Stephanocyathus moseleyanus Sclater 1886

Stephanocyathus moseleyanus (Sclater, 1886)

(Figs. 4 G–H, tables 1−3)

Stephanocyathus moseleyanus: Zibrowius 1980: 98, pl. 49, figs. A–K.—Álvarez Claudio 1993: 417.—Altuna Prados 1994a: 465, pl. 12, fig. D.—Altuna Prados 1994b: 55.—Altuna Prados 1994c: 78 (fig. 1).—Álvarez Claudio 1994c: 465.—Altuna 1995: 90.—Cairns & Chapman 2001: 37 (tab. 1).—Molodtsova et al. 2008: 118, fig. 2H.—Reveillaud et al. 2008: 322 (tab. 1), 325 (fig. 4).—Altuna 2010: 21.—Louzao et al. 2010: S1.

Material examined. Le Danois Bank, 2009: Stn. V 3, 999 m, a small, juvenile specimen.

Description. Corallum unattached, solitary, patellate, fragile, light and small (H= 0.4 cm; GCD= 1.73 cm). Base flat, with a small central scar of attachment, crossed by C1–C3 according to the formula C1≥C2>>C3. Costae poorly developed, discontinuous, not reaching the epicenter of base. Calice irregular in calicular view, with 48 septa arranged hexamerally in four cycles and six systems (S1>S2>S3>S4, 48 septa). S1 clearly dominant; S1 and S2 merge with columella; S3 join to S2 near columella; S4 very delicate and rudimentary, only developed near calicular margin, sometimes reduced to a few spines. Septal faces with small spines, particularly in S1 and S2. Inner margin of S1−S3 near columella with numerous small lobes. Fossa shallow, containing a columella that is a slightly concave compact mass. Corallum white.

Remarks. Young specimens of Stephanocyathus moseleyanus and S. crassus are difficult to distinguish. Nevertheless, the specimen examined is very similar to one depicted by Zibrowius (1980: pl.49, figs. F–G). Furthermore, S. moseleyanus is a coral relatively common in the Bay of Biscay, whereas S. crassus is extremely rare. Finally, depth of stn. V3 (999 m) is more in accordance with S. moseleyanus, typically found between 1000– 2000 m, than with S. crassus. This species occurs in a depth range of 400–1000 m depth, with most part of the records shallower than 900 m (Zibrowius 1980). The adults of similar size can be also difficult to differentiate, but the fifth cycle is much more developed in S. moseleyanus, whose corallum is also more massive (Zibrowius 1980).

A deep sea coral widely distributed in the north-eastem Atlantic and recorded also previously from Le Danois Bank by Zibrowius (1980).