Setosella Hincks, 1877

Rosso, A., Martino, E. Di & Gerovasileiou, V., 2020, Revision of the genus Setosella (Bryozoa: Cheilostomata) with description of new species from deep-waters and submarine caves of the Mediterranean Sea, Zootaxa 4728 (4), pp. 401-442 : 403

Genus Setosella Hincks, 1877

Type species. Membranipora vulnerata Busk, 1860

Amended diagnosis. Colony small, either encrusting, unilaminar, with autozooids arranged in single, double or multiple spirals (more apparent in some species/colonies) or quincuncially; or free-living either scorpioid or ringshaped. Autozooids usually rhomboidal, with a variably exposed gymnocyst and an ovoidal frontal area outlined by a mural rim. Cryptocyst often granular, depressed and relatively flat, pierced by two-to-five paired, slit-like to roundish opesiules. Slit-like opesiules asymmetrical, the left one usually the wider. Opesia distal, transversely D-shaped, dimorfic in ovicellate zooids, with a distal tuberculate shelf. Spines absent. Communication through uniporous septula. Interzooidal vibracula globular, placed disto-laterally to each autozooid, rarely distally, with a long seta; opesia eight-shaped, constricted by two blunt, asymmetrical condyles. Ovicell produced by the maternal autozooid, terminal, cleithral, immersed or subimmersed, with crescent-shaped kenozooidal ooecium; ectooecium gymnocystal, smooth, with a central pseudopore or a subcircular, variable in size (membranous when non-cleaned) window often exposing the endooecial surface. Ancestrula oval, smaller than autozooids, usually with a smooth cryptocyst demarcating an ovoidal, to semielliptical or trifoliate opesia; budding 1–2 sessile or caudate vibracula, sometimes with the interposition of a kenozooid. Interzooidal kenozooids roughly similar in size and shape to autozooids, but with a small, variably shaped, centrally placed opesia, rarely occur.

Remarks. The emendation of the genus Setosella is required to include colonies arranged in tightly coiled spirals ( S. spiralis ) as well as free-living (the already established S. folini and the newly erected S. alfioi n. sp.), in addition to the occurrence, although rarely, of kenozooids with different morphologies ( S. cavernicola and S. cyclopensis n. sp.).