Flabellum (Flabellum) leptoconus Cairns & Zibrowius, 2016

Fig. 11C, D

Flabellum sibogae Gardiner, 1904: 98. - Cairns and Keller 1993: 220, 221.

Adkinsella sp. - Boshoff 1981: 34.

Flabellum (Flabellum) leptoconus Cairns & Zibrowius, 2016: 161-162, fig. 1F, J.

Type locality.

South of Natal region, South Africa (USNM 62498: 31°23'00"S, 29°54'00"E); 409-440 m (Cairns and Zibrowius 2016).

Type material.

The holotype and three paratypes are deposited at the NMNH (Cairns and Zibrowius 2016), whilst one paratype is deposited at ORI.

Material examined.

ORI_DIIa1 (1 specimen: paratype): Southern margin, 44 km from Port St. Johns / 4 km from Mkweni Estuary, 31°22'59.99"S, 29°53'59.99"E; 409- 440 m. DSCS INV-358 (2 specimens): Southern margin, 92 km from Oubosstrand / 89 km off Tsitsikamma Estuary, 34°53'21.93"S, 24°06'56.47"E; 355 m. DSCS-INV 569 (2 specimens): Southern margin, 65 km from Cape St. Francis / 70 km from Slang Estuary, 34°47'05.01"S, 24°45'42.30"E; 392 m. SAMC_A073153 (2 specimens): Eastern margin, 19 km from Coffee Bay / 18 km off Mdumbi Estuary, 32°02'53.87"S, 29°19'41.87"E; 250- 280 m. SAMC_A073179 (1 specimen): Southern margin, 34 km from Mazeppa Bay / 17 km off Mendu Estuary, 32°23'35.88"S, 28°59'12.11"E; 295- 350 m. SAMC_A073190 (4 specimens): Southern margin, 34 km from Mazeppa Bay / 17 km off Mendu Estuary, 32°23'35.88"S, 28°59'12.11"E; 295- 350 m. SAMC_A090154 (1 specimen): Southern margin, 58 km from Port Alfred / 35 km off Mgwalana Estuary, 33°39'10.19"S, 27°29'57.58"E; 304 m. SAM_H1239 (1 specimen): Southern margin, 26 km from Cape Point / 20 km off Sand Estuary, 34°10'22.29"S, 18°39'51.94"E; 567 m. SAM_H2841 (1 specimen): Eastern margin, 20 km from Cape Vidal / 23 km off St Lucia Estuary, 27°59'29.99"S, 32°40'47.99"E; 550 m. SAM_H3150 (1 specimen): Southern margin, 48 km from Port Alfred / 19 km off Mgwalana Estuary, 33°32'59.99"S, 27°22'59.99"E; 80 m. SAM_H3180 (2 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. SAM_H3181(I specimen): Eastern margin, 30 km from Scottburgh / 20 km off Fafa Estuary, 30°33'23.99"S, 30°48'35.99"E; 690 m. SAM_H3182 (24 specimens): Southern margin, 40 km from Cintsa / 29 km from Cwili Estuary, 32°54'59.99"S, 28°30'59.99"E; 630 m. SAM_H3183 (7 specimens): Southern margin, 32 km off Mazeppa Bay / 24 km off Kobole Estuary, 32°28'36.00"S, 28°58'48.00"E; 710- 775 m. SAM_H3184 (4 specimens): Southern margin, 22 km from Gonubie / 21 km off Gqunube Estuary, 33°06'00.00"S, 28°08'17.99"E; 700- 650 m. USNM 62498 (2 specimen: holotype): Southern margin, 44 km from Port St. Johns / 4 km from Mkweni Estuary, 31°22'59.99"S, 29°53'59.99"E; 410 m.

Imagery data.

USNM 91721 (4 specimens: paratypes): Eastern margin, 46 km from Port Dunford/45 km off Nyoni Estuary, 29°19'12.00"S, 32°00'00.00"E; 366 m. Galathea St. 196 (2 specimens). USNM 87645 (5 specimens): Eastern margin, 146 km from Gouritsmond/152 km off Goukou Estuary, 35°40'12.00"S, 21°58'48.00"E; 424 m.

Description.

Corallum elongated, sub-cylindrical, mostly attached through a slender pedicel, which expands into an encrusting base. Thecal edge diverging at an angle of 7-9°. Coralla rarely straight, most examined specimens bent near base. Calice calicular with thin and fragile calicular margin. Largest specimen examined (SAM_H2841) 6.3 × 6.2 mm in CD, and 38.0 mm in H. Theca fragile; epitheca bear longitudinal ridges corresponding to septa. Spaces between epithecal ridges usually have transverse and fine striations. Corallum light brown and sometimes white.

Septa hexamerally arranged in two cycles according to the formula: S1> S2 (12 septa). S1 extend towards centre of fossa with straight to slightly sinuous axial margin. S2 half the width of S1, also with slightly sinuous axial margin. Lower septal faces bear a row of spines. Fossa deep and narrow.

Distribution.

Regional: Southern to eastern margin of South Africa, off Cape Point extending to Cape Vidal, 80-775 m. Elsewhere: Only known from South Africa (Cairns and Zibrowius 2016).

Remarks.

Flabellum (F.) leptoconus was well described by Cairns and Zibrowius (2016) and examined specimens add no taxonomic information, apart from the row of spines present on the septal faces deep in fossa.