Trochocyathus, Milne-Edwards & Haime, 1848

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 Trochocyathus Trochocyathus Trochocyathus rawsonii Guynia sensu Cairns in Cairns & Keller, 1993

Fig. 6G-L

Trochocyathus rawsonii Guynia sensu Cairns 1979: 77, fig. 6, pl. 13. - Cairns and Keller 1993: 241-242, figs 4E, H.

Type locality.

Off Barbados, eastern Caribbean Island (USCSS ‘Hassler’); 183 m ( Cairns 1979).

Type material.

Three syntypes are deposited at the MCZ ( Cairns 1979).

Material examined.

DEFF/SAEON_ A32823 (1 specimen): Southern margin, 131 km from Gouritsmond /off Goukamma Estuary, 35°14'57.1"S, 22°50'48.1"E; 511 m. SAMC_A073015 (1 specimen): Southern margin, 32 km from Mazeppa Bay / 19 km off Mendu Estuary, 32°25'00.11"S, 28°58'18.11"E; 330- 340 m. SAMC_A073206 (2 specimens): Eastern margin, 36 km from Richards Bay / 49 km off Nhlabane Estuary, 29°02'12.11"S, 32°19'36.12"E; 760- 800 m. SAMC_A073220 (1 specimen): Southern margin, 13 km from Port St. Johns / 12 km off Bulolo Estuary, 31°44'48.12"S, 29°33'00.00"E; 370 m. SAMC_A090091 (1 specimen): Eastern margin, 152 km from Margate /off Bilanhlolo Estuary, 31°39'07.00"S, 29°39'42.00"E; 300- 540 m. SAMC_A090156 (3 specimens): Southern margin, 14 km from Sedgefield /off Cunge Estuary, 34°09'17.46"S, 22°48'37.32"E; 74 m. SAM_H1360 (1 specimen): Southern margin, 11 km from East London / 3 km off Buffalo Estuary, 33°00'53.67"S, 27°55'50.67"E; 128 m. SAM_H1415 (1 specimen): Southern margin, 8 km from Pringle Bay / 6 km off Buffels Oos Estuary, 34°17'55.37"S, 18°49'10.85"E; 33 m. SAM_H1440 (3 specimens): 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. SAM_H3110 (26 specimens): Eastern margin, 18 km from Cape Vidal / 27 km off Mfolozi Estuary, 28°16'18.00"S, 32°38'48.00"E; 670 m. SAM_H3113 (2 specimens): Southern margin, 11 km from East London / 3 km off Buffalo Estuary, 33°00'53.67"S, 27°55'50.67"E; 128 m. SAM_H3171 (8 specimens): Southern margin, 40 km from Cintsa Mouth / 29 km off Cwili Estuary, 32°55'00.00"S, 28°31'00.00"E; 630 m. SAM_H3174 (1 specimen): Southern margin, 22 km from Gonubie / 21 km off Gqunube Estuary, 33°06'00.00"S, 28°08'17.99"E; 700- 650 m. SAM_H3829 (1 specimen): Southern margin, 98 km from Gansbaai / 103 km off Buffels Oos Estuary, 35°15'18.00"S, 18°39'18.00"E; 547 m.

Description.

Corallum ceratoid to trochoid, attached to a narrow pedicel (PD:GCD = 0.3-0.5). Calice circular to slightly elliptical (GCD:LCD = 1.0-1.3), calicular margin slightly serrate. Largest specimen examined (SAM_H3113) 12.2 × 11.2 mm in CD, 4.9 mm in PD, and 17.5 mm in H. Costae prominent and bearing small granules near calicular margin, progressively becoming narrower towards base. Costae separated by deep furrows. Corallum white, but sometimes purplish with white columella.

Septa hexamerally arranged in four cycles according to the formula: S1 ≥ S2 > S3 > S4 (48 septa). S1-2 usually equally exsert, but sometimes S2 may be slightly less exsert than S1. S1 meets columella with straight to slightly sinuous axial margins. S1 slightly wider to equal in width to S2. S2 axial margins straight to slightly sinuous. Higher cycle septa (S3-4) progressively less exsert. S3 ~ ¼ less wide than S2, with moderately sinuous axial margins. S4 ½ the width of S3, and bear extremely sinuous and sometimes dentate axial margins. Pali present before all but last septal cycle, being taller than columellar elements, slightly sinuous, and thick, with some half-systems having P2-3 joining in front of S2 before extending towards columella. All septal and palar faces being granulated. Fossa moderately deep, containing a papillose columella composed of a group of low-profile and compact intertwined rods.

Distribution.

Regional: Southern to eastern margin of South Africa, from off Pringle Bay extending towards Cape Vidal; 33-800 m. Elsewhere: north-western Madagascar and off Walter Shoal ( Cairns and Keller 1993); 760-780 m.

Remarks.

Although specimens resemble Gardiner’s (1904) Trochocyathus (T.) sp. in having four cycles with the following septal formula S1 ≥ S2 > S3 > S4, they differ in S4 consistently bearing sinuous to dentate axial margins unlike the exclusively dentate appearance observed in Gardiner’s (1904) representatives. The level of granulation on septal and palar faces may also distinguish the two forms, of which Trochocyathus (T.) sp. cf. T. rawsonii Guynia sensu Cairns and Keller (1993) has low coverage appearance (with large granules prominent along the septal faces) as compared with the fine and dense granules throughout both the pali and septa (giving specimens a rough appearance) in Gardiner’s (1904) Trochocyathus forms. Furthermore, the pali are compact in Trochocyathus (T.) sp. cf. T. rawsonii Guynia sensu Cairns and Keller (1993) rather than being loosely packed ( Trochocyathus (T.) sp. 1 cf. T. rawsonii Guynia sensu Gardiner (1904)). However, some specimens of Trochocyathus (T.) sp. cf. T. rawsonii Guynia sensu Cairns and Keller (1993) diverge from the typical compact pali, thus bearing a tall and thin pali (SAM_H1415 and SAMC_A090156).

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.