Conescharellina eburnea ( 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 : 146

Conescharellina eburnea ( Maplestone, 1909)

Figures 1E–H

Bipora ( Conescharellina ?) eburnea Maplestone, 1909: 270 , pl. 72 figs 6a, b.

Conescharellina eburnea .— Livingstone, 1924: 212.

Specimens examined. BMNH 2000.2.23.3, New South Wales (2 colonies, part of material sent by Maplestone to the BMNH, labelled “cotypes”); NMV F101879, stn SLOPE-2 (3 colonies).

Description. Colonies discoid, wider than high; slightly raised centrally, marginal zooids prominent. Calcification finely mamillate. Orifices in quincunx, patent, wide, with a rounded sinus and distinct condyles. Peristome not raised, with a rounded adapical pore on its edge. Root pores round, with a circlet of 3–4 minute avicularia, tending to occur near the adapical region only. Other avicularia paired, small, rounded, closely distolateral to the adapical margin of the orifice, orientated distolaterally, with a minute ligula. At the proliferal margin, these avicularia appear on the antapical surface of the zooids and closely resemble the paired avicularia of C. ocellata , C. perculta , and Trochosodon diommatus (see also Figs 11B , 13C , 21B ). There are only a few cancelli on the solid antapical surface but a regularly distributed series of small, rounded avicularia.

Colony diameter 4–5 mm, height 1 mm, number of whorls 8, number of zooids per whorl 10.

Remarks. Maplestone’s specimens were from 22 miles east of Port Jackson, from 146 m; he did not give details of the number of colonies. There are few records of this species, all from New South Wales. The distinctive features are the patent orifices, that possess hardly any peristomial rim, the rounded sinus, and the paired, antapical peristomial avicularia. The circular root pores, each surrounded by small avicularia, resemble those of several other species of Conescharellina (see C. plana sp. nov., C. ocellata sp. nov.) and of Crucescharellina australis sp. nov.

Figures

Figure 1. A–D, Conescharellina sp. A–C, NMV F98977, colony; direction of growth arrowed; scale=1 mm, B, detail of orifices and avicularia, scale = 500 µm, C, detail of orifice with adapical pore (arrow), scale=100 µm. D, NMV F98978, colony from antapical surface with commensal coral, scale = 1 mm. E–H, Conescharellina eburnea (Maplestone, 1909). E, BMNH 2000.2.3.33, adapical view of colony, scale=1 mm. F–H, NMV F98979. F, adapical view of colony showing root pores, scale = 500 µm. G, antapical view of colony with small, central and paired marginal peristomial avicularia (arrow), scale=500 µm. H, detail of orifices and avicularia, adapical pore arrowed, scale= 100µm.

Figure 11. Conescharellina perculta sp. nov. A, NMV F98998, holotype. A, adapical view of colony, scale = 200 µm. B, NMV P98999, antapical view of marginal peristomes, scale = 200 µm. C–D, NMV F98998, holotype. C, detail of orifices, peristomes, and avicularia, scale = 200 µm. D, detail of root pore, scale = 200 µm.

Figure 13. A–D, Conescharellina ocellata sp. nov. A–B, NMV P311805. A, adapical view of colony, scale = 500 µm. B, detail of orifices, avicularia and septular pores, scale = 200 µm. C–D, NMV P311806. C, antapical view, scale = 500 µm. D, marginal view showing peristomes and paired avicularia (arrow), scale = 200 µm. E–F, Conescharellina macgillivrayi sp. nov. NMV P311810. E, adapical view of colony, scale = 500 µm. F, detail of orifices with adapical pores, peristomes and avicularia, scale = 200 µm.

Figure 21. Trochosodon diommatus sp. nov. A. NMV F99012, holotype. Detail of orifices and adapical pores, scale = 200 µm. B, NMV F99013, paratype, antapical view of marginal peristomes, showing paired avicularia, scale =200 µm. C. NMV F99014, paratype, detail of peristome, orifice, and lunate root pores, scale = 200 µm.