Two new species of the genus Chironephthya (Octocorallia, Alcyonacea, Nidaliidae Siphonogorgiinae) from the Gulf of Thailand Imahara, Yukimitsu Chavanich, Suchana Viyakarn, Voranop Kushida, Yuka Reimer, James D. Fujita, Toshihiko Zootaxa 2020 2020-05-25 4780 2 324 340 866FR Imahara & Chavanich & Viyakarn & Kushida & Reimer & Fujita, 2020 Imahara & Chavanich & Viyakarn & Kushida & Reimer & Fujita 2020 [151,497,978,1005] Anthozoa Nidaliidae Chironephthya Animalia Alcyonacea 4 328 Cnidaria species sirindhornae sp. nov.  ( Figs. 2–7)  urn:lsid:zoobank.org:act: 4FD6B1EF-8175-4326-BDB3-F2CD9DAD3A96 Japanese name: Hime-kudayagi     Holotype.NSMT-Co 1703, at  19 mdepth, Hin Lom Fang, off Pattaya, Chonburi Province, Thailand( 12°48.37'N, 100°42.35'E), on  13 October 2013. GenBank Accession No.  MT424941(mtMutS),  MT414716(COI),  MT419962(28SrDNA).   Description. Colony form: Colony, 34 mmhigh, consisting of nine polyparia arising from a thin membranous common base, spreading over the dead holaxonian axis of 55 mmlong and 3–13 mmwide, soft and somewhat translucent in life ( Fig. 2) but stiff and opaque in ethanol ( Fig. 3). Inside the common base, there are several canals, 0.2–0.6 mmin diameter, penetrated. Lower portion of each polyparium is a short sterile stem, 3–14 mmlong and 2.0 x 2.5–5.2 x 6.5 mmin diameter in the proximal portion. Polyparia 7–47 mmhigh (including lower stem), sparsely branched in one plane. Terminal branches short, rod-like when alive, but deformed into club-shape with distal swollen portion with slightly withered polyparia after fixation, 2–4.6 mmlong and 1.5 x 2.0– 4.8 x 5.2 mmin diameter at the most swollen portion. The interior of stem, there are four to six thick canals leading to apical polyps and other two to three thin canals. Canal walls are thin, soft and limp.  Polyps: Polyps monomorphic, distributed at long intervals on the upper stem ( Fig. 4B), arranged sparsely, somewhat in a spiral formation on the lateral sides of branches ( Fig. 4A), and crowded 4–6 innumber at the distal portion of each terminal branch ( Fig. 4D, E). Calyces, in two types, cup-shaped ( Fig. 4E) at distal portion of terminal branches, and shelf-like ( Fig. 4A, 5A, B) on lateral sides of branches and stem. Both typesof calyces supported by 2–3 teeth formed by 5–7 large spindles of < 2 mmlong ( Fig. 7A 1) on the outer surface, and having small slender spindles or needles of < 0.2 mmlong ( Fig. 7A 2) embedded in the inner surface. Anthocodiae ( Fig. 5C–D), < 0.8 mmhigh and < 1 mmwide, armed by eight points and a crown. Each point consists of one pair of large spindles of < 0.46 mmand 2–3 pairs of small spindles of < 0.23 mmlong ( Fig. 6B). Crown bearing 6–8 rows of horizontally-disposed curved spindles < 0.43 mmlong ( Fig. 6D). Between two adjacent points, intermediate sclerites of 1–2 pairs of rods, < 0.18 mmlong ( Fig. 6C). Anthocodial formula: 1P+(2–3)p+(6–8)Cr+(1–2)M. The axis of each tentacle has many small rods, reaching 0.11 mmin length, ( Fig. 6A) arranged perpendicular to the axis or in a chevron toward the distal end. Pinnules completely free from sclerites. Pharynx has several small spiny spindles reaching 0.05 mmin length ( Fig. 6E).   FIGURE 2.Live colony of  Chironephthya sirindhornae  sp. nov.(NSMT-Co 1703).   FIGURE 3.Preserved specimen of  Chironephthya sirindhornae  sp. nov.(NSMT-Co 1703). A: whole colony; B: view from opposite side of A. cb: common base; st: stem.  Sclerites of coenenchyme: Surface layer of branches covered tightly with vertically aligned large spindles of < 2.68 mmlong with many complex warts ( Fig. 7B 1), and slender spindles of < 0.74 mmlong with a few complex warts and blunt ends ( Fig. 7B 2above), and small curved spindles of < 0.18 mmlong with a few conical warts ( Fig. 7B 2below). Interior of branches containing a few needles of < 0.24 mmlong with a few large simple warts ( Fig. 7C). Surface layer of stem and common base covered tightly with large spindles of < 2.78 mmlong with many complex warts ( Fig. 7D 1) and slender spindles of < 0.66 mmlong with a few complex warts ( Fig. 7D 2). Interior of stem and common base containing a few spindles of < 0.49 mmlong with a few compound warts ( Fig. 7E 1), and a few needles of < 0.28 mmlong with a few conical warts ( Fig. 7E 2).   FIGURE 4.Preserved specimen of  Chironephthya sirindhornae  sp. nov.(NSMT-Co 1703). Arrangement of polyps. A: lateral side of a terminal branch; B: lower of stem; C: lower portion of colony; D: distal portion of a terminal branch; E: lateral side of distal portion of a terminal branch. cb: common base. Scales: A–C: 5 mm; D, E: 1 mm.   FIGURE 5.Preserved specimen of  Chironephthya sirindhornae  sp. nov.(NSMT-Co 1703). A: solitary polyp on the lateral side of branch, showing the shape of calyx; B: arrangement of spindles on calyx of lateral side of branches; C–D: lateral view of anthocodiae, showing arrangement of sclerites; E: tentacles, showing arrangement of sclerites; F: cross section of stem, showing arrangement of canals. cl: calyx; cn: canal; cr: crown; pn: point; tn: tentacle. Scales: A–D: 1 mm; E: 0.1 mm; F: 5 mm.  Color: Colony translucent pale pink, with yellow point sclerites and red crown sclerites in life. The color of colony changes to opaque dull pale pink in ethanol.   Etymology.The specific epithet is named in honor of Her Royal Highness Princess Maha Chakri Sirindhorn of Thailand, who has initiated and implemented the Plant Genetic Conservation Project for maintenance and conservation of biodiversity both on land and in the ocean.   Remarks.This new species differs from other species of  Chironephthyain that it has multiple stems arising from a common base, and lacks large spindles in the interior of the coenenchyme. This species is distinguished clearly from its congener  C. macrospiculata Thomson & Henderson, 1906by the size of coenenchyme cortical spindles (< 8.3 mmlong) and by the structure of anthocodial formula (2P+2p+3Cr). The appearance of the living colony of this species is very similar to that of  Scleronephthya, but the presence of the calyx existing at the proximal portion of polyps and vertically-aligned spindles on the cortex of the coenenchyme enables distinguishing between them underwater, if carefully observed. 2625374302 2013-10-13 MT GenBank Accession No. Thailand 19 12.806167 Hin Lom Fang 13 100.70583 Pattaya 4 328 1 Chon Buri holotype