Caryophyllia (Caryophyllia) ephyala Alcock, 1891

3. Caryophyllia (Caryophyllia) ephyala Alcock, 1891 View in CoL

( Figs. 3A–C View FIGURE 3 )

Caryophyllia ephyala Alcock View in CoL in Wood-Mason & Alcock, 1891: 6–2.— Alcock 1898: 13–14, pl. 1, fig. 4, 4A.— Gardiner 1904: 117–118.— Yabe & Eguchi 1932: 388–389.— Cairns & Keller 1993: 219.— Filander et al. 2021: 18–19 View Cited Treatment , fig. 1O,P.

Material examined: One specimen ( NCPOR/HYD-SWIR/0028 ), Southwest Indian Ridge system, R/V MGS Sagar, stn. MGS25_DRG12, 26° 49' 47" S; 67° 40' 46" E, 1641 m, 10 th April 2019 GoogleMaps .

Description: Corallum ceratoid, attached, tapering to a slightly curved and slender pedicel. Calice slightly elliptical in shape with a lancet-shaped calicular edge. Hexamerally arranged septa in four complete cycles (formula: S1≥S2>S3>S4 - 48 septa). S1 equal to or slightly higher, wide and exsert than S2 ( Fig. 3A View FIGURE 3 ); those of third cycle larger and a little more exsert than S4, with a sinuous axial margin bearing a large sinuous pali. Axial edge of S1 somewhat sinuous. S3 less exsert than S1–S2; S4 joins S1-2 and creates a lanceted calicular marginal. Columella deep-seated. All septa and pali covered in granules. Corallum white with faint brownish-pink tinge near calicular margin ( Figs. 3A–C View FIGURE 3 ).

Remarks: Caryophyllia (C.) ephyala belongs to the largest morphological group within the genus Caryophyllia ( Cairns et al. 2005) , characterized by septa hexamerally arranged in four complete cycles. However, it is notable that the septa of the SWIR specimen exhibit a broader and more lanceted calicular margin compared to those described by Alcock (1891), Gardiner (1904), and Filander et al. (2021).

Substrate type: The specimen collected from medium-grained basalt in the SWIR ridge system indicates a habitat that supports benthic fauna, which colonize rocky surfaces. These organisms serve as primary colonizers in harsh deep-sea environments, playing crucial roles in the ecosystem dynamics of the ocean floor.

Distribution: Off the western margin of the Andaman Sea, Bay of Bengal, India (HMS ‘ Investigator’ stn. 56) at a depth 439– 402 m ( Alcock 1891); Western and eastern margin of South Africa ( Gardiner 1904), 146–567 m; Japan ( Yabe & Eguchi 1932), 146–1289 m ( Cairns & Keller 1993). C. (C.) ephyala have recently been identified in the Brak Estuary of South Africa at 440 m ( Filander et al. 2021). The examined specimen of C. (C.) ephyala expands the known distribution to the seamounts of the SWIR at a deeper region of 1641 m.