Cellaria spatulifera n. sp.

(Fig. 7)

Cellaria sp. 10: Achilleos et al. 2019: [4–7].

Material examined. Holotype: NIWA 128669, cruise TAN0413, Stn 109, 37.5488º S, 176.9878º E, Bay of Plenty, 136–142 m, collected 13 November 2004. Paratype: NIWA 128752, cruise TAN1105, Stn 43, 33.9875 º S, 171.7508 º E, Middlesex Bank, 170 m, 170–174 m, collected 28 March 2011.

Etymology. Latin spatula, small spoon or paddle, plus fero, bear, carry, alluding to the shape of the avicularian mandible.

Diagnosis. Colony branching laterally. Autozooids back to back in pairs, widening to whorls of three. Opesia wider than long with beaded distal rim and smooth convex proximal rim with knob-like condyles. Fully vicarious avicularia with spatulate rostrum and longitudinally oval foramen. Female zooids dimorphic, broader than autozooids, with semicircular ooecial opening.

Description. Colony erect, jointed, laterally branched; stem fragments not> 10 mm in length. Stem slender, cylindrical in widest parts, narrower proximally and between ovicellate sections (W, 91–422 μm). Zooids arranged back to back in alternating pairs proximally, later whorls comprising 3 zooids; up to 16 whorls along a stem.

Zooids unequally hexagonal in outline, longer than wide (ZL, 350–471 μm; ZW, 220–310 μm; ratio 1.43). Cryptocyst mostly smooth with sparse granulation except for opesial and proximal areas bounded by cryptocyst ridges; these ridges continuous proximally, almost merging with zooid margin distally. Opesia wider than long (OpL, 40–74 μm; OpW, 67–101 μm; ratio 0.7), its thin margin slightly raised, distally beaded, the strongly convex proximal rim flanked by upturned knob-like condyles.

Avicularia fully vicarious; cystid more or less elongate-hexagonal but the distal third narrowest. Rostrum half the length of cystid; directed distally and slightly curved, spatulate overall, with triangular proximal third that broadens to spoon-shaped part which occupies full width of cystid distally. Palate smooth except for elongate hourglassshaped area with granulation distally, tuberculation proximally. Rostral foramen longitudinally oval. Mandibular pivots horizontal, their inner ends converging proximolaterally, not fusing but leaving thin suture. Avicularian opesia with widely narrow crescentic slit with granular proximal margin; cryptocyst inversely triangular, with sparse granulation. Edge of cryptocyst defined by smooth continuous ridges (AvCL, 402–449 μm; AvCW, 200–227 μm; ATL, 245–253 μm; ATW, 104–119 μm; RL, 233–236 μm; RW, 104–119 μm).

Female zooids dimorphic, being broader than autozooids with wider opesiae. Ovicells with granular frontal face sloping downwards proximally to level below opesial rim; ooecial opening almost semicircular, with corners extended transversely as short slits (OvApL, 11–30 μm; OvApW, 30–84 μm; ratio 0.3).

Ancestrula not definitely seen. Proximal-most zooids with frontal rootlet pores.

Remarks. The avicularium of Cellaria spatulifera n. sp. is strikingly unique among the species in this genus. Overall, C. spatulifera n. sp. most resembles C. stenorhyncha n. sp. In fact, in the absence of avicularia the two species are easily confused, autozooids being more or less identical.

Distribution. Endemic; Bay of Plenty, New Zealand, 136–142 m depth.