Bipora flabellaris Levinsen, 1909

Bock, Philip E. & Cook, Patricia L., 2004, A review of Australian Conescharellinidae (Bryozoa: Cheilostomata), Memoirs of Museum Victoria 61 (2), pp. 135-182 : 163

Bipora flabellaris Levinsen, 1909

Figures 15A–E

Bipora (?) elegans .— Whitelegge, 1887 (not d’Orbigny, 1852). Flabellopora elegans . — Waters, 1887: 200.

Flabellipora flabellaris Levinsen, 1909 .— Livingstone, 1924: 211.

Specimens examined. NMV F99003, stn GAB-020 (2 colonies); NMV F101966, stn GAB-030 (2 colonies); NMV F99004, stn GAB-116 (1 colony); NMV F101967, stn GAB-118 (1 colony).

Description. Colony fan-shaped, composed of 2 apposed zooidal faces, separated by an intervening cancellated and avicularian layer. Adapical region often extrazooidally thickened, with rhizoids arising from small lunate pores. Zooid primary orifice with a subtriangular sinus and paired condyles. Adapical pore present outside peristome. Peristome raised laterally. Avicularia paired, lateral and antapical, rostrum rounded, directed adapically, bar without ligula.

Colonies up to 10 mm wide, 8 mm deep.

Remarks. Many of the specimens examined here are worn. Only one, from stn GAB-020, has three long roots (width 0.25 mm, length 2.0 mm), that arise from the adapical region of a large colony from 155 m depth.

B. flabellaris is obviously very closely related to species of Conescharellina . The early growth stages are hardly distinguishable, except for the slight flattening of the colony. Later stages, however, emphasise the cancellated region, that curves round the antapical edge and protrudes beyond the orifices of the zooidal series of each face, producing the typical fan-shaped colony. All the specimens examined here appear to belong to one species but it is possible that other forms of Bipora may eventually be found from the Australian region.

Figures

Figure 15. Bipora flabellaris (Levinsen, 1909). A–D, NMV F99003. A, young colony, direction of growth arrowed, scale =100 µm. B, antapical view of colony, showing narrow kenozooidal region (arrowed), scale = 1 mm. C, detail of orifices with adapical pores, and avicularia, scale = 200 µm. D, adapical region, showing lunate root pores, scale = 200 µm. E, NMV F99004, large worn colony at late growth stage, showing flabelliform shape and everted antapical region, direction of growth arrowed, scale = 2 mm.