Deltocyathus crassiseptum Cairns, 1999

Kitahara, Marcelo V. & Cairns, Stephen D., 2009, A revision of the genus Deltocyathus Milne Edwards & Haime, 1848 (Scleractinia, Caryophylliidae) from New Caledonia, with the description of a new species, Zoosystema 31 (2), pp. 233-248 : 244

Deltocyathus crassiseptum Cairns, 1999 ( Fig. 1H)

Deltocyathus crassiseptum Cairns, 1999: 94 , fig. 12c-f.

TYPE MATERIAL. — The holotype and 78 paratypes are deposited at the MNHN (uncatalogued), and 39 at the USNM (98681 [2], 98682 [9], 98683 [13], 98684 [8], 98685 [2], 98686 [5]).

TYPE LOCALITY. — 19°21’S, 169°25’E (Tanna), 433- 450 m.

NEW RECORDS. — BATHUS 3, stn CP 818, 4 specimens (MNHN-Scl.2008-0024). — BATHUS 4, stn CP 889, 1 specimen (MNHN-Scl.2008-0026). — HALIPRO 1, stn CP 877, 1 specimen (MNHN-Scl.2008- 0025). — NORFOLK 2, stn DW 2041, 2 specimens (MNHN-Scl.2008-0027); stn DW 2024, 6 specimens (MNHN-Scl.2008-0028); 6 specimens ( USNM 1114122 ) ; stn DW 2025, 1 specimen (MNHN-Scl.2008-0029); stn DW 2097, 2 specimens (MNHN-Scl.2008-0030); stn DW 2117, 2 specimens (MNHN-Scl.2008-0031).

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

DESCRIPTION

Corallum circular to slightly elliptical shaped as a shallow bowl.Theca thick.Base flat to slightly convex, usually with a scar, and sometimes protuberant. Largest specimen examined (BATHUS 3, stn CP 877) 14.2 mm in calicular diameter and 4.6 mm in height. However, smaller 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 resulting 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 P 2 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.

REMARKS

First time reported since the original description, the specimens of D. crassiseptum are distinguished from the New Caledonia congeners by having: a slighty thicker S 1-2 in relation to the other septa, corallum shaped as a bowl, absence of costal spines, well-arranged crowns formed by the paliform lobes, and paliform lobes and columellar elements that terminate below the septa upper edges. Different pigmentation patterns can be found in New Caledonia specimens of D. crassiseptum : some have the entire calicular edge and septa reddish-brown, other specimens present only the S3 and paliform lobes pigmented, some are completely pigmented and some are enterely white.