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
treatment provided by
Fig. 6G-L View Figure 6
Off Barbados, eastern Caribbean Island (USCSS ‘Hassler’); 183 m ( Cairns 1979).
Three syntypes are deposited at the MCZ ( Cairns 1979).
DEFF/SAEON_ A32823 View Materials (1 specimen): Southern margin, 131 km from Gouritsmond /off Goukamma Estuary, 35°14'57.1"S, 22°50'48.1"E; 511 m. GoogleMaps 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. GoogleMaps 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. GoogleMaps 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. GoogleMaps 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. GoogleMaps 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. GoogleMaps 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. GoogleMaps 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. GoogleMaps 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. GoogleMaps 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. GoogleMaps 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. GoogleMaps 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. GoogleMaps 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. GoogleMaps 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. GoogleMaps
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.
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.
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).
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