Trochosodon ampulla ( 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 : 165-166

Trochosodon ampulla ( Maplestone, 1909)

Figures 16A–C

Bipora ampulla Maplestone, 1909: 269 , pl. 76 figs 4a, b, 5a, b.

Conescharellina ampulla . — Livingstone, 1924: 212.

Trochosodon ampulla . — Canu and Bassler, 1929: 493.— Harmer, 1957: 744.

Specimens examined. BMNH 2000.2 .23.1 (part of material sent by Maplestone to the Natural History Museum, 1 colony) . NMV F99005 , F99006 , labelled by Maplestone, almost certainly part of the type material from NSW; and NMV F101968 , same collection (6 additional colonies) .

Description. Colony forming a very low dome, distinctly wider than high. Orifices quincuncially arranged, rapidly obscured by extrazooidal and kenozooidal calcification. Prominent, flask shaped, marginal zooids with elongated, tubular peristomes. Primary orifice slightly elongated, with a small pointed sinus. Adapical pore present outside peristome. A few scattered pores (root pores?) present adapically. Avicularia small, often paired, placed laterally and adapically beside each peristome, rostrum almost semicircular, bar with a minute ligula. Antapical surface with a small central region of cancelli.

Colonies up to 4.7 mm in diameter and 1.6 mm in height; with approximately 8 whorls, each with 10 zooids.

Remarks. The specimens examined are somewhat worn and show few primary orifices, deeply hidden by the elongated peristome. The peristomes of the marginal zooids are tubular and prominent, the calcification is thickened and there are only one or two apparent adapical pores. Antapical cancelli are usually confined to a small, central area, although a much larger area was figured by Maplestone (1909). The species is distinguished by large size and stellate colony form with very prominent tubular marginal peristomes.

Specimens additional to the types suites of T. ampulla have not been reported since its first description. This, taken together with Maplestone’s labelling of the NMV specimens and the occurrence in this collection of other, apparently unique records from New South Wales, of Zeuglopora lanceolata etc., strongly suggests that these specimens are part of the original type suite.

Figures

Figure 16. Trochosodon ampulla (Maplestone, 1909). A, NMV F99005, adapical view of colony, scale = 1 mm. B–C, NMV F99006. B, lateral view of larger colony, scale = 1 mm. C, detail of orifice and avicularia, scale = 100 µm.