(Figs. 3 C–F, tables 1–3)
Deltocyathus moseleyi Cairns, 1979: 100, pl. 18, figs. 1−3.—Zibrowius 1980: 87, pl. 42, figs. A–K, pl. 43, figs. A–L.—Ramil Blanco & Fernández Pulpeiro 1990: 27.—Álvarez Claudio 1993: 417.—Álvarez Claudio 1994 c: 464.—Cairns & Chapman 2001: 35 (tab. 1).—Brito & Ocaña 2004: 383, pl. 82, figs. A–C.—Reveillaud et al. 2008: 322 (tab. 1), 325 (fig. 4).— Kitahara & Cairns 2009: 235 (tab. 1).—Altuna 2010: 21.—Louzao et al. 2010: S 1.
Material examined. Le Danois Bank, 2003: Stn. V 5, 544 m, three dead specimens. Le Danois Bank, 2008: Stn. D 6 V, 555 m, one specimen; Stn. R 1 R 2, 751 m, one dead specimen. Galicia Bank: Stn. R 2, 614 m, one specimen.
Description. Corallum unattached and solitary, discoid, small. Largest specimen examined has GCD= 1.44 cm and H= 0.6 cm (stn. R 2), but coralla are normally smaller (H= 0.40−0.47 cm; GCD= 1.28 – 1.16 cm, stn. V 5). Base almost hemispherical, with a central scar, costate. Costae arranged according to the formula C 1−2>C 3>C 4, reaching the central scar, prominent, well individualized by neat grooves that are deeper near calicular margin, finely granulated. Calices circular. Septa arranged hexamerally in six systems and four complete cycles (S 1 ≥S 2>S 3>S4, 48 septa); S 1 −S 3 reach de columella; S 1 and S 2 subequal in length, slightly longer than S 3, and S 3 than S 4. S 1 −S 3 paliferous, with P 1 −P 3 separated from the septa by a small notch and forming three crowns; P 3 tend to join to P 2 near columella. Septa and pali profusely granulated. Fossa very shallow, containing a small columella formed by a few straight rods. Corallum white (stn. D 6 V, R 2) to light brown (stn. R 1 R 2).
Remarks. The size of the specimen from stn. R 2 (GCD= 1.44 cm) is close to the biggest coralla known so far. Specimen from stn. R 1 R 2 has 52 septa and 52 costae, indicating an incomplete S 5. Due to the profuse ornamentation, and the closeness of septa and pali, calices appear particularly ‘full’ of radial elements.
Deltocyathus moseleyi and D. eccentricus are very similar and were keyed out recently by Kitahara & Cairns (2009). They are patellate to discoidal, unattached and solitary, parallel-sized coralla. In the ECOMARG surveys they never have been collected at the same stations although they frequently co-occur (Zibrowius 1980). As significant differences, specimens of D. moseleyi from Le Danois Bank and the Galicia Bank are massive, perfectly circular, with 48 stout septa arranged tightly and S 4 well developed. On the contrary, calices of D. eccentricus are irregular in oral view, with septa thinner and more loosely arranged, with S 4 more rudimentary. Their base is also different. Costae of D. moseleyi are rounded, finely granulated, well individualized, and set apart near margin by deep furrows. Costae of D. eccentricus are ridged, and they appear well individualized only near the calicular margin. The epicentre of the base is subtly pointed, whether in D. moseleyi there is a scar due to a transitory period of attachment to a substrate. Finally, exsertness of septa in D. eccentricus is unequal, with S 1 and S 2 similar, slightly more than S 3, and S 3 than S 4. In D. moseleyi, septa of all cycles are equally exsert.
As occasionally occurs in the species (Zibrowius 1980: 89), one specimen is regenerated (fig. 3 D).
Deltocyathus moseleyi is widely distributed in an area between the Celtic Sea, Azores and Madeira (Zibrowius 1980). It is probably common in the bathyal of the southern sector of the Bay of Biscay, and has been collected in the 2003, 2008 and 2009 ECOMARG expeditions. Nevertheless, specimens are never abundant. It was previously recorded by Zibrowius (1980) from Le Danois Bank.