Trochocyathus (Trochocyathus) sp. 1

Figs 5O, P, 6A, B

Trochocyathus rawsonii . - Gardiner 1904: 100-103, 124, pl. 1, fig. 2A, B, pl. 2, fig. D, E, G, H, J, K. - Cairns and Keller 1993: 241.

Caryophyllia gigas . - Boshoff 1981: 36.

Endopachys grayi . - Boshoff 1981: 42 (in part).

Material examined.

SAMC_A073233 (2 specimens): Southern margin, 14 km from Cape Point / 10 km off Buffels Wes Estuary, 34°13'59.99"S, 18°30'00.00"E; 42 m. SAM_H1244 (1 specimen): Southern margin, 7 km from East London / 5 km off Buffalo Estuary, 33°02'59.99"S, 27°56'59.99"E; 59 m. SAM_H1449 (1 specimen): Southern margin, 14 km from Mazeppa Bay / 20 km off Great KeiEstuary, 32°34'00.00"S, 28°33'00.00"E; 174 m. SAM_H3115 (1 specimen): Southern margin, 2 km off Mosselbaai / 10 km off Hartenbos Estuary, 34°10'37.57"S, 22°09'19.14"E; 55 m. SAM_H3117 (1 specimen): Southern margin, 246 km from Mazeppa Bay / 243 km off Mendu Estuary, 33°43'11.99"S, 30°48'47.99"E; 780 m. SAM_H3177 (2 specimens): Southern margin, 15 km from Port Alfred / 11 km off Riet Estuary, 33°39'18.00"S, 27°11'35.99"E; 90 m. SAM_H3833 (1 specimen): Eastern margin, 34 km from Coffee Bay / 7 km off Ntlonyane Estuary, 32°15'11.99"S, 28°57'42.00"E; 47 m. SAM_H3834 (1 specimen): Southern margin, 23 km from Port Elizabeth / 22 km off Bakens River Estuary, 33°50'41.99"S, 25°47'30.00"E; 36 m. ORI_DIIIa4_3 (1 specimen): Locality data unknown, 300 m. ORI_EId1 (2 specimens): Eastern margin, other locality data unknown. USNM 77220 (3 specimens): Eastern margin, 28 km from Coffee Bay / 19 km off Bulungulu Estuary, 32°14'53.99"S, 29°10'23.99"E; 620- 560 m.

Imagery data.

BMNH 1950.03.22.17 (1 specimen), BMNH 1950.01.10.112 (1 specimen), NHMUK 1970.01.26.11-20 (2 specimens): South Africa, other locality data unknown. Mortensen Java Expedition (12 specimens): Eastern margin, off Durban, 128 m.

Description.

Corallum solitary, ceratoid to trochoid, mostly attached through a variably sized pedicel (PD:GCD = 0.3-0.7). Calice circular to slightly elliptical (GCD:LCD = 1.0-1.1), calicular margin slightly serrated. Largest specimen examined (ORI_DIIIa4_3) 11.1 × 10.1 mm in CD, 12.0 mm in H, and 6.6 mm in PD. Costae prominent from calicular margin to base, similar in width to associated septa, equidistant, low, bearing small granules, and separated by thin intercostal furrows. Corallum white.

Septa hexamerally arranged in four cycles according to the formula: S1 ≥ S2> S3> S4 (48 septa); sometimes a pair of S5 present in a half-system (e.g., ORI_EId1). S1 most exsert, equal or slightly wider than S2, with straight or slightly sinuous axial margin. S2 ¼ wider than S3 with moderately sinuous axial margin. S3 as sinuous as S2. S4 rudimentary and bearing dentate axial margin. S3-4 progressively less exsert than S2. Pali present before all but last septal cycle. P2-3 joining deeper in fossa, forming thick chevrons before S2. Pali tall, being distinctively higher than columellar elements. All septal and palar faces covered with small granules. Fossa moderately deep, containing a papillose columella composed of a group of 6-18 loosely-packed, low-profile rods.

Distribution.

Regional: Southern to eastern margin of South Africa, from off Cape Point towards Coffee Bay; 36-780 m.

Remarks.

The validity of Gardiner’s (1904) specimens as Trochocyathus (T.) rawsonii has long been questioned due to their well-developed costae, slender pedicel, and rarely bearing S5 (Cairns 1979; Zibrowius and Gili 1990; Cairns and Keller 1993). The examined material conforms to these characteristics and closely resembles Gardiner’s (1904) illustrations. Nevertheless, the specimens reported herein, together with Gardiner’s (1904), might represent a new species. However, as Trochocyathus have great intraspecific variation, a formal description is postponed. Nonetheless, these new records extend the known distribution of this taxon towards the eastern margin of South Africa and also expand its known depth range (both upper and lower).