Caryophyllia coronula, Cairns, Stephen D. & Polonio, Virginia, 2013

Cairns, Stephen D. & Polonio, Virginia, 2013, New records of deep-water Scleractinia off Argentina and the Falkland Islands, Zootaxa 3691 (1) : -

Caryophyllia coronula , n. sp.

Figs. 2 J–K, 9

Description. The corallum is ceratoid, straight or irregularly bent, and attached, the holotype measuring 13.5 x 12.4 in CD, 26.4 mm in height, and 2.6 mm in PD (broken); the PD:GCD ranges from 0.19–0.46. The calice is slightly elliptical (GCD:LCD = 1.06–1.17), the calicular margin being finely serrate (see below) but without lanceted septal groups. The theca is relatively thick, and the costae are poorly defined, flat, somewhat porcellaneous, and bears only very low granules or has a smooth texture; the C3 of the holotype are slightly convex. The entire corallum is white.

Septa are hexamerally arranged in four complete cycles (48 septa) according to the formula S1–2>S3>S4. The S1–2 are only slightly exsert (about 2 mm) and have straight, vertical axial edges that reach about 0.75 of the distance to the columella. S3 are about 1.7 mm exsert, have finely sinuous axial edges only on their lower half, and reach about 0.6 of the distance to the columella. The S4 are about 0.9 mm exsert, have straight axial edges, and reach about 0.4 of the distance to the columella. There are no ridges or undulations on the septal faces. The 12 P3 form a well-defined elliptical crown, each palus about 0.8–1.7 mm wide and having a finely sinuous outer edge and straight axial edge. The fossa is of moderate depth, containing a small fascicular columella consisting of only 2 or 3 twisted elements aligned in the axis of the GCD. Because of the small columella, the axial edges of the pali are close together, forming a small, tight palar crown.

Remarks. When Caryophyllia coronula is run through the key of all known Caryophyllia species (Kitahara et al. 2010), it comes closest to C. japonica Marenzeller, 1888 , both species having four cycles of hexamerally arranged septa, a relatively narrow pedicel, and S4 that are less wide than their S3. C. coronula differs primarily in having a much smaller columella, composed of few elements that are aligned with the greater axis of the calice, and a tighter palar crown, whereas the columella of C. japonica consists of an elliptical field of numerous elements and its palar crown is correspondingly larger. Furthermore, C. japonica is known only from the northern cold temperate region off Japan to the Commander Islands at depths of 77–1680 m. Within the South American cold temperate region, C. coronula is most similar to C. squiresi , differing in having a dense theca covered with granular costae (that of C. squiresi is thin, almost translucent, and smooth), slightly exsert septa (the septa of C. squiresi are nonexsert), and a smaller palar ring that encloses a smaller columella of linearly arranged elements.

Distribution. Known only from stations on the continental slope off Golfo San Jorge, Argentina, 797–1553 m ( Fig. 9).

Material/ Types: Holotype: PAT1108DR4, USNM 1193281. Paratypes: PAT0108DR1, 26, MNCN; PAT0108DR11, 1, MNCN, and 2 USNM 1193278 and 1193280; PAT0108DR13, 11, MNCN; PAT0108DR14, 1, MNCN; PAT1008DR1, 2, MNCN; PAT1008DR3, 3, MNCN; PAT1008DR4, 4, MNCN; PAT1008DR5, 1, MNCN; PAT1008DR10, 2, MNCN; PAT1008DR12, 8, MNCN 2.04/1110; PAT1108DR3, 2, MNCN 2.04/1108; PAT1108DR4, 1, MNCN; PAT1108DR9, 1, USNM 1193279, and 3, MNCN 2.04/1109; PAT0209DR1, 1, MNCN 2.04/1111; PAT0209DR14, 1, MNCN 2.04/1112.

Type locality. 46.962°S, 59.364°W (continental slope of Golfo San Jorge, off central Argentina), 1242 m.

Etymology. Named coronula (Latin for small crown), in allusion to the small palar crown that encircles the modest columella; treated as a noun in apposition.

Figures

FIGURE 2. A – C, Bathelia candida: A, PAT 1008 DR 5, rarely observed case of intratentacular budding; B – C, PAT 0210 DR 10, a calice and branch fragment, respectively. D – E, Caryophyllia antarctica, PAT 0209 DR 4, calicular and lateral views of corallum. F – G, C. squiresi, PAT 1208 DR 6, calicular and lateral views of corallum. H – I, C. kellerae, holotype, stereo calicular and lateral views of corallum. J – K, C. coronula, holotype, stereo calicular and lateral views of corallum. L – M, Crispatotrochus cornu, PAT 0209 DR 14, stereo calicular and lateral views of corallum.