You are here
Bryozoa
Woodipora holostoma (Wood, 1844)
Nomenclature
-
Family: OnychocellidaeGenus: Woodipora
- holotype: B.M.(N.H.) Palaeont. Dept. B1639
SUMMARY
Colonies are multiserial, forming encrusting sheets, up to 11 mm in diameter in the holotype which encrusts the concave interior of a bivalve shell. Early astogenetic stages are unknown (damaged in the holotype).
Autozooids are broad, about 0.6 mm long by 0.4 mm wide, ovoidal to rhomboidal in outline shape with convex distal and concave proximal edges. The frontal wall is an extensive, slightly depressed, granular cryptocyst containing a pair of oval opesiules with their long axes oriented approximately tangentially to the proximolateral corner of the adjacent opesia, A thick, raised, densely granular mural rim surrounds the cryptocyst. The opesia is ovoidal, slightly broader than long, the length approximately 0.18 mm, with a proximal edge more gently curved than the distolateral edges. Ovicells have not been observed.
Vicarious avicularia are developed at zooid row bifurcations, constituting one of the two daughter zooids. They are approximately the same length as an autozooid but significantly narrower, measuring about 0.3 mm in width. The cryptocyst is granular and contains small, comma-shaped marginal pits at the shoulders on either side of the rostrum, the latter having the form of a high rounded arch. The opesia is longitudinally elliptical, variably and slightly constricted at approximately mid-length a little below the level of the comma-shaped pits. Autozooids distal and lateral of an avicularium tend to be slightly torqued such that the axes of their opesia are oriented towards the avicularium.