Truncatoflabellum pusillum Cairns, 1989a

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

Truncatoflabellum pusillum Cairns, 1989a

Fig. 13A, B

Truncatoflabellum pusillum Cairns, 1989a: 71-72, pl. 37, figs A-E. - Cairns and Keller 1993: 265, pl. 11, fig. E. - Cairns and Zibrowius 1997: 170. - Cairns 1999a: 120, figs 19G, H. - Cairns et al. 1999: 32. -Randall 2003: 136. - Cairns 2009: 19. - Cairns 2016: 16, fig. 3B. - Kitahara and Cairns 2021: 256-257, 259, figs 134, 135A-L.

Type locality.

Sibuyana Sea, Philippines (RV ‘Albatross’ stn. 5178: 12°43'N, 122°06'15"E); 143 m ( Cairns 1989a).

Type material.

Types are at the NMNH ( Cairns1989a).

Material examined.

SAMC_A073189 (1 specimen): Eastern margin, 9 km from Shaka’s Rock / 12 km off Mhlali Estuary, 29°32'12.11"S, 31°19'36.11"E; 50 m. SAMC_A073200 (1 specimen): Eastern margin, 19 km from Shaka’s Rock / 20 km off Mhlali Estuary, 29°33'11.88"S, 31°25'23.88"E; 60- 64 m. SAM_H2838 (57 specimens): Eastern margin, 19 km from Shaka’s Rock / 3 km off Mdloti Estuary, 29°38'59.99"S, 31°07'59.99"E; 71- 73 m. SAM_H2839 (24 specimens): Southern margin, 48 km from Cape Padrone / 47 km off Bakens River Estuary, 34°04'59.99"S, 26°05'59.99"E; 37 m.

Description.

Corallum small (GCD <13.0 mm). Calice may be short or long, but always highly compressed (GCD:LCD = 1.1-1.3). Calicular margin thin and slightly serrated. Basal scar 4.0 × 2.8 mm in diameter, with 24 septa originating from scar. Largest anthocyathus examined (SAM_H2839) 15.2 × 7.6 mm in CD, and 13.4 mm in H. Theca porcelaneous, bearing thin transverse chevron-shaped lines. Thecal spines sometimes present (≤ 3), usually of various size and shape, but consistently facing downwards. Thecal faces diverge in an angle between 18 and 20°, and thecal edge between 14 and 18°. Corallum white, with faint greenish brown stripes on theca.

Septa hexamerally arranged in five cycles, last being incomplete, according to the formula: S1 ≥ S2> S3> S4> S5 (≤ 60 septa). S1 ca. the same size or only slightly larger than S2. S1-2 axial margins vertical and sinuous. S3 ¾ the width of S1-2 and bear sinuous to dentate axial margin. S4 small, ~ 1/3 the width of S3, and have dentate axial margin. S5 rudimentary. Septal faces covered with granules. Fossa of moderate depth, containing a rudimentary columella formed by the fusion of S1-3 lower axial margins.

Distribution.

Regional: Southern and eastern margin of South Africa, off Cape Padrone extending towards Shaka’s Rock; 37-73 m. Elsewhere: Philippines ( Cairns 1989a; Cairns and Zibrowius 1997); Indonesia ( Cairns and Zibrowius 1997); New Caledonia ( Cairns 2016; Kitahara and Cairns 2021); Mozambique ( Cairns and Keller 1993); 85-460 m.

Remarks.

Although Truncatoflabellum pusillum was previously known from the southwest Indian Ocean, the new records reported herein represent a further southwards range extension, from Mozambique into South Africa. The South African specimens vary from the existing descriptions ( Cairns 1989a; Cairns and Zibrowius 1997; Cairns 1999a) in having ≤ 60 septa instead of 48, a larger CD (12.0 mm as compare with 8.0 mm), and a basal scar of 4 × 3 mm (rather than 2.4-3.2 × 1.7-1.8 mm). The South African T. pusillum resembles T. dens in septal symmetry and CD size, but differs in having thecal spines (rather than crests), and thecal edge diverging in an angle of 14-18° instead of a bimodal edge angle.

Figures

Figure 13. A, B Truncatoflabellum pusillum (SAM _ H 2839, off Cape Padrone, 37 m) A calicular view B lateral view C, D Truncatoflabellum zuluense (SAMC _ A 090096, off Cape Vidal, 85 m) C calicular view D lateral view E, F Truncatoflabellum sp (SAMC _ A 073161, off Port St. Johns, 140 - 145 m) E calicular view F lateral view G, H Fungiacyathus (Bathyactis) hydra (USNM 86869, off Alexandra Bay, 882 m) G calicular view H basal view I, L Fungiacyathus (Bathyactis) sibogae (SAM _ H 1697, off Mgobezeleni Estuary, 1050 m) I calicular view J basal view K calicular view L basal view M, N Fungiacyathus (Fungiacyathus) sp. (SAM _ H 1431, off Durban, 99 m) M calicular view N basal view O, P Guynia annulata (USNM 77201, off Port St. Johns, 138 m) O calicular view P lateral view. Scale bars: 10 mm (A-N); 2 mm (O, P).