Trypostega papillata (Busk, 1859)

Colonies are encrusting, multiserial, sheet-like. The ancestrula and early astogeny have not been described.

Autozooids are elongate rhomboidal to almost diamond shaped in outline, small, about 0.4 mm long by 0.3 mm wide. The frontal shield is a convex gymnocyst, smooth, evenly covered by pores about 10 µm in diameter, and with two raised umbones side-by-side a little proximally of the orifice. The orifice is about 0.08 mm long and wide, keyhole-shaped (cleithridiate), with a hemielliptical anter that is wider than high and is separated from the broad V-shaped poster by indentations beneath which are short, rounded condyles. Oral spines are lacking but a crescent of about 6 small pores may be visible around the distal edge of the orifice. The ovicell is large, about 0.3 mm long by 0.25 mm wide, porous, the pores similar to those of the frontal shield and decreasing in size centripetally towards a prominent median umbo.

Avicularia are lacking but small polymorphs (‘zooeciules’) are present scattered among but in significantly fewer numbers than the autozooids. The orifice is tiny, longitudinally elongate, about 0.05 mm long by 0.03 mm wide, with an anter and a poster.