Truncatoflabellum inconstans (von Marenzeller, 1904a)

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 inconstans (von Marenzeller, 1904a)

Fig. 12M, N

Flabellum inconstans von Marenzeller, 1904a: 277-280, pl. 27, figs 11 A-L. - Boshoff 1981: 34.

Flabellum harmeri . - Boshoff 1981: 35.

Truncatoflabellum inconstans . - Cairns 1989b: 61. - Cairns and Keller 1993: 220. - Cairns 2016: 34, fig. 9D.

Type locality.

Off St. Francis Bay, South Africa (SS ' Valdivia ' stn. 100: 34°08'09"S, 24°59'30"E); 100 m (von Marenzeller 1904a).

Type material.

The syntype are deposited at the ZMB (GBIF 2020).

Material examined.

ORI_DIIb2 (1 specimen): Locality data unknown. ORI_ DIIb3 (in part: 1 specimen): Locality data unknown, 27 m. SAMC-A072990 (1 specimen), SAMC-A072991 (3 specimens): Locality data unknown. SAMC-A090103 (1 specimen): Southern margin, 15 km from Arniston / 21 km from De Mond-Heuningnes Estuary, 34°46'59.99"S, 20°19'00.00"E; 80 m. SAM_H1241 (in part: 1 specimen): Southern margin, 2 km from Kei Mouth / 27 km off Groot Berg Estuary, 32°40'33.99"S, 28°22'50.99"E; 66 m. SAM_H1381 (1 specimen): Eastern margin, 2 km from Durban / 8 km off Umgeni Estuary, 29°51'59.99"S, 31°00'00.00"E; 101 m. SAM_H1382 (2 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. SAM_H1386 (1 specimen): Southern margin, 28 km from Gonubie / 27 km off Buffalo Estuary, 33°09'29.99"S, 28°03'06.00"E; 86 m. SAM_H1392 (2 specimens): Southern margin, 6 km from Kenton On Sea / 5 km off Boknes Estuary, 33°43'07.59"S, 26°37'37.95"E; 90 m. SAM_H1417 (1 specimen): Southern margin, 29 km from Kenton On Sea /off Boesmans Estuary, 33°53'39.99"S, 26°51'00.00"E; 121 m. SAM_H1425 (1 specimen): Southern margin, 7 km from East London / 5 km off Buffalo Estuary , 33°02'59.99"S, 27°57'00.00"E; depth unknown. SAM_H1434 (4 specimens): Locality data unknown. SAM_H1435 (1 specimen): Southern margin, 6 km from Kidds Beach / 5 km off Ncera Estuary, 33°11'59.99"S, 27°40'59.99"E; 79 m. SAM_H1444 (2 specimens): Southern margin, 14 km from Cape Padrone / 26 km off Boknes Estuary, 33°46'00.00"S, 26°19'00.00"E; 104 m. SAM_H1446 (1 specimen): Southern margin, 6 km from Kidds Beach / 5 km off Ncera Estuary, 33°11'59.99"S, 27°40'59.99"E; 79 m. SAM_H1470 (2 specimens): Eastern margin, 27 km from Mtunzini / 25 km off Matigulu Estuary, 29°10'36.00"S, 31°51'00.00"E; 115 m. SAM_H1511 (2 specimens): Southern margin, 25 km from Port Elizabeth / 23 km off Bakens River Estuary, 33°49'36.36"S, 25°47'42.94"E; 49- 183 m. SAM_H3071 (34 specimens): Southern margin, 6 km from Kenton On Sea / 5 km off Boknes Estuary, 33°43'07.59"S, 26°37'37.95"E; 90 m. SAM_H3130 (1 specimen): Southern margin, 46 km from Port Alfred / 12 km off Mgwalana Estuary, 33°29'24.00"S, 27°21'11.99"E; 80 m. SAM_H3155 (1 specimen): Southern margin, 47 km from Port Alfred / 14 km off Mgwalana Estuary, 33°30'18.00"S, 27°22'05.99"E; 80 m. DEFF_NANSEN-INV 19 (2 specimens): Eastern margin, 20 km from Durban / 19 km off Beachwood Mangroves; 29°52'56.39"S, 31°12'15.59"E; 218 m.

