Arbopercula Nikulina 2010

Genus Arbopercula Nikulina, 2010 Amended diagnosis

Colony encrusting, multiserial, unilaminar or multilaminar. Zooids elongated, oval, in serial rows separated by deep groves. Gymnocyst reduced or slightly extended proximally. Mural rim narrow, surrounding an elliptical opesia. Cryptocyst granular, reduced, more developed proximally. Operculum well chitinized. Marginal spines present, but sometimes lacking in large parts of the colony or in the whole colony; sometimes bending across the opesium like a shield, but not fusing. Oral spines absent. A pair of processes, conical or spine-like, developed in the proximal gymnocyst of each zooid, inconstant; a single process in the first zooid of a row after bifurcation. Communication via two multiporous rosette-plates, each situated in one of the basal corners of the distal wall. Distal half of each lateral wall with a single multiporous rosette-plate. Small, irregular kenozooids may be present, filling spaces between autozooids. Ovicell and avicularia absent. Ancestrula and early budding pattern undescribed.