Stolarskicyathus pocilliformis, Cairns, 2004

Cairns, S. D., 2004, The Azooxanthellate Scleractinia (Coelenterata: Anthozoa) of Australia, Records of the Australian Museum 56, pp. 259-329 : 310-312

Stolarskicyathus pocilliformis n.sp.

Figs. 10L, 11A–E

Records/Types: Holotype: Franklin 03/99/D11, AM G16748 . Paratypes: Franklin 03/99/D10, 10, USNM 1008859 ; Franklin 03/99/D11, 56: 54 (including SEM 1012 ), USNM 1008860 , and 2, ZMUZ; Franklin 03/99/D12, 3, USNM 1008861 ; Franklin 03/99/D13, 5, USNM 1008862 . Type Locality: 20°14.49'S 151°47.53'E ( Marion Plateau , Queensland), 342 m.

Description. Corallum conical (ceratoid), having an eccentrically circular calice. Largest specimen (holotype) 5.47 mm in CD and 9.48 mm in height. Coralla opportunistic in attachment, having been found firmly attached to: foraminifera, shell fragments, rocks, bryozoan colonies, and sand grains. Basal plate approximately 1 mm in diameter, having a scalloped perimeter composed of 6 smaller outpocketings ( Fig. 11D), each bulge about 0.45 mm in diameter and corresponding to the region between each of the 6 S1. Just above these 6 protrusions the corallum narrows slightly to a diameter of 0.80– 0.85 mm, above which it expands at a constant angle of 18–20°, resulting in a H:D of 1.73–1.89. Epitheca finely transversely corrugated, as though lathed on a potter’s wheel. Corallum uniformly white.

Septa hexamerally arranged in 3 complete cycles (24 septa) according to the formula: S1>S2>S3, the third cycle developing at a CD of about 1.6 mm. No coralla examined had over 24 septa. S1 have vertical, slightly sinuous axial edges that fuse to the columella low in the fossa; rounded upper edges that rise to the level of the uppermost calicular edge; and outer edges that curve downward before meeting the theca, resulting in a well-developed thecal rim extending as much as 0.9 mm above the point at which the septa join the theca. This rim is divided into 24 longitudinal zones, each zone 0.6–0.7 mm wide and up to 0.7 mm thick ( Fig. 10L), the thickness resulting from internal stereome. These zones are covered with low rounded granules 30–35 µm in diameter and separated from each other by a narrow (65 µm) stria. In the centre of each zone is a septum, although the width of the septa is only about half the width of the zone. S2 about 85% width of an S1, of the same shape, and also having sinuous axial edges that fuse to the columella. S3 about 33% width of an S1, have sinuous axial edges, but do not fuse with the columella. All septal faces covered with pointed (75 µm tall) granules. Fossa of moderate depth, containing a robust, free-standing columella composed of 9–12 slender lamellae that are often slightly swirled. Axial edges of pairs of columellar lamellae sometimes fused, producing a V-shaped cross section ( Fig. 11A), and the columellar lamellae are sometimes interconnected in a labyrinthiform arrangement.

Remarks. Stolarski (1996) described and nicely illustrated a congeneric to this species from the Loyalty Islands (MUSORSTOM 6, DW 468), classifying it as an undescribed genus and species in his newly erectly family Gardineriidae Stolarski, 1996 . A specimen presumed to be the same as his undescribed species from off New Caledonia (MUSORSTOM 5–DW329: 20°22.90'S 158°46.50'E, 320 m, USNM 1008879) reveals that, although it is similar to S. pocilliformis , it differs in having a narrower corallum (H:D = 2.17); more exsert septa, which rise above the thecal rim; a lesser developed internal stereome; and occasionally black streaked epitheca. Stolarski (1996: 364) also implied that another species described and illustrated by Sieg & Zibrowius (1989: 192) from New Caledonia at 675–680 m (BIOCAL, DW 33) only as “a new species in a new genus of the Flabellidae ” may also belong to this genus. Specimens of that undescribed species are also present at the NMNH (from BIOCAL DW33, as well as six stations from the Bathus 4 expedition), but differ from both of those previously discussed in having a curved corallum with a truncate base (the result of transverse division), slender paliform lobes (P1–2?), slender columellar elements, and an elliptical calice. Thus, this as yet undescribed species is not considered to be congeneric.

Etymology. pocilliformis, Latin for “having the form of a small cup”.

Distribution. Known only from the Marion Plateau, Queensland, 342– 367 m.

SUBORDER DENDROPHYLLIINA