Thalamoporella neogenica Buge, 1951
Colonies are multiserial, forming extensive encrusting sheets. Early astogenetic stages are not preserved in the few specimens known from the Coralline Crag.
Autozooids are about 0.41-0.43 mm long by 0.25-0.30 mm wide, typically rectangular in outline shape, with a concave proximal edge and a convex distal edge. The frontal wall is an extensive, slightly depressed cryptocyst containing a single pair of opesiules roughly mid-length, and is raised around the edges of the zooid. The cryptocyst was probably originally granular but in specimens from the Coralline Crag its texture is masked by epitaxial cement overgrowths which may also occlude the opesiules. The opesia is small, about 0.07 mm long by 0.11 mm wide, and hemielliptical with a straight proximal edge. Ovicells have not been observed.
Vicarious avicularia occur at zooid row bifurcations or occasionally replacing autozooids in-between bifurcations. They are approximately the same length as an autozooid and have a proximal cryptocyst containing two pairs of elongate opesiules, the more proximal pair closer to the midline of the zooid. The opesia is small and trifoliate. An extensive rounded rostrum is present, in some instances partly overarched by a hood of gymnocystal calcification superficially resembling an ovicell.
The characteristic vicarious avicularia enable this species, which is rare in the Coralline Crag, to be distinguished from similar encrusting anascan cheilostomes with extensive cryptocystal frontal walls. None of these other species (e.g. Manzonella fissurata, Woodipora holostoma) have avicularia with two pairs of opesiules and a small trifoliate opesia.
Whether or not this species actually belongs to Thalamoporellidae has yet to be resolved. The avicularia do not match closely with those seen in other thalamoporellids and the diagnostic spicules and bivalved ovicells have not been observed. In some respects, T. neogenica is more reminiscent of the microporid Calpensia, although this genus normally lacks avicularia.
Pliocene, Late Zanclean–Early Piacenzian, Coralline Crag Formation, Suffolk, UK.
Buge (1957) noted this species from various Pliocene and Miocene localities in France, Egypt and Italy. These records require re-evaluation.