Abyssoecia elevata n. sp.

(Figs 2G, H, 13–15)

Material examined. Holotype: ZIRAS 1/50703, colony detached from nodule, YMG R.V. Yuzhmorgeologiya cruise YMG4–13, Stn 302, 30 July 2014, 13.16460° N, 132.52885° W, 4934 m. Paratype 1: ZIRAS 2/50704, colony detached from nodule, YMG R.V. Yuzhmorgeologiya cruise YMG4–06, Stn 106, 2 September 2006, 13.26750° N, 134.51797° W, 4805 m. Paratype 2: ZIRAS 3/50705, colony attached to particle of nodule, YMG R.V. Gelendzhik cruise GLD4–09, Stn 191, 3 January 2011, 13.40957° N, 133.47513° W, 4897 m. Paratype 3: ZIRAS 4/50706, colony fragment (with gonozooid) detached from nodule, YMG R.V. Yuzhmorgeologiya cruise YMG4–13, Stn 282, 12 July 2014, 13.41580° N, 132.28818° W, 4946 m. Additional material: YMG4–04, Stn 44; YMG4–06, Stn 99; YMG4–07, Stns 129, 135; GLD4–09, Stn 196; YMG4–13, Stn 313. Total specimens examined 11.

Etymology. Latin, elevatus, raised, alluding to the elevation of colony above the substratum.

Description. Colony suberect to erect, flabellate (Fig. 13), pale lemon yellow (Fig. 2G, H), supported by founding zooids and additional pillars derived from autozooids (Figs 13B, F, 15C–I); up to 5.77 mm long and 9.09 mm wide. Arcuate lateral margins of large colonies tending to curve proximad, occasionally meeting around a space or spaces, creating open calyciform shape (Figs 2G, 13A). Supportive pillars of about 4–8 connate zooids, each budded in such a way as to be bent, with proximal portion subvertical, descending towards substratum (e.g. Fig. 15F), and frontodistal part forming peristomial tubes (e.g. Fig. 15I). No kenozooids. Surface calcification of colony forming sinuous concentric striae (Figs 13D, 14A, E–J) and having fibrous (planar-spherulitic) microstructure (Fig. 14K); pseudopores small, simple, sparse, evenly distributed.

Frontal surface with evenly distributed autozooidal peristomes, all obliquely inclined in direction of colony growth, generally longer towards colony margin, fully formed apertures mostly circular (Fig.14J), calcified terminal diaphragms rare. New zooids budded from part of distobasal wall of preceding zooid (Fig. 14G, H), hence zooids partly overlapping. Interior wall surface of imbricated foliated fabric of wedge-shaped crystallites; no spinules (Fig. 14K).

Gonozooid simple, transversely reniform (Fig. 14A), wedged in among autozooidal peristomes at colony margin, moderately densely pseudoporous, narrow ooeciostome directed outwards, with more or less circular ooeciopore (Fig. 14B–E).

Ancestrula (Figs 14L–N, 15D–I, K), suberect, inclined at 50–60° angle to substratum. Protoecium typically flared at base, narrowing at base of peristome but no distinction in surface calcification of needle-like crystallites; peristome tending to be angled to one side (Figs 14L, 15H, I). Later daughter zooids tending to form descending outgrowths to substratum, helping to support ancestrula as colony grows; no basal kenozooids.

Measurements (mm). Holotype, ZIRAS 1/50703 (Fig. 13A–B): Colony length 3.28, width 4.88, height 2.79; ZL 0.597–0.802 (0.711 ± 0.074); PeL 0.062–0.191 (0.108 ± 0.037); PeD 0.148–0.185 (0.171 ± 0.012); ApL 0.136–0.165 (0.149 ± 0.008); ApW 0.124–0.143 (0.133 ± 0.006).

Paratype 3, ZIRAS 4/50706 (Fig. 14A–E): Gonozooid (n = 1): GZL 0.703; GZW 0.880; GZH 0.383; OsL 0.155; OsD 0.133; OpD 0.111.

Non-type specimen YMG4–04, Stn 44 (Figs 14L–M, 15G–K): Ancestrula (n = 1): AnH 0.903; AnPeD 0.221; AnPrL 0.247; AnPrW 0.234.

Remarks. Eleven colonies, representing a range of sizes, were isolated from the nodule samples; only one was fertile. The elevated, flabellate form of the colony is consistent, with the pillar-like supports providing stability as the colony expands.

Distribution. Recorded from 10 stations within coordinates 13.09421– 13.49873° N, 130.80695– 134.72239° W, at depth range 4787–5050 m.