Cellaria stenorhyncha, Achilleos & Gordon & Smith, 2020

Achilleos, Katerina, Gordon, Dennis P. & Smith, Abigail M., 2020, Cellaria (Bryozoa, Cheilostomata) from the deep: new species from the southern Zealandian region, Zootaxa 4801 (2), pp. 201-236 : 213-216

Cellaria stenorhyncha n. sp.

( Fig. 8 )

Cellaria sp. 8: Achilleos et al. 2019: [4–7].

Material examined. Holotype: NIWA 23271 , cruise TAN0413, Stn 109, 37.5488º S, 176.9878º E, Bay of Plenty, 136–142 m, collected 13 November 2004. Paratypes: NIWA 12866 , cruise TAN1105, Stn 88, 36.1843º S, 173.6805º E, Northland west coast , 188–210 m, collected 1 April 2011; NIWA 23194 , cruise TAN0413, Stn 130, 37.35567º S, 177.0997º E, Bay of Plenty , 260–280 m, collected 14 November 2004.

Etymology. Latinised Greek, steno, narrow, and rhynchos, beak, alluding to the narrow avicularian rostrum.

Diagnosis. Colony branching dichotomously. Autozooids in whorls of 2–4. Opesia wider than long, lightly beaded distally with smooth convex proximal rim and knob-like condyles. Vicarious avicularia with narrowly elongate-triangular rostrum and rounded tip; narrowly crescentic opesial foramen. Female zooids dimorphic, broader than autozooids with narrowly crescentic ooecial opening.

Description. Colony erect, jointed, flexible, dichotomously branched; fragments not> 16 mm in length. Stem slender (W, 184–454 μm), tapering proximally, widest in the presence of ovicellate zooids. Zooids mostly arranged back to back in pairs (i.e. 2 zooids per whorl), with additional 1–2 zooids where stems widen; up to 10 or more whorls per stem.

Zooids more or less hexagonal in outline, rounded distally, longer than wide (ZL, 307–446 μm; ZW, 209–305 μm; ratio 1.4). Cryptocyst mostly smooth, moderately to sparsely granular only on inner flanks of cryptocystal ridg- es especially adjacent to opesia. Cryptocystal ridges continuous, forming smooth oval rim around sunken frontal area. Opesia wider than long (OpL, 46–61 μm; OpW, 70– 99 μm; ratio 0.65) the edge raised, lightly beaded distally and smooth proximally, the convex proximal rim flanked by upturned knob-like condyles.

Avicularia vicarious, rare, situated in distal third of internode. Cystid outline hexagonal overall but distal part shorter. Rostrum half-length of cystid, very narrowly triangular with rounded tip, sides weakly concave proximally, directed distally. Mandibular pivots with narrow attachment, each broadening and slightly splayed toward their point of near contact with weak suture between. Avicularian opesia more or less narrowly crescentic; subjacent cryptocyst a little more broadly crescentic, faintly granular (AvCL, 377 μm; AvCW, 66 μm; ATL, 231 μm; ATW, 66 μm; RL, 222 μm; RW, 66 μm; BL, 192 μm; BW, 61 μm).

Ovicellate zooids wider than autozooids, with slighter wider opesia. Ovicell with granular frontal face distal to opesia, with narrowly crescentic ooecial opening against distal rim of zooid. OvApL, 13–26 μm; OvApW, 90–109 μm; ratio 0.18.

Ancestrula not distinctly seen.

Remarks. The highly distinctive avicularia closely resemble those of Cellaria bassleri Hastings, 1946 in form (see Winston 2005), but both avicularian and autozooidal cystids in C. bassleri (a Gulf of Mexico–Caribbean species) are proportionally longer and narrower (fusiform) and ovicellate parts of internodes are not quite so broad. The avicularia of C. stenorhyncha n. sp. also somewhat resemble those of the Antarctic species Cellaria scoresbyi Hastings, 1946 (see Hayward & Thorpe 1989), but the cryptocysts of avicularia and autozooids in this species are densely granular over the entire surface and the opesia is situated closer to the centre of the autozooid.

Distribution. Bay of Plenty, West Coast Northland, 136–280 m depth.

Figures

FIGURE 8. Cellaria stenoryncha n. sp., TAN0413/109. A. Branch bifurcation with broader ovicellate internodes. B. Operculate autozooids and ovicellate zooids. C. Vicarious avicularium with mandible. Scale bars: A, 500 μm; B, 150 μm; C, 100 μm.