Chironephthya sirindhornae Imahara & Chavanich & Viyakarn & Kushida & Reimer & Fujita 2020, sp. nov.
Creators: name: Imahara, Yukimitsu
name: Chavanich, Suchana
name: Viyakarn, Voranop
name: Kushida, Yuka
name: Reimer, James D.
name: Fujita, Toshihiko
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Cnidaria
Anthozoa
Alcyonacea
Nidaliidae
Chironephthya
Chironephthya sirindhornae

description: Chironephthya 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 m depth, Hin Lom Fang, off Pattaya, Chonburi Province, Thailand (12°48.37'N, 100°42.35'E), on 13 October 2013. GenBank Accession No. MT 424941 (mtMutS), MT 414716 (COI), MT 419962 (28SrDNA).
Description. Colony form: Colony, 34 mm high, consisting of nine polyparia arising from a thin membranous common base, spreading over the dead holaxonian axis of 55 mm long and 3–13 mm wide, 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 mm in diameter, penetrated. Lower portion of each polyparium is a short sterile stem, 3–14 mm long and 2.0 x 2.5–5.2 x 6.5 mm in diameter in the proximal portion. Polyparia 7–47 mm high (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 mm long and 1.5 x 2.0– 4.8 x 5.2 mm in 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 in number 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 types of calyces supported by 2–3 teeth formed by 5–7 large spindles of <2 mm long (Fig. 7A 1) on the outer surface, and having small slender spindles or needles of <0.2 mm long (Fig. 7A 2) embedded in the inner surface. Anthocodiae (Fig. 5 C–D), <0.8 mm high and <1 mm wide, armed by eight points and a crown. Each point consists of one pair of large spindles of <0.46 mm and 2–3 pairs of small spindles of <0.23 mm long (Fig. 6B). Crown bearing 6–8 rows of horizontally-disposed curved spindles <0.43 mm long (Fig. 6D). Between two adjacent points, intermediate sclerites of 1–2 pairs of rods, <0.18 mm long (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 mm in 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 mm in length (Fig. 6E).
Sclerites of coenenchyme: Surface layer of branches covered tightly with vertically aligned large spindles of <2.68 mm long with many complex warts (Fig. 7B 1), and slender spindles of <0.74 mm long with a few complex warts and blunt ends (Fig. 7B 2 above), and small curved spindles of <0.18 mm long with a few conical warts (Fig. 7B 2 below). Interior of branches containing a few needles of <0.24 mm long with a few large simple warts (Fig. 7C). Surface layer of stem and common base covered tightly with large spindles of <2.78 mm long with many complex warts (Fig. 7D 1) and slender spindles of <0.66 mm long with a few complex warts (Fig. 7D 2). Interior of stem and common base containing a few spindles of <0.49 mm long with a few compound warts (Fig. 7E 1), and a few needles of <0.28 mm long with a few conical warts (Fig. 7E 2).
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 Chironephthya in 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, 1906 by the size of coenenchyme cortical spindles (<8.3 mm long) 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.
description: Published as part of Imahara, Yukimitsu, Chavanich, Suchana, Viyakarn, Voranop, Kushida, Yuka, Reimer, James D. & Fujita, Toshihiko, 2020, Two new species of the genus Chironephthya (Octocorallia, Alcyonacea, Nidaliidae Siphonogorgiinae) from the Gulf of Thailand, pp. 324-340 in Zootaxa 4780 (2) on pages 328-332, DOI: 10.11646/zootaxa.4780.2.6, http://zenodo.org/record/3842504