Deltocyathoides sentus Kitahara & Cairns, 2021

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

Deltocyathoides sentus Kitahara & Cairns, 2021

Fig. 15E, F

Deltocyathus lens . -Gardiner and Waugh 1938: 198.

Deltocyathus italicus . - Zibrowius 1974a: 756-757.

Deltocyathus sp. A. - Cairns and Keller 1993: 245-246, fig. 5G, H.

Deltocyathus sentus Kitahara & Cairns, 2021: 101-102, figs 40, 41G-I.

Material examined.

USNM 91551 (1 specimen): Eastern margin, 33 km from SHAKA’S ROCK/ 34 km off Tongati Estuary, 29°44'17.99"S, 31°27'36.00"E; 300 m.

Description.

Corallum unattached, shaped as a bowl with a pointed epicentre base. Calice circular, with serrate calicular margin. Specimen examined 10.0 × 9.8 mm in CD, and 6.3 mm in H. Costae granular, rounded, wider near calicular margin, and progressively smaller in width toward base. Only C1-2 extend towards pointed base. Intercostal spaces deep, also being wider near calicular margin, and progressively getting narrower towards base. Corallum white.

Septa hexamerally arranged in four cycles according to the formula: S1> S2> S4> S3 (total of 48 septa). S1 most exsert, septa independent, bearing the largest and highest pali, which are separated from septa by a deep notch. Higher cycle septa (S2-4) becoming progressively less exsert. S2 slightly smaller than S1, also with a deep notch before a smaller palus. S3 ¾ the width of S2, with small pali. S4 ¼ wider than S3, with a pali slightly smaller than P2. P4 extend towards columella where it forms delta with adjacent P2. Sharp granules present on septal and palar faces. Moderately deep fossa, containing a papillose columella composed of a group of intertwined rods.

Distribution.

Regional: Eastern margin of South Africa, off Shaka’s Rock; 300 m ( Cairns and Keller 1993). Elsewhere: Zanzibar (Gardiner and Waugh 1938); Madagascar ( Zibrowius 1974a); New Caledonia ( Kitahara and Cairns 2021); 217-1400 m.

Remarks.

This taxon is based on the conical Deltocyathus species reported by Cairns and Keller (1993), who also suggested that it may be similar to the species mentioned by Zibrowius (1974a) from Madagascar. Cairns and Keller (1993) additionally emphasiszed the differences in the rounded and granular costae, relatively small P3, and moderately deep fossa; features with are in agreement with Deltocyathoides sentus Kitahara & Cairns, 2021 recently reported from New Caledonia. In addition; D. sentus can be distinguished from the only other congener ( D. orientalis ) by having a pointed epicentre, palar faces bearing lateral ridges, S3 being less wider that S4. The specimen reported herein therefore confirms that D. sentus can be found in shallow waters than previously reported ( Kitahara and Cairns 2021).

Figures

Figure 15. A, B Cyathotrochus pileus (SAMC _ A 087424, off Durban, 270 m) A calicular view B lateral view C, D Deltocyathoides orientalis (BIVa 2, locality unknown, 80) C calicular view D basal view E, F Deltocyathoides sentus (USNM 91551, off Shaka's Rock, 300 m) G, H Sphenotrochus (Eusthenotrochus) gilchristi (SAMC _ A 090086, off Cape Point, 24 m) G calicular view H lateral view I, J Sphenotrochus (Sphenotrochus) aurantiacus (SAM _ H 1416, off the Agulhas, 366 m) I calicular view J lateral view K, L Sphenotrochus (Sphenotrochus) evexicostatus (SAMC _ A 090085, locality data unknown, 43 m) K calicular view L lateral view M, N Sphenotrochus (Sphenotrochus) imbricaticostatus (USNM 91715 _ Holotype, off Kosi-Kumpungwini (Sifungwe) Estuary, 44 m) K calicular view L lateral view O, P Tropidocyathus lessonii (SAMC _ A 073218, off Kosi Bay Estuary, 74 m) O calicular view P lateral view. Scale bars: 10 mm (A-H, J-M, O-P); 2 mm (I, N).