Deltocyathus rotulus (Alcock, 1898)

Filander, Zoleka N., Kitahara, Marcelo V., Cairns, Stephen D., Sink, Kerry J. & Lombard, Amanda T., 2021, Azooxanthellate Scleractinia (Cnidaria, Anthozoa) from South Africa, ZooKeys 1066, pp. 1-198 : 1

publication ID

https://dx.doi.org/10.3897/zookeys.1066.69697

publication LSID

lsid:zoobank.org:pub:133CE040-A5AF-44F1-BC9A-558C2F06A8AA

persistent identifier

https://treatment.plazi.org/id/0E3B782C-20EA-1865-8574-D593767BC70B

treatment provided by

ZooKeys by Pensoft

scientific name

Deltocyathus rotulus (Alcock, 1898)
status

 

Deltocyathus rotulus (Alcock, 1898)

Fig. 7E, F View Figure 7

Trochocyathus rotulus Alcock, 1898: 16, pl. 2, figs 1, 1A.

Deltocyathus fragilis Alcock, 1902a: 99, 100. - Alcock 1902c: 21, pl. 1, figs 15, 15A.

Deltocyathus rotulus . -van der Horst 1931: 6. -Gardiner and Waugh 1938: 196. - Yabe and Eguchi 1937: 129. -Keller 1982: 50. - Cairns and Keller 1993: 245, pl. 5, fig. I. -Cairns 1994: 55, 56, pl. 24, figs J, K. - Cairns and Zibrowius 1997: 125, 126, fig. 16A-C. - Cairns 1999a: 91-92. -Cairns 2004a: 280. -Kitahara and Cairns 2009: 238, fig. 1B. - Kitahara and Cairns 2021: 399, 401, figs 204, 216A-D.

Type locality.

North of Maldive Atoll, Flores Seas (HMS ‘Investigator’ stn. 216: 7°24'S, 118°15.2'E); 794 m ( Alcock 1898; Kitahara and Cairns 2009).

Type material.

The holotype is presumed to be deposited at the IM (Cairns 2004a; Kitahara and Cairns 2009).

Material examined.

USNM 91550 (1 specimen): Eastern margin, 28 km from Scottburgh/ 21 km off Mkomazi, 30°11'59.99"S, 32°01'00.00"E; 1360 m.

Description.

Corallum discoidal, unattached, with a flat to slightly bowl-shaped base. Calice slightly elliptical (GCD:LCD = 1.2), with a lanceted and scalloped calicular margin. Specimen examined 30.4 × 25.5 mm in CD. All costae serrated and prominent at calicular margin. Intercostal spaces deep and wider at calicular margin, becoming progressively narrower towards base. Costae granular, resulting in a serrated costal margin. Corallum white, being light reddish brown around columella.

Septa hexamerally arranged in five cycles according to the formula: S1-2 > S3 > S4 > S5 (total of 96 septa). S1-2 appearing independent septa, but fusing to neighbouring septa through porous connections. S1-2 moderately exsert, bear pali, each of which is separated from its septum by a notch. S3 ¾ the width of S1-2, less exsert, and sometimes each bearing a small palus. S4 less wide than S3, but equally exsert, and each bearing a tall palus, which form a distinctive crown around columella. S5 rudimentary. All septa fuse to adjacent septa, but position of fusion varies: S1-4 join neighbouring septa near columella whilst S5 join S4 near calicular margin. P1-3 small, with P1-2 being ¼ or ½ the size of P4, and P3 consistently half the size of P1-2, positioned at porous fusions. P4 positioned further away from columella, alluding to a crown of 24 pali. Upper margins of all septa smooth. Fossa shallow, containing a papillose columella composed of irregularly shaped papillae.

Distribution.

Regional: Eastern margin of South Africa, off Scottburgh; 1360 m. Elsewhere: Mozambique; Zanzibar ( Cairns and Keller 1993); Maldives ( Alcock 1898; Gardiner and Waugh 1938); Gulf of Aden (Gardiner and Waugh 1938); Sri Lanka (van der Horst 1931); Tanzania (Gardiner and Waugh 1938); Japan (Cairns 1994); Philippines; Indonesia; Malaysia ( Alcock 1902c; Cairns and Zibrowius 1997); Vanuatu; Wallis, and Futuna region ( Cairns 1999a); Australia (Cairns 2004a); New Caledonia (Kitahara and Cairns 2009, 2021); 210-2340 m.

Remarks.

Among the Deltocyathus s from South Africa, the Indo-Pacific D. rotulus differs from the Atlantic D. italicus in having a large and discodial corallum, a total of five cycles of septa (the highest cycle sometimes incomplete), costae giving a serrated appearance, and the reddish brown pigmentation around the columella.

Kingdom

Animalia

Phylum

Cnidaria

Class

Anthozoa

Order

Scleractinia

Family

Deltocyathidae

Genus

Deltocyathus

Loc

Deltocyathus rotulus (Alcock, 1898)

Filander, Zoleka N., Kitahara, Marcelo V., Cairns, Stephen D., Sink, Kerry J. & Lombard, Amanda T. 2021
2021
Loc

Deltocyathus fragilis

Alcock 1902
1902