pair of zooids budded laterally from narrow triangular pore-chambers, within the lateral walls, distal to the midpoint of the dilatation; budding also mid-distally. Orifice at highest point of zooid, anter high-arched, with a broad, deep, rounded V-shaped sinus one fifth of orifice length, a pair of short rounded condyles in the corners between anter and sinus.

Measurements. ZL 231–288, (260) µm; ZW, 128–156 (142) µm; OrL, 47–70 (59) µm; OrW, 42–54 (48) µm.

Remarks. Female zooids were seen but inadvertently lost during preparation for SEM; they were noted by light microscopy as having an imperforate apex. Ancestrulae were not encountered. Liu et al. (2001) noted the similarity of this species with cosmopolitan Hippothoa flagellum Manzoni, 1870 and concluded that previous records of H. flagellum in the region pertained to H. imperforata . He noted that, whereas the ancestrula of H. flagellum is kenozooidal, that in H. imperforata is tatiform. Further, H. flagellum has a narrower V-shaped sinus ( Morris 1980) and a single mid-distal communication pore ( Gordon 1984), whereas the sinus of H. imperforata is more rounded and there are two distal communication pores ( Liu et al. 2001).

Distribution. China: Southeast of Hainan to the East China Sea southwest of Kyushu, Japan, 4– 139 m. Korea: Baengnyeong Island to south coast, 0– 80 m.

Figures

FIGURES 8 – 13. Hippothoa imperforata Liu in Liu, Yin & Ma, 2001, Dumujin. 8, Part of a ramifying runner-like colony showing three caudate autozooids; scale bar, 200 µm. 9, Autozooidal orifice; scale bar, 20 µm. 10, Frontolateral view of an autozooid, showing the elevated orificial rim; scale bar, 100 µm. 11, Autozooid viewed in transmitted light, showing the triangular pore-chambers in the lateral walls; scale bar, 100 µm. 12, 13, Celleporella hyalina (Linnaeus, 1767). 12, Young colony showing early astogeny (Namae port); scale bar, 500 µm. 13, Autozooidal (upper right), female (middle) and male (lower right) orifices (Jinchon-ri); scale bar, 100 µm.