Crypthelia Milne Edwards & Haime, 1849

1. Genus Crypthelia Milne Edwards & Haime, 1849 View in CoL

( Figs 2A–E View FIGURE 2 )

Material examined: One colony ( NCPOR/HYD-CIR/0044 ), Central Indian Ridge : R/V MGS Sagar, stn. MGS35A_ BD9, 23° 10' 01'' S, 69° 31' 49'' E, 2103 m, 20.04.2020 GoogleMaps .

Description: Small colony, fragile, flabellate, 18 mm high and 13 mm wide; branch base 1–1.2 mm diameter; distal branches about 0.37–0.4 mm in diameter. Dichotomous branching support cyclosystems; one branch of dichotomy usually developed as a small nub; distal branches create sympodial pattern of budding; white coenosteum consists of parallel, convex cords, a width of cords ranged from 52–100 µm with slight grooves. Round to slightly elliptical cyclosystems 2.5– 1.5 mm in diameter. Cyclosystems present on anterior side and raised somewhat on top of branch ~ 0.5 mm; flared predicles; 12–19 dactylopores per cyclosystem; dactylotomes 95–105 µm wide; broaden midway to base of gastropore; triangular pseudosepta up to 0.2 mm wide at external edge of cyclosystem. Every pseudoseptum tapers to apex to about 0.03 mm width. Narrow inner edges of pseudosepta in front of gastropore straight and vertical with somewhat concave upper faces ( Fig. 2B View FIGURE 2 ).

Remarks: The specimen from the CIR resembles Crypthelia fragilis Cairns, 1983 due to its round cyclosystems and triangular pseudosepta with concave upper edges. Additionally, the lid may be present as a narrow concave tongue. C. fragilis has previously been documented only in the Subantarctic region, at depths ranging from 952 to 2329 m. However, the identification of the CIR specimen remains inconclusive due to the absence of male or female ampullae.

Substrate type: The specimen was collected from the medium-grained basalt in the CIR ridge system. The basalt substrate provides a habitat for benthic fauna, which can colonize these rocky surfaces.As primary colonizers in harsh environments, these organisms often play important roles in the deep-sea ecosystem.

Distribution: The genus Crypthelia , with 47 recognized species, is distributed across all three major ocean basins ( Schuchert 2024).