Flabellopora d’Orbigny, 1851

Bock, Philip E. & Cook, Patricia L., 2004, A review of Australian Conescharellinidae (Bryozoa: Cheilostomata), Memoirs of Museum Victoria 61 (2), pp. 135-182 : 176

Flabellopora d’Orbigny, 1851

Flabellopora d’Orbigny, 1851: 52 . Flabillopora, d’Orbigny, 1852: 186 (bis) (lapsus).— Canu and

Bassler, 1929: 495.— Harmer, 1957: 749.— Silén, 1947: 47.— Lu,

1991: 72.

Type species. Flabellopora elegans d’Orbigny, 1851 (monotypy).

Description. Colony leaf-like or trilobed, superficially appearing to be bilaminar, anchored by root systems originating from lunate pores on the adapical edge. Zooids in alternating and interdigitating frontally budded series, orifices sinuate, the sinuses orientated antapically towards the growing edge. A small adapical pore sometimes present. Avicularia in patterns among orifices, usually small and rounded, with a bar but no ligula. Ovicells unknown but presumably originating from adapical pores.

Remarks. F. elegans was recorded by d’Orbigny (1851: 53) from about 20 m. “près de Ouantang et d’Hainan” in the China Sea. Later, d’Orbigny (1852: 186 bis) mentioned additional specimens from “dans le détroit de Malaca et à Manille” [sic]. Harmer (1957: 751) noted that Waters’ (1905: 9, pl. 1 fig. 5) figured specimen from the d’Orbigny collection was from Malacca. It was therefore certainly not of the type specimen and may not even have been of the same species. Waters’ figure, like those of Conescharellina from the d’Orbigny collection (see above), was semidiagrammatical and included only three zooid orifices. A photograph of the type specimen ( Taylor and Gordon, 2002, fig.3D) closely resembles d’Orbigny’s 1852 illustration but provides no details of the primary orifices or distribution of avicularia. As in the case of Conescharellina , the generic characters of d’Orbigny’s descriptions and illustrations are unmistakeable but the details of specific characters are obscure and require examination and redescription of the type specimen.

Delicate roots up to 25 mm in length were described by Harmer (1957), who noted their origin from lunate pores. In one of the trilobed colonies he illustrated, as F. irregularis (pl. 49 fig. 6), thirteen roots occur along the adapical edge of the colony. Ovicells are unknown in Flabellopora although d’Orbigny (1852: 186 bis) mentioned the presence of a “pore ovarien”. It is not known if this is the equivalent of the “proximal pore” of Harmer (1957) or the adapical pore, that is now known to be the origin of ovicells in Conescharellina and Trochosodon . Harmer (1957: 749, text-fig. 79) illustrated the central region of a colony expanse, that showed hemispherical areas of calcification adapically to zooid orifices. The surrounding calcification was raised into “lozenge-shaped” areas, a term used by Canu and Bassler (1929). Harmer suggested that each hemispherical calcification might represent the basal part (i.e. the ectooecium) of an ovicell. He figured and mentioned the presence of “proximal pores” but did not appear to associate them with ovicells. Adapical pores have been found frequently in the specimens examined here but they are usually associated with zooids that are marginal in position; they are not distributed in the centre of colony expanses, or surrounded by raised “lozenges”.