Cinclidia aculeata Denisenko 2018, n. sp.

Cinclidia aculeata n. sp.

(Fig. 2; Table 1)

Material examined. Holotype: ZMUC-BRY-115, one colony on rock, Stn 604, 61°35’34’’ N, 5°05’36’’ W, 260 m, 12 April 1990, collected by heavy triangular dredge. BIOFAR program, RV Magnus Heinason, Faroese Fishery Investigations.

Distribution. East and south off the Faroe Islands archipelago, slope and outer part of the shelf.

Etymology. Latin aculeata, spiny.

Description. Colony small, irregular in outline, multiserial, unilaminar, white when non-bleached. AutoZooids mostly oval, slightly convex, with distinct boundaries marked by deep grooves and, sometimes, interZooidal kenoZooids (Fig. 2a‒c). Intramural reparative budding fairly common. Lateral gymnocyst narrow; proximal gymnocyst more extensive, often forming narrow extension(s) between proximolateral neighboring Zooids. Frontal spinocystal shield thin, flat, with narrow radiating costae (10‒14 pairs), lacking bifurcations. Costae separated by 4‒6 oval or round intercostal foramina, decreasing in siZe towards shield centre (Fig. 2b). Each costa bearing 2‒3 short tubular spines, each with a tiny apical pore (pelmatidium), their height decreasing towards midline of shield. In older part of colony, costae becoming wider and thicker, with intercostal foramina smaller and pelmatidia less visible or occluded (Fig. 2d). Orifice broader than long, transversely D-shaped, bounded distally and laterally by thin, low peristome terminating as small condyles visible beneath operculum; proximal edge of orifice formed by thickened peristomial (apertural) bar formed by more robust, thicker distalmost costal pair; bar with four (two on each costa) short spines with pelmatidia (Fig. 2c‒d). Four articulated oral spines distal and lateral to peristome; distalmost pair thinner than lateral pair. Spine tips initially simple, becoming bifurcate (Fig. 2c‒d); only lateral bifurcate spine visible in ovicellate Zooids. InterZooidal kenoZooids present (Fig. 2c). No avicularia. Ovicells terminal, prominent, cleithral (Fig. 2c, f). Ooecium produced by distal kenoZooid; globular, slightly wider than long. Smooth ectooecium partially calcified, with transverse membranous area (window) (Fig. 2c, f). In cleaned specimens, area of endooecium beneath window bearing numerous pseudopores. Ooecial proximal margin with triangular or irregular lip (Fig. 2b, e). Communication between Zooids via basal pore chambers. Ancestrula absent.

Remarks. Ontogenetic changes in costal shape appear to result from secondary calcification subsequent to intramural budding of autoZooids.

N, number of measurements; SD, standard deviation.

FIGURE 2. Cinclidia aculeata n. gen. et sp. holotype ZMUC-BRY-115. a–b, group of ovicellate and non-ovicellate autozooids; c, autozooid with intramural budding, kenozooid in the centre, ooecium and bifurcated oral spine on the right; d, layered costae and morphology of ooecia in the old part of the colony; e, frontal shield showing apertural bar, pelmatidia and bifurcate oral spines in the old part of the colony; f, colony periphery showing ooecium and basal pore chambers.