Trochocyathus (Trochocyathus) sp. 3

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

Trochocyathus (Trochocyathus) sp. 3

Fig. 6M-P

Caryophyllia berteriana . - Gardiner 1904: 112-113.

Trochocyathus (Trochocyathus) sp. - Zibrowius 1982: 114, pl. 1, figs 1, 2.

Trochocyathus (Trochocyathus) sp. A. - Cairns and Keller 1993: 240, fig. 4C, D.

Material examined.

SAMC_A073157 (1 specimen): Eastern margin, 10 km from Port Edward / 24 km off Bilanhlolo Estuary, 31°05'48.11"S, 30°18'47.88"E; 140 m. SAMC_A073213 (1 specimen): Eastern margin, 29 km from Durban / 14 km off Mbokodweni Estuary, 30°06'24.12"S, 31°00'47.88"E; 160- 170 m. SAM_H3124 (1 specimen): Southern margin, 11 km from East London / 5 km off Gouda Estuary, 33°05'03.24"S, 27°49'33.40"E; 146- 238 m. USNM 91530 (3 specimens): Eastern margin, 37 km south of Ponta Do Ouro / 23 km off Kosi Bay Estuary, 27°11'03.59"S, 32°50'32.39"E; 100 m. USNM 91566 (1 specimen): Eastern margin, 42 km south of Ponta Do Ouro / 27 km off Kosi Bay Estuary, 27°13'30.00"S, 32°49'30.00"E; 74 m.

Imagery data.

BMNH 1939.7.20.47 (1 specimen): Eastern margin, 20 km from Richards Bay/8 km off Nhlabane Estuary, 28°40'00.00"S, 32°15'00.00"E; 165 m.

Description.

Corallum ceratoid, mostly attached to substrate through a narrow pedicel (PD:GCD = 0.4-0.6) and a thin encrusting base. Calice circular to slightly elliptical (GCD:LCD = 1.0-1.1), calicular margin slightly serrate. Largest specimen examined (USNM 91566) 8.2 × 7.3 mm in CD, and 9.0 mm in H. Costae prominent and bearing small granules near calicular margin, and progressively disappear towards pedicel. Theca becomes transversely ridged beyond 3 mm from calicular margin. Corallum white, and sometimes light brown around calicular margin.

Septa hexamerally arranged in four cycles according to the formula: S1 ≥ S2 > S3 ≥ S4 (48 septa). However, largest specimen (USNM 91566) displays S1-2 > S4-3. S1 most exsert and extend slightly further into centre of calice than S2. S1 axial margins straight to slightly sinuous. S2 equally wide or ¼ less wide than S1, with moderately sinuous axial margins. Higher cycle septa (S3-4) progressively less exsert (if at all). S3 with most sinuous axial margins. S4 rudimentary and bear straight to slightly sinuous axial margins. Pali present before all but last septal cycles. P2-3 joining deeper in fossa, forming a chevron-like structure before S2. Septal and palar faces finely granulated. Fossa moderately deep, pali indistinguishable from the closely-packed rods of the papillose columella.

Distribution.

Regional: Southern to eastern margin of South Africa, from East London extending towards Kosi Bay Estuary (37 km south of Ponta Do Ouro: Mozambique); 74-170 m. Elsewhere: Mozambique, Madagascar, and Saya de Malha Bank; 74-315 m ( Cairns and Keller 1993).

Remarks.

The examined specimens closely resemble Trochocyathus (T.) sp. A reported by Cairns and Keller (1993) in all features, except for its septa all having sinuous axial margins instead of only S3 having sinuous axial margins. Zibrowius (1982) also noted a Trochocyathus specimen (BMNH 1939.7.20.47) that resembles Cairns and Keller’s (1993) specimens in all septa being straight except S3 and in septa being arranged according to S1-2 > S4-3. The representative images of BMNH 1939.7.20.47 unfortunately do not show the tertiary septa’s axial margin, and for that reason this Trochocyathus specimen is added to the records of species accounted for here. Nevertheless, a new name will not be introduced until the variation within Trochocyathus (T.) rawsonii is better understood.

Figures

Figure 6. A, B Trochocyathus (Trochocyathus) sp. 1 (SAM _ H 1449, off Mazeppa Bay, 174 m) A calicular view B lateral view C, F Trochocyathus (Trochocyathus) sp. 2 C, D (SAM _ H 1388, East London, 90 m) C calicular view C lateral view E, F (SAM _ H 1407, off Mosselbaai, 192 m) E calicular view F lateral view G, L Trochocyathus (Trochocyathus Trochocyathus) sp. cf. Trochocyathus Trochocyathus rawsonii Guynia sensu Cairns & Keller, 1993 G, J (SAM _ H 1440, off East London, 90 m) G calicular view H lateral view I calicular view J lateral view. 1993 K, L (SAMC _ A 090156, off Sedgefield, 74 m) K calicular view L lateral view M, P Trochocyathus (Trochocyathus) sp. 3 M, N (SAM _ H 3124, off East London, 90 m) O calicular view P lateral view O, P (BMNH 1939.7.20.47, off Richards Bay, 165 m) O calicular view P lateral view. Lateral view. Scale bars: 10 mm.