Bathycyclopora vibraculata ( Calvet, 1931 ) Berning & Harmelin & Bader & Cibio, 2017

Berning, Björn, Harmelin, Jean-Georges & Bader, Beate, 2017, New Cheilostomata (Bryozoa) from NE Atlantic seamounts, islands, and the continental slope: evidence for deep-sea endemism, European Journal of Taxonomy 347, pp. 1-51 : 32-34

Bathycyclopora vibraculata ( Calvet, 1931) gen. et comb. nov.

Fig. 11 A–F, Table 11

? Phylactella vibraculata Calvet, 1931: 113 , pl. 2, figs 17–18.

Material examined

Lectotype (here designated)

AZORES: 2 ovicellate colonies on a coral fragment, the larger one with an ancestrula is the lectotype ( MOM INV-22480 a), the smaller one a paralectotype ( MOM INV-22480 b), dry, Stn 2.

Paralectotypes

AZORES: 1 colony on coral fragment, dry, Stn 2 ( MOM INV- 22679); 1 colony on coral fragment, dry, Stn 2 ( MOM INV- 22680); 1 colony fragment, dry, on slide, severely affected by Bynesian decay, Stn 2 ( MOM INV- 22479).

Description

Colony encrusting, unilaminar, multiserial, forming small patches ( Fig. 11A ). Zooids relatively large, hexagonal or polygonal, separated by grooves ( Fig. 11 B–C); lateral walls well developed, becoming more extensive distally, gently sloping, with a single basal pore chamber connecting each neighbouring zooid ( Fig. 11C ), round septular pore surrounded by a large area of cryptocyst with a surface similar to that of frontal shield, framed by a narrow and slightly raised ridge of gymnocystal calcification, separated from neighbouring pore chamber by a suture, pore in distal pore chamber slightly raised with respect to lateral ones. Frontal shield convex, imperforate except for a single row of numerous conspicuous marginal pores, gently rising distally towards a suboral crest with a blunt or occasionally triangular central umbo that is laterally sloping towards proximal pair of spines ( Fig. 11D ); surface rugose and with irregular wrinkles, superimposed by fine granules.

Orifice about as wide as long, distal half rounded and with a conspicuous immersed shelf along entire distal margin, lateral margins parallel, proximal edge slightly concave; condyles conspicuous, rectangular or roughly triangular, distinctly set off from orifice margins ( Fig. 11F ); distolateral orifice margin with seven or rarely six evenly spaced spines, six spines with a distinct distal gap in potentially maternal zooids.

Ovicell hyperstomial, ooecium resting on or slightly immersed in distal zooid’s frontal shield ( Fig. 11D ), globular, in general wider than long, with a very short tubular peristome wedged in between distalmost pair of spines and terminating at distal orifice margin; smooth ectooecium a narrow band around base of ooecium, broadening proximally to frame ooecial aperture ( Fig. 11E ); exposed endooecium imperforate, surface topography similar to that of frontal shield; ooecial aperture suborbicular, not closed by operculum.

Adventitious avicularia paired, small, oval, lateral to orifice near distolateral zooidal corners ( Fig. 11 D– E); rostrum short, semicircular to semielliptical, slightly raised distally, directing laterally or distolaterally, palate an immersed distolateral shelf framing a suborbicular opesia; crossbar incomplete, composed of two short inwardly curved triangular condyles, proximal uncalcified area reduced, semicircular. Interzooidal avicularia frequent in late astogenetic parts of colony, emplaced on a polygonal cystid with variably developed cryptocyst-type granular frontal shield and a row of marginal pores as in autozooids ( Fig. 11 C–D); rostrum slightly to distinctly spatulate, slightly raised distally, of variable size and pointing in various directions, most of palate occupied by a broad flat shelf with a V-shaped proximal edge caused by indentation of distal uncalcified area; crossbar broad laterally and much thinner towards centre when complete, or reduced to a pair of short triangular condyles; proximal uncalcified area reduced, semicircular.

Ancestrula tatiform, oval (ca 500 µm long, 350 µm wide), smooth gymnocyst presumably narrow all around, cryptocyst absent; opesia large (ca 380 µm long, 260 µm wide), oval, slightly constricted in distal fifth; 11 spines, with five proximal ones widely spaced and six distal ones situated closer together ( Fig. 11B ).

Remarks

As Calvet (1931) did not explicitly mention a holotype, we here designate as lectotype the specimen that was presumably depicted on pl. 2, figs 17–18. The species epithet stems from a misinterpretation of the small adventitious avicularia, which Calvet (1931: 114) thought were vibracula. The mandible is, however, confined to the rostrum, moves in one plane only, and is therefore a normal avicularium ( Fig. 11E ). Bathycyclopora vibraculata gen. et comb. nov. has never been reported again after its discovery.

Ecology

All available colonies encrust dead coral skeletons at ca 600 m depth, forming small patches.

Distribution

Bathycyclopora vibraculata gen. et comb. nov. was found at a single station off NW Terceira Island (Azores).

Figures

Fig. 11. Bathycyclopora vibraculata (Calvet, 1931) gen. et comb. nov., Azores. A. Overview of lectotype (MOM INV-22480a). B. Periancestrular region (MOM INV-22480a). C. Zooids at the colony growth margin and interzooidal avicularia (paralectotype, MOM INV-22480b). D. An ovicellate zooid and an interzooidal avcularium (paralectotype, MOM INV-22480b). E. Lateral view of an ooecium showing the thin marginal band of ectooecium (MOM INV-22480a). F. Close-up of orifice (MOM INV-22480a). Scale bars: A = 1 mm; B = 300 µm; C = 500 µm; D = 200 µm; E = 100 µm; F = 50 µm.