Deltocyathus eccentricus Cairns, 1979

Altuna, Álvaro, 2013, Scleractinia (Cnidaria: Anthozoa) from ECOMARG 2003, 2008 and 2009 expeditions to bathyal waters off north and northwest Spain (northeast Atlantic), Zootaxa 3641 (2), pp. 101-128 : 110-111

Deltocyathus eccentricus Cairns, 1979

( Figs. 3 A–B, tables 1−3)

Deltocyathus eccentricus Cairns, 1979: 98 , pl. 18, figs. 8−11.—Zibrowius 1980: 86, pl. 40, figs. A–M, pl. 41, figs. A–N.— Cairns & Chapman 2001: 35 (tab. 1).—Brito & Ocaña 2004: 385, pl. 83, figs. A–E.—Kitahara & Cairns 2009: 235 (tab. 1).

Material examined. Galicia Bank: Stn. G 4, 750 m, six specimens, one of them dead; Stn. V 4, 732 m, 71 specimens, three of them dead; Stn. V 5, 877 m, 40 specimens, five of them dead; Stn. V 8, 780 m, two specimens alive and a fragment of a dead specimen.

Description. Corallum free and solitary (H= 0.41−0.51 cm, average= 0.45 cm for n= 30; GCD= 1.0− 1.36 cm, average= 1.22 cm for n=30, stn. V4), light, fragile, discoidal to faintly patellate. Base flat to slightly conical with a minute pointed elevation in the epicentre of base. Base costate; costae thin, delicate and finely granular, more developed near calicular margin, arranged according to the formula C1–2>C3>C4. Calices slightly irregular. Septa hexamerally arranged in four complete cycles (S1≥S2>S3>S4, 48 septa). S1 longer than S2, S2 than S3, and S3 much more than S4. S4 poorly developed; S3 joining with S2 close to the columella forming a delta, with additional more subtle unions between S4 and S3. Septa with axial edges slightly sinuous. Septal faces with small granules that tend to align vertically, occasionally also with fine vertical ridges. Pali in three crowns before S1−S3 (6P1, 6P2, 12P3), set apart from septa by a deep notch, sinuous, with small granules. P1 are the nearest to columella, then P2, and finally P3. Fossa shallow, containing a columella below pali level, spongy, with its surface formed by small rods. Corallum white or pinkish.

Remarks. First three cycles are already complete in coralla with GCD= 1.0 cm. In coralla of this size, S4 are very rudimentary and circumscribed to the calicular margin. Some coralla have supplementary septa (e.g., 52 septa). The junction S2−S3 is distinctive and occurs in the smallest specimens examined. In some specimens, width of C 3 may be similar to C1−C2.

Deltocyathus eccentricus is an amphiatlantic coral known also from the north-western Atlantic (Cairns 1979; Reyes et al. 2009). In the north-eastern Atlantic it is distributed between Azores, the Gorringe Bank, and the Cape Verde Islands (Zibrowius 1980) but rarely recorded. The Galicia Bank population is the northernmost known so far. Deltocyathus eccentricus is a new record for the “West coast of Spain and Portugal (J)” region (see Zibrowius 1980). It was also obtained in the Galicia Bank during the 1987 SEAMOUNT 1 expedition (Zibrowius, com. pers., unpublished). Although there are no Bay of Biscay records, its presence should be expected, particularly in its southern sector. Previous nearest occurrence to the Iberian Peninsula was at 35º37.5’N – 08º03.2’W (1716−1992 m depth, dead specimen, Zibrowius 1980).

Figures

FIGURE 3. Deltocyathus eccentricus Cairns, 1979 (stn. V 4, Galicia Bank). A) Corallum in calicular view (H = 0.46 cm; GCD = 1.36 cm). B) Same specimen seen from below. The slightly irregular profile of calice is distinctive. Deltocyathus moseleyi Cairns, 1979. C) Corallum in calicular view (H = 0.64 cm; GCD = 1.45 cm, stn. R 2, Galicia Bank). D) Same specimen seen from below. Notice regeneration in D. E) Corallum in calicular view (H = 0.4 cm; GCD = 1.16 cm, stn. V 5, Le Danois Bank). F) Same specimen seen from below. Scale bar: A – B = 0.7 cm; C – D = 0.7 cm; E – F = 0.5 cm.