Conescharellina ocellata, Bock & Cook, 2004

Bock, Philip E. & Cook, Patricia L., 2004, A review of Australian Conescharellinidae (Bryozoa: Cheilostomata), Memoirs of Museum Victoria 61 (2), pp. 135-182 : 159-160

Conescharellina ocellata sp. nov.

Figures 13A–D

Holotype. NMV P311805 ; Miocene, Balcombe Bay , Victoria (see appendix).

Paratype. NMV P311806 ; Balcombe Bay , Victoria .

Other specimens. Victoria, Balcombe Bay (55 colonies); Batesford Quarry (see appendix) (45 colonies).

Etymology. ocellata (L.) – having little eyes, with reference to the appearance of the antapical peristomial avicularia.

Diagnosis. Conescharellina with minute, slightly domed colonies. Zooid orifices radial. Avicularia small, paired, lateral, with a minute ligula. Paired avicularia visible on the antapical side of the marginal peristomes.

Description. Colonies very small, domed, orifices appearing to be in radial series. Primary orifice with a short, narrow sinus and distinct paired condyles, with a laterally and antapically raised peristome. Adapical pore on the edge of the peristome. Avicularia small, rounded, paired and antapical, lateral to the sinus, bar with a minute ligula, orientated laterally and adapically. Adapical region with a few rounded pores, inferred to be root pores, with 2–3 small adjacent avicularia. Antapical region with a few avicularia and central cancelli; and with prominent, paired avicularia present on the antapical side of the peristome of marginal zooids.

Diameter of colony 2.4 mm, height 1.6 mm, up to 6 radial whorls, 5–7 zooids per whorl.

Remarks. C. ocellata is easily recognisable in unworn colonies by the paired antapical avicularia on the marginal peristomes. C. ocellata resembles C. eburnea and Trochosodon diammotos in this character but differs in all its dimensions and in the shape of the primary orifice. It differs from C. macgillivrayi in its domed colonies, radially arranged orifices, shape of the primary orifice, and rarity of antapical cancelli. It differes from C. humerus in the position and shape of the primary orifice and position of the lateral avicularia, especially in antapical view.

Figures

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.