Conescharellina magniarmata ( Maplestone, 1909 )

Bock, Philip E. & Cook, Patricia L., 2004, A review of Australian Conescharellinidae (Bryozoa: Cheilostomata), Memoirs of Museum Victoria 61 (2), pp. 135-182 : 148-149

Conescharellina magniarmata ( Maplestone, 1909)

Figures 3A, B

Bipora magniarmata Maplestone, 1909: 269 , pl. 75 figs 3a, b. Conescharellina magniarmata .— Harmer, 1957: 729.

Specimens examined. BMNH 2000.2.23.5 (2 colonies, part of material sent by Maplestone to the BMNH, labelled “cotypes”); NMV F98984 (12 colonies, labelled in Maplestone’s hand, inferred to be from NSW); NMV F101891, South Australia (1 colony, Maplestone’s specimens, no other information); NMV F101892, stn BSS- 167 (4 colonies with roots and antapical corals); NMV F101893, stn BSS- 170 (2 colonies with antapical corals); NMV F101894, stn BSS- 171 (1 colony); NMV F101895, stn GAB- 015 (1 colony); NMV F101896, stn GAB- 020 (1 colony); NMV F101897, stn GAB- 056 (1 colony).

Description. Colony conical, becoming large, broader than previous species, with adapical extrazooidal, kenozooidal and avicularian growth forming a prominent “lump” quite early in astogeny. Orifices in 6–8 radial series, slightly elongate, with an extended sinus; secondary orifices with laterally raised peristomes, forming “costules”. Adapical pore outside the peristome. Avicularia very large, originating beside the orifice, acute, orientated distolaterally, with a wide, curved, palatal flange surrounding an opesia, and a bar with at least 3 large ligulae. Lunate root pores present, each with a pair of small lateral avicularia. Mature colonies with solid antapical extrazooidal calcification and avicularia.

Height of colonies 3.0 mm, diameter 3.0 mm, number of zooid whorls 8–9, number of zooids per whorl 8.

Remarks. Livingstone (1924) regarded C. magniarmata as a synonym of his “ C. angulopora ” but Harmer (1957) was doubtful of the identity of the two forms. The avicularia certainly distinguish C. magniarmata . Few of the colonies assigned here to C. cognata show any intermediate characters, although the two forms are obviously very closely related. All the specimens from eastern Australia have elongated conical colonies but one from south-western Australia (stn GAB- 015) is very small and domed. However, it has typical “ magniarmata ”- type avicularia, with a wide palatal flange and is therefore referred to this species.

Figures

Fig.3. A–B, C. magniarmata Maplestone, NMV F98984. A, Lateral view of colony, growth direction arrowed, note adapical secondary calcification, scale= 1 mm. B, detail of orifice with adapical pore and avicularium, scale= 100 µm. C–G, Conescharellina cognata sp. nov. C–E. NMV F98985, holotype. C, lateral view of large colony, growth direction arrowed, scale = 2 mm. D, margin of proliferal region in antapical view, showing zooid orifices with adapical pores and “concealed” frontal shields with marginal septular pores. Chambers of alternating developing interzooidal avicularia arrowed, scale = 500 µm. E, detail of orifices with adapical pores, one with entooecial and ectooecial laminae of developing ovicell (arrow); large, interzooidal avicularia and lunate root pore with small paired avicularia, scale = 200 µm. F, NMV F98986, antapical view of small colony, showing central area of cancelli and alternating “concealed” zooids with marginal septular pores, scale = 500 µm. G. NMV F98985, holotype, detail of antapical surface of large colony, showing alternating series of cancelli, minute avicularia and extensions of septular pores, scale = 200 µm.