Deltocyathus crassiseptum Cairns 1999

New Caledonia from 21°00.83’S, 164°27.34’E to 24°44’S, 168°06’E (Kitahara & Cairns, 2009), 370-583 m; Wallis and Futuna region (Cairns 1999), 420- 510 m; Vanuatu region (Cairns 1999), 413-536 m.

Corallum circular to slightly elliptical shaped as a shallow bowl. T eca thick. Base fl at to slightly convex, usually with a scar, and sometimes protuberant. Small coralla show a CD:HT ratio near 2. Costae unequal and more prominent at calicular edge where they are separated by intercostal grooves bisected by a row of low and rounded granules that sometimes resemble a small ridge in the valley formed by the adjacent costae. C1-2 broader than other costae. Corallum white to reddish-brown. Septa hexamerally arranged in four cycles (48 septa) with septal formula: S1>S2>S3>S4. However, in larger coralla up to 3 pairs of S5 are present re- sulting in 56 septa. S1 thick and most exsert septa, extending half distance to columella and bear a dimorphic lamellar paliform lobe. Those paliform lobes before the two principal S1 are narrower than the other four P1, but all reach the columella. S2 equal to slightly smaller and less exsert than S1, also bearing a paliform lobe that reaches columella by a small paliform teeth. S3 about ¾ width of S2, bearing a tall recessed pali that fuses P2 in a chevron arrangement typical of the genus. S4 smallest septa and in some coralla composed by a row of spines. All septal and palar faces very granular. Fossa shallow to moderately deep, containing a papillose columella.

azooxanthellate

413-536 m