Cyathotrochus pileus (Alcock, 1902)

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

Cyathotrochus pileus (Alcock, 1902)

Fig. 15A, B

Endopachys australiae Tenison-Woods, 1878: 333, pl. 6, fig. 1A-C.

Tropidocyathus bougainvillea Milne-Edwards & Haime, 1857: 57.

Trochocyathus pileus Alcock, 1902a: 96-97. - Alcock 1902c: 15-16, pl. 2, figs 11, 11A. -Faustino 1927: 8, 34, 39, 81. -Gardiner and Waugh 1938: 187. - Yabe and Eguchi 1942b: 106, 123.

Tropidocyathus pileus . - Cairns 1989a: 34-35, pl. 17, figs A-H. -Cairns 1994: 68, pl. 29, figs D, E. - Cairns 1995: 91, pl. 28, figs A-C. - Cairns and Zibrowius 1997: 147-148, fig. 19H, I.

Cyathotrochus pileus . - Cairns 1997: 16, pl. 1, figs F-G, pl. 4, fig. F. - Cairns 1998: 392.- Cairns 1999: 110-111. - Cairns et al. 1999: 40. -Cairns 2004a: 292, figs 6D, E. - Kitahara et al. 2010b: 9. - Kitahara and Cairns 2021: 95-96, 98, figs 36H, 37, 38A-C.

Type locality.

Sulu Archipelago, Philippines (HMS ‘Siboga’ stn. 95: 5°43'00"N, 119°40'00"E); 522 m (Cairns 1994).

Type material.

Four syntypes are deposited at the ZMA (Cairns 1994).

Material examined.

SAMC_A073181 (2 specimens): Eastern margin, 11 km from Port St. Johns / 10 km off Bulolo Estuary, 31°43'54.12"S, 29°32'12.11"E; 190 m. SAMC_A087424 (1 specimen): Eastern margin, 19 km from Durban / 18 km off Beachwood Mangroves, 29°53'24.00"S, 31°11'12.11"E; 270 m.

Description.

Corallum cuneiform, laterally compressed, with a rounded base. Thecal edge crests absent. Calice elliptical (GCD:LCD = 1.7-1.9), calicular margin lanceted. Largest specimen examined (SAMC_A073181) 21.2 × 12.3 mm in CD, and 21.5 mm in H. Costae ridged, serrated, highly granular, and equal in width. Intercostal striae narrow, deep, and extend to base. Corallum predominantly pale cream, but freshly collected specimens pale orange with white septa and calicular margin.

Septa hexamerally arranged in five incomplete cycles according to the formula: S1 ≥ S2 > S4 > S3 or S1 ≥ S2 > S3 > S5 > S4. S1 highly exsert and each bearing a small palus. S2 slightly less exsert, and slightly smaller or equal in size to S1. P2 similar to P1 but rising higher than it in fossa. In half-systems without S5, S3 smaller and less exsert than S2 and bear the widest pali. S4 dimorphic in development: those adjacent to S1 are wider than those adjacent to S2. S4 fuses to S1 and S2 at calicular margin forming triangular apexes. In half-systems with S5, S3 small and bear a wide palus. S4 adjacent to S2 slightly wider than S3 and also bear a wide palus. S4 adjacent to S1 lack pali. S5 dimorphic in development: those adjacent S1 wider but as exsert as ones neighbouring S2. All axial edge of septa and pali slightly sinuous, with faces being uniformly covered by pointed and sharp granules. Columella papillose and aligned with GCD, but sometimes difficult to view due to the highly compressed corallum.

Distribution.

Regional: Eastern margin of South Africa, off Port St. Johns extending towards Durban; 190-270 m. Elsewhere: Tanzania (Gardiner and Waugh 1938); Japan; South China Sea (Cairns 1994); Philippines; Indonesia ( Cairns and Zibrowius 1997); Australia ( Cairns 1998); Vanuatu ( Cairns 1999a); New Caledonia ( Kitahara and Cairns 2021); 123-1110 m.

Remarks.

Although two authors have reported Cyathotrochus pileus before (Alcock, 1902a), their priority is discounted based on varying nomenclature reasons. Endopachys australiae Tenison-Woods 1878 account of species was not used in the literature subsequent to its original description. Whilst Tropidocyathus bougainvillea Milne-Edwards & Haime, 1857 type material is untraceable and the authors did not illustrate their specimens ( Cairns 1989a). Thus, according to article 23.9.1 of the ICZN (1999), Endopachys australiae is considered to be a nomen oblitum and C. pileus to be a nomen protectum. There are two extant species belonging to Cyathotrochus ( C. pileus and C. nascornatus (Gardiner and Waugh 1938)), which may be distinguished based on the irregularity of coralla (as a result of asexual reproduction) taken by C. nascornatus ( Cairns 1989a). Nonetheless, examined specimens represent new records of Cyathotrochus pileus from South Africa and, therefore, extend its known distribution from south of Tanzania. Among the Turbinoliidae of the region, C. pileus resembles Tropidocyathus lessonii , but can be distinguished by the lack of thecal edge crest, ridged costae, and triangular apexes at the calicular margin.

Figures

Figure 15. A, B Cyathotrochus pileus (SAMC _ A 087424, off Durban, 270 m) A calicular view B lateral view C, D Deltocyathoides orientalis (BIVa 2, locality unknown, 80) C calicular view D basal view E, F Deltocyathoides sentus (USNM 91551, off Shaka's Rock, 300 m) G, H Sphenotrochus (Eusthenotrochus) gilchristi (SAMC _ A 090086, off Cape Point, 24 m) G calicular view H lateral view I, J Sphenotrochus (Sphenotrochus) aurantiacus (SAM _ H 1416, off the Agulhas, 366 m) I calicular view J lateral view K, L Sphenotrochus (Sphenotrochus) evexicostatus (SAMC _ A 090085, locality data unknown, 43 m) K calicular view L lateral view M, N Sphenotrochus (Sphenotrochus) imbricaticostatus (USNM 91715 _ Holotype, off Kosi-Kumpungwini (Sifungwe) Estuary, 44 m) K calicular view L lateral view O, P Tropidocyathus lessonii (SAMC _ A 073218, off Kosi Bay Estuary, 74 m) O calicular view P lateral view. Scale bars: 10 mm (A-H, J-M, O-P); 2 mm (I, N).