Imagery data.

BMNH 1939.7.20.816-833 (in part: 1 specimen): Southern margin, 7 km from East London/5 km off Buffalo Estuary, 33°02'59.99"S, 27°57'00.00"E; 62 m. BMNH-1950.1.10.97-102 (in part: 1 specimen): Locality data unknown. DTE 100 (syntype: 1 specimen): Southern margin, 12 km from Jeffreys Bay/21 km off Gamtoos Estuary, 34°08'53.99"S, 24°59'17.99"E; 100 m. Mortensen St 30 (2 specimens): Eastern margin, off Durban; 94 m. Mortensen St 31 (14 specimens): Eastern margin, off Durban; 128 m.

Description.

Corallum (anthocyathus) large, robust, and having a small open base. Calice elliptical to sub-cylindrical (GCD:LCD = 1.47-2.60), with a thin and smooth calicular margin. Basal scar 5.3-6.6 × 3.4-4.0 mm in diameter, with 24 complete septa originating from scar. Largest anthocyathus examined (SAM_H1386) 25.6 × 18.1 mm in CD and 37.4 mm in H. Theca bears fine longitudinal striae, and chevron-shaped growth lines. C1-3 distinct and extend from calicular margin to base. Thecal edge smooth, rounded, or acute. Thecal edge diverges in an angle between 45 and 55°, and thecal faces between 20 and 25°. Corallum white.

Septa hexamerally arranged in six cycles, last being incomplete, according to the formula: S1-3> S4> S5> S6 (102 septa). However, smaller coralla (<25 mm GCD) display ≤ 78 septa. S1-3 greater in width than S4, and having vertical, slightly sinuous, and thickened axial margins. S4 ~ ½ the width of S1-3, and bear sinuous axial margin, which sometimes appear to be dentate. S51/3 the width of S4, and have dentate axial margin. However, if S6 is absent, S5 rudimentary. S6 rudimentary. Septal faces covered with granules obliquely aligned in rows along septal margin. Fossa deep containing a rudimentary columella formed by S1-3 lower axial margin.

Distribution.

Regional: Southern to eastern margin of South Africa, off Jeffreys Bay extending towards Durban; 29-183 m. Elsewhere: Only known from South Africa.

Remarks.

The South African endemic Truncatoflabellum inconstans differs from the other South African congeners by lacking thecal spines, in thecal edge and thecal face inclinations, GCD:LCD ratio, H:GCD ratio, number of septa, and distinction of ribbed C1-3 ( Cairns 2016). However, T. inconstans may be mistaken with T. stabile (von Marenzeller, 1904a); T. inconstans differs in having a thecal edge angle inclination range of 40-50° (as opposed to the 60-90° range of T. stabile ), and a H:GCD between 1.0-1.5 (compare with 0.7-1.1 of T. stabile ) (key in Cairns 2016: 9).

Figures

Figure 12. A, B Javania insignis (SAMC _ A 090116, off Port Dunford, 85 m) A calicular view B lateral view C, D Placotrochides scaphula (USNM 91772, off Scottburgh, 1360 m) C calicular view D calicular view E, H Rhizotrochus typus E, F (SAMC _ A 090094, off Coffee Bay, 160 m) E calicular view F lateral view G, H (SCD 39 B, off Coffee Bay, 160 m) G calicular view H lateral view I, J Truncatoflabellum formosum (SAM _ H 1389, off Shaka's Rock, 183 m) I calicular view J lateral view K, L Truncatoflabellum gardineri (SAM _ H 3847, off Shaka's Rock, 138 m) K calicular view L lateral view M, N Truncatoflabellum inconstans (SAM _ H 1241, off Kei Mouth, 66 m) M calicular view N lateral view O, P Truncatoflabellum multispinosum (SAMC _ A 087450, locality data unknown) O calicular view P lateral view. Scale bars: 10 mm.