A new deep-water coral species Telestula ridgensis sp. nov (Scleralcyonacea: Sarcodictyonidae) from the seamount of theCentral Indian Ridge Author Periasamy, Rengaiyan 0000-0001-6941-4074 National Centre for Polar and Ocean Research (NCPOR), Ministry of Earth Sciences (MoES), Headland Sada, Vasco-da-Gama, Goa, India- 403804 & periasamy @ ncpor. res. in; https: // orcid. org / 0000 - 0001 - 6941 - 4074 periasamy@ncpor.res.in Author Kurian, Palayil John 0000-0001-9381-8167 National Centre for Polar and Ocean Research (NCPOR), Ministry of Earth Sciences (MoES), Headland Sada, Vasco-da-Gama, Goa, India- 403804 & john @ ncpor. res. in; https: // orcid. org / 0000 - 0001 - 9381 - 8167 john@ncpor.res.in Author Ingole, Baban National Centre for Polar and Ocean Research (NCPOR), Ministry of Earth Sciences (MoES), Headland Sada, Vasco-da-Gama, Goa, India- 403804 text Zootaxa 2023 2023-03-10 5254 2 231 244 http://dx.doi.org/10.11646/zootaxa.5254.2.4 journal article 10.11646/zootaxa.5254.2.4 1175-5326 7727292 AF9325A8-00A5-4D40-B16C-F983A585CF19 Telestula ridgensis sp. nov. Figs 1–8 Type material: holotype : Specimen , NCPOR /HYD-CIR/0048, Seamount of the Central Indian Ridge , Indian Ocean , R / V ‘ MGS Sagar’ cruise MGS–35 (Station MGS-35A-BD21), 24 April 2020 , 23°10′28.92′′ S , 69°32′47.04′′ E , 1917 to 2053 m , Benthic Sledge , Coll. Periasamy R , samples in 90% ethanol . Paratypes : One specimen NCPOR /HYD-CIR/0049 from the same locality as the holotype . Ecological note: The specimen was collected along with two types of carnivorous sponges; three types of deepsea coral, three types of brittle stars, shrimps; and dead gastropod shells from medium-grained basalt rocky bottom with thick Fe-Mn crust. FIGURE 1. The map shows the collection site of Telestula ridgensis sp. nov . in the Central Indian Ridge. The black line indicates the ridge axis. Coloration: The color of colonies ranges from yellowish-brown to dark brown or black; with their ends forming white or cream polyps. Distribution: Telestula ridgensis sp. nov. is known only for its type locality in the seamounts of the Central Indian Ridge system. Etymology: The specific name refers to the type locality of the Indian Ocean Ridge. Gender is feminine. Description Coral colonies are inter-connected with polyps by ribbon - like stolon expanding in irregular patterns on the surface of a dead coral ( Fig. 2A ), and budding of secondary polyps ( Fig. 2C ). The polyps arise from a ribbon - like stolon ( 0.6 mm in width). FIGURE 2 . Telestula ridgensis sp. nov. NCPOR/HYD-CIR/0048 A, preserved colonies on the dead Corallidae coral; B, polyps; C, budding of secondary polyps; D, tentacles. The holotype is about 19.7 mm tall and 0.2 mm in diameter, with eight polyps attached ( Fig. 2D ). Fully retracted polyps are up to 12 mm in height and 1.5 mm in width. Sclerites in the polyp ( Fig. 3A,B,C ) form a thick layer in the calyx wall region, being longitudinally arranged and tightly packed ( Fig. 3D ). The stolon is ribbon-shaped, with sclerites longitudinally arranged along the thin basal stolon ( Fig. 3E ). The sclerites in the tentacles and middle of the neck zone are transversely set ( Fig. 4A, B,C ). Tentacles sclerites are narrow and stellate plates; cross-like forms with slightly tubercular ornamentation; stellate plates (0.19– 0.06 mm long 0.08– 0.02 mm wide); cross-like sclerites ( 0.058 –0.082 mm long 0.047 –0.064 mm wide); smaller crosses, all of them with tubercular ornamentation ( Fig. 5A ). Pharyngeal sclerites are small warty plates ( 0.07–0.13 mm long, 0.010 –0.032 mm wide) ( Fig. 5B ). Neck zone sclerites are short, blunt rods, crosses with tubercular ornamentation; 0.16– 0.07 mm in length, 0.05– 0.01 mm wide; some crosses ( Fig. 6A ). FIGURE 3. Illustration of a Telestula ridgensis sp. nov. NCPOR/HYD-CIR/0048, A-C, polyp indicating the locations and types of sclerites; D, arrangement of sclerites in the calyx wall region; E, ribbon-like stolon. FIGURE 4 . Telestula ridgensis sp. nov . NCPOR/HYD-CIR/0048, arrangement of sclerites in the neck zone. A, is the neck zone; B, is towards tentacles, after removal of the soft tissue; C, the arrangement of the sclerites in the tentacle after removal of the soft tissue. FIGURE 5 . Sclerites of Telestula ridgensis sp. nov. NCPOR/HYD-CIR/0048 A, tentacles with stellate plates, blunt rods with slightly tubercular ornamentation; B, pharyngeal with blunt rods. I ntrusion sclerites are irregular-shaped, branched rods with tubercular ornamentation ( 0.14–0.52 mm long, 0.03–0.11 mm wide) ( Fig. 6B ). FIGURE 6 . Sclerites of Telestula ridgensis sp. nov . NCPOR/HYD-CIR/0048 A, irregularly shaped with dense tubercular ornamentation in a neck zone; B, intrusion tissue with branched forms with dense tubercular ornamentation Calyx wall sclerites are irregular-shaped; crosses with dense tubercular ornamentation (0.45– 0.15 mm long 0.37– 0.06 mm wide); frequently with cross-like prominences ( Fig.7A ). Stolon sclerites are smooth to slightly warty plate,crosses; irregular-shaped with slightly tubercular ornamentation (0.40– 0.19 mm long 0.42– 0.02 mm wide); less cross-shaped forms ( 0.12– 0.25 mm long) ( Fig. 7B ). Remarks. The sclerome found in Telestula ridgensis sp. nov. is unique among the north-eastern Atlantic congeners having longitudinal rows of small warty rods and cross-like forms that extend from the distal end of the calyx towards the base of the tentacles. The sclerites of the new species from the neck zone, intrusion tissue, calyx wall, and ribbon-like stolon are notably different among the genus Telestula with an evident abundance of warty, irregular, and cylinder-like forms of small flattened ovals. Telestula ridgensis sp. nov. is morphologically closely related to Telestula septentrionalis , T . cf. batoni , and T . cf. spiculicula . According to Tixier-Durivault (1964) species, T. tubaria has eight chevrons of small sclerites in the neck region and eight longitudinal ridges of sclerites in a calyx wall. However, T. versluysi has densely tuberculate rounded spindles from the calyx wall and irregular spindles from the stolon ( Weinberg 1990 ). T. mosaica has some arrowhead-like sclerites. The sclerites of T . kuekenthali have loose polyps, plump, coarsely tuberculate spindles from the calyx wall, irregular spindles, and cross-shaped sclerites from the top of the polyp ( Weinberg 1990 ). Telestula stocki has plates on top of tentacles, sparse long spindles, warty spindles with complex tubercles, rods from stolon, and plump ( Weinberg 1990 ).