Turbicellepora faroensis, Denisenko, 2018

Denisenko, Nina V., 2018, New Cheilostomata (Bryozoa) species from sublittoral and bathyal zones off the Faroe Islands, with some comments on allied taxa, Zootaxa 4375 (1), pp. 116-126 : 120-122

Turbicellepora faroensis n. sp.

(Fig. 3; Table 2)

Etymology. Alluding to the Faroe Islands where the species was first found.

Material examined. Holotype: ZMUC-BRY-116, colony fragment on a polychaete tube, Stn 89, 60°31’6’’ N, 6°47’ W, 396 m, 22 July 1987, collected by detritus sledge. BIOFAR program, RV Magnus Heinason, Faroese Fishery Investigations. Paratype: ZIN ‒ 1/50660, part of colony, Stn 470, 62°39’06’’ N, 5°42’72’’ W, 335 m, 22 July 1987, collected by heavy triangular dredge. BIOFAR program, RV Magnus Heinason, Faroese Fishery Investigations.

Distribution. Colonies were found to the north and southeast of the Faroe Islands at the boundary of Boreal and Arctic water masses ( Hansen & Østerhus 2000).

Description. Colonies initially laminar, encrusting, later lumpy, forming patches 20 mm x 10 mm in siZe, white-cream if unbleached, encrusting polychaete tubes. In laminar part, autoZooids flattened in horiZontal plane, in lumpy part appearing slightly convex and semi-erect (Fig. 3a‒c). AutoZooids varying in shape, usually square or rectangular, separated by distinct sutures. Frontal shield thick, smooth, with sparse marginal areolar pores (Fig. 3b‒ c). Primary orifice suboval, wider than long, normally with wide, shallow U-shaped sinus (Fig. 3b‒d, f), occupying approximately half proximal border (Fig. 3d, f) and surrounded by a relatively high, flared peristome. A single suboral avicularium in non-ovicellate Zooids, very prominent, with columnar cystid fused to peristome; apical part inclined to orifice and directed laterally, with rostrum and mandible clearly visible (Fig. 3d‒e); base of cystid rather narrow, curved, bean-shaped or oval in cross-section; distal part of cystid forming a tall, spine-like umbo (often appearing broken). Mandible triangular, rostrum hooked; crossbar complete, lacking columella. Suboral avicularium originating from marginal areola; an additional communication pore sometimes present (Fig. 3f). Owing to its extreme convexity, cystid of suboral avicularium remaining visible between Zooids of new layer (Fig. 3b‒c). Paired (sometimes single) distolateral avicularia present in ovicellate Zooids, apparently originating from two lateral perioral areolae and appressed to ooecium on both sides. These avicularia with long, tubular curved cystid surrounding ovicell opening, and associated with distal part of the peristome; rostrum slightly hooked, mandible oval, with complete crossbar, lacking columella (Fig. 3b‒c, g). Both suboral and distolateral avicularia with pore cystid base (Fig. 3b‒c, g), connecting avicularian cystid with hypostegal coelom of autoZooid. InterZooidal avicularia frequent, large, prominent, spatulate, with wide and strongly concave palate, crossbar lacking columella (Fig. 3h). Avicularian frontal surface seen in lateral view. Ovicell hyperstomial, non-cleithral, with smooth globular ooecium that slightly varies in shape, being sometimes wider than long, with 15‒20 large pseudopores of variable shape, irregularly spaced (Fig. 3b‒c). Ancestrula not found.

Remarks. The appearance of the orificial sinus can vary, usually it is wide and U-shaped but in some intramurally budded Zooids it can appear narrow and V-shaped (Fig. 1e). The new species resembles Turbicellepora hansenae Denisenko, 2016 (see description below and Fig. 4), in having distolateral avicularia in fertile Zooids, which originate from lateral perioral areolar pores. Both species also have similar Zooid siZe. These species differ in the shape of the sinus of the primary orifice, being shallower and wider in T. faroensis n. sp. (Fig. 3d, f) than in T. hansenae (Fig. 4d). A difference is also observed in the siZe and shape of cystids of suboral avicularia. The latter are larger and less prominent in T. hansenae (Fig. 4b‒c) in comparison to T. faroensis n. sp. The base of the suboral avicularian cystid in T. faroensis n. sp. is narrow and curved, in contrast to the wide avicularium base in T. hansenae , which extends practically to the middle of the frontal shield. Further, the apical part of the suboral avicularian cystid is sharply umbonated in T. faroensis n. sp., whereas it is blunt in T. hansenae . The shape of the distolateral avicularia of the new species resembles that in T. hansenae but the rostrum is less hooked in this species. There are also differences in the morphology of the peristome, which is more protruding in T. faroensis n. sp. Ooecial shape is similar in both species but the ooecial medial ‘fold’ was not observed in T. faroensis n. sp.

FIGURE 3. Turbicellepora faroensis n. sp. holotype ZMUC-BRY-116. a, part of the colony; b, group of zooids with a spinelike, broken, suboral avicularium (unbleached colony); c, group of zooids with two different types of adventitious avicularia enclosed in the peristome; d, autozooid showing primary orifice and base of suboral avicularium; e–f, two examples of variability of the orificial sinus; g, shapes of the rostrum of suboral and distolateral avicularia; h, interzooidal avicularium.

N, number of measurements; SD, standard deviation.