Conescharellina macgillivrayi, 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 : 160-161

Conescharellina macgillivrayi sp. nov.

Figs 13 E-F, 14A

Bipora philippinensis . — MacGillivray, 1895: 89, pl. 12 fig. 2.

Holotype. NMV P311810 , Miocene, Balcombe Bay , Victoria.

Paratypes. NMV P311811 , Balcombe Bay .

Other specimens, Miocene, Balcombe Bay (approximately 209 colonies); Miocene, Bairnsdale (12 colonies); Miocene, Batesford Quarry (22 colonies); Miocene, Heywood Bore (approximately 63 worn colonies); Miocene, Muddy Creek (13 colonies), Miocene, Puebla Clay, Torquay (16 colonies); Miocene, Mount Schanck, South Australia (approximately 100 colonies).

Etymology. Named for P.H. MacGillivray.

Diagnosis. Conescharellina with fairly flat, small colonies. Zooid orifices arranged quincuncially, marginal peristomes prominent. Avicularia rare. Root pores circular. Antapical surface with cancelli.

Description. Colonies fairly flat, distinctly wider than high, peristomes prominent marginally. Calcification finely tuberculate. Zooid orifices obviously quincuncial, sinus short and rounded, with paired condyles. Peristomes raised laterally and antapically; adapical pore outside the peristome. Root pores round, small, adapical. Avicularia rare, lateral or antapical, rounded, bar with a minute ligula. Antapical surface with large cancelli and minute avicularia.

Colony diameter 1.9 mm, height 1.25 mm, number of whorls 6, zooids per whorl 8.

Remarks. Colonies of C. macgillivrayi are the most numerous of the fossils found in the Victorian and South Australian Tertiary samples, although many colonies are worn and their identity has had to be inferred from their proportions and orifice pattern. Comparison of the colonies with MacGillivray’s (1895) specimen of “ Bipora philippinensis ” ( NMV P 27728) indicates that they are conspecific and it is also possible that this species is the “ Lunulites cancellatus ” of Waters (1882b: 512, pl. 22 figs 10, 11) from Bairnsdale, although this was figured with more numerous avicularia. None of his specimens has been examined.

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.