Heterocyathus sulcatus (Verrill, 1866)

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

Heterocyathus sulcatus (Verrill, 1866)

Fig. 4E, F

Stephanoseris sulcata Verrill, 1866: 48. -Vaughan 1905: 416.

Psammoseris cyclicioides Tenison-Woods, 1879 (in part): 10-11, pl. 1, figs 1-5. -Tenison-Woods 1880: 299-300.

Heterocyathus pulchellus Rehberg, 1892: 8-9, pl. 1, fig. 7A-B.

Homophyllia incrustans Dennant, 1906: 161, pl. 6, fig. 3A-B.

Heterocyathus aequicostatus . -Folkeson 1919: 8-10 (in part), pl. 1, figs 4-7. - Boshoff 1981: 37 (in part).

Heterocyathus cyclicioides . - Wells 1964: 109.

Heterocyathus sulcatus . -Hoeksema and Best 1991: 231-233, figs 19-23. - Cairns 1998: 384. - Cairns 1999a: 98-99, figs A-D. - Cairns et al. 1999: 22. -Stolarski et al. 2001: 320. -Randall 2003: 135. -Cairns 2004a: 281-282, fig. 3K. - Cairns 2009: 13. - Kitahara and Cairns 2021: 531-533, figs 291H-J, 292.

Type locality.

Off Ceylon, Sri Lanka, depth unknown ( Verrill 1866).

Type material.

The holotype is deposited at the YPM ( Verrill 1866).

Material examined.

SAMC_A073054 (1 specimen): Eastern margin, 33 km from Richards Bay / 39 km off Mlalazi Estuary, 29°04'00.00"S, 32°10'00.00"E; 50 m . SAMC_A073071 (1 specimen): Eastern margin, 9 km from Shaka’s Rock / 13 km off Tongati Estuary, 29°34'23.87"S, 31°17'53.88"E; 60 m . SAMC_A073089 (1 specimen): Eastern margin, 67 km south of Ponta Do Ouro / 14 km off Mgobezeleni Estuary, 27°26'12.11"S, 32°44'12.11"E; 55- 60 m . SAMC_A073105 (1 specimen): Eastern margin, 36 km from Cape Vidal / 32 km off Mgobezeleni Estuary, 27°48'54.00"S, 32°38'24.00"E; 52 m . SAMC_A073108 (1 specimen): Eastern margin, 42 km south of Ponta Do Ouro / 27 km off Kosi Bay Estuary, 27°13'36.12"S, 32°49'18.11"E; 75 m . SAMC_A073123 (24 specimens): Eastern margin, 51 km from Shaka’s Rock / 41 km off Zinkwasi Estuary, 29°30'17.99"S, 31°45'44.99"E; 100- 105 m . SAMC_A073144 (1 specimen): Eastern margin, 35 km off Cape Vidal / 32 km off St Lucia Estuary, 27°49'41.87"S, 32°38'12.11"E; 54 m . SAMC_A073156 (1 specimen): Eastern margin, 35 km from Cape Vidal / 32 km off St Lucia Estuary, 27°49'41.87"S, 32°38'12.11"E; 54 m . SAMC_A073161 (1 specimen): Eastern margin, 26 km from Port St. Johns /off Bulolo Estuary, 31°49'59.99"S, 29°39'59.99"E; 140- 145 m . SAM_H1245 (15 specimens), SAM_H1430 (1 specimen): Locality data unknown. SAM_H1472 (2 specimens): Eastern margin, 2 km from Durban / 8 km off Umgeni Estuary, 29°52'00.00"S, 31°00'00.00"E; 99 m . SAM_H1512 (2 specimens): Eastern margin, locality data unknown; 55- 165 m . SAM_H3112 (7 specimens): Eastern margin, 9 km off Shaka’s Rock / 2 km off Tongati Estuary, 29°34'18.96"S, 31°11'05.25"E; 66 m. ORI_DIIIe1_2 (1 specimen): Locality data unknown.

Description.

Corallum unattached and variable in shape. All specimens examined encapsulate a gastropod shell. Shape of corallum correlates with size and shape of gastropod shell. Aboral efferent pore not exceeding 2.0 mm in diameter. Calice circular to elliptical (GCD:LCD = 1.0-1.1). Largest specimen examined (SAMC_A073161) 9.8 × 9.0 mm in CD, and 6.4 mm in H. Costae granulated, unequal in size with C3-4 wider than C1-2, and progressively diminishing in size towards base. Base smooth. Upper parts of corallum, columella, and S1-2 darker than other corallum elements.

Septa hexamerally arranged in four complete cycles according to the formula: S1 ≥ S2 > S3 > S4 (48 septa). S1 most exsert, extend to columella with sinuous axial margins and bear a well-developed pali (P1). S2 slightly less exsert and may be equal or less wide than S1. S2 also have sinuous axial margins bordered by a smaller pali. S3 least exsert, also with sinuous axial margins bordered by variable sized pali. S4 dimorphic in development: those adjacent to S1 being wider and more exsert than those adjacent to S2. Approximately 1/2 distance to columella each S4 fuses to adjacent S1-2 forming a V-shaped pattern. Pali cylindrical and bear meniane-like ridges. Fossa shallow, containing a papillose columella.

Distribution.

Regional: Eastern margin of South Africa, off Port St. Johns extending towards Kosi Bay Estuary (42 km south of Ponta Do Ouro: Mozambique); 50-164 m. Elsewhere: Indonesia (Hoeksema and Best 1991; Cairns 2004a); Australia ( Cairns 1998); Vanuatu; Wallis and Futuna Islands ( Cairns 1999a); New Caledonia ( Kitahara and Cairns 2021); 11-351 m.

Remarks.

Heterocyathus sulcatus differs from the other three South African congeners in having S3 > S4 as compared with S4 > S3 as in H. aequicostatus , H. alternatus , and Heterocyathus monileseptatum sp. nov. The presence of meniane-like structures on the palar faces of H. sulcatus further differentiates it from the other South African representatives. Part of the specimens reported herein were identified by Boshoff (1981) as H. aequicostatus , thus this account serves as a first record for the species in South African territory.

Figures

Figure 4. A, B Heterocyathus alternatus (ORI _ DIIIe 1 _ 1, locality data unknown) A calicular view B lateral view C, D Heterocyathus monileseptatum sp. nov. (SAM _ H 1431, off Durban Harbour, 99 m) C calicular view D lateral view E, F Heterocyathus sulcatus (SAMC _ A 073123, off Shaka's Rock, 100 - 105 m) E calicular view F lateral view G, H Labyrinthocyathus delicatus (SAM _ H 2836, off East London, 146 - 238 m) G calicular view H lateral view I, K Monohedotrochus capensis comb. nov. I, J (SAMC _ A 088924, off Kidds Beach, 247 - 147 m) I calicular view J lateral view K (SAM _ H 3210, off Scottburgh, 690 m) calicular view L, M Polycyathus sp. (USNM 91677, off Port Dunford, 69 m) L calicular view M full view N, O Rhizosmilia robusta (USNM 91689, off Kosi Bay Estuary, 74 m) N calicular view O lateral view P Solenosmilia variabilis (SAM _ H 3158, off Cintsa, 630 m) P full view. Scale bars: 10 mm (A-G, I-O); 100 mm (H, P).