Hana hanataba, Lau, Yee Wah, Stokvis, Frank Robert, Ofwegen, Leendert Pieter van & Reimer, James Davis, 2018

Lau, Yee Wah, Stokvis, Frank Robert, Ofwegen, Leendert Pieter van & Reimer, James Davis, 2018, Stolonifera from shallow waters in the north-western Pacific: a description of a new genus and two new species within the Arulidae (Anthozoa, Octocorallia), ZooKeys 790, pp. 1-19 : 5-7

Hana hanataba sp. n. Figures 2c, 4

Material examined.

Holotype: ROR171225-01, Blue Corner, Ngemelis Island, Palau (7°8.400'N, 134°13.200'E), 23 m depth, coll. YW Lau, 25 July 2017 (MH845550; MH844386). Paratype 1: ROR171226-03, Peleliu PICRC monitoring site, Peleliu, Palau (7°0.400'N, 134°13.060'E), 28 m depth, coll. GY Soong, 26 December 2017 (MH845551; MH845543; MH844387). Paratype 2: DXS180420-1-01, North spur & grooves, Dongsha Atoll, Taiwan (20°46.291'N, 116°46.057'E), 7 m depth, coll. YW Lau, 20 April 2018 (MH845548). Paratype 3: DSX180424-3-15, North, Dongsha Atoll, Taiwan (20°46.677'N, 116°50.090'E), 8 m depth, coll. JD Reimer, 24 April 2018 (MH845549; MH845542; MH844385).

Description.

The colony consists of small polyps (~30) growing on rock. Polyps are spaced apart irregularly (0.5-2.5 mm), connected by stolons that are 0.5 mm in diameter and flat thin ribbon-like in cross-section. Polyps have anthocodia retracted into calyces of 2.5-3.0 mm tall and up to 1.0 mm diameter at the widest point; calyces are slightly club-shaped or barrel shaped, wider near the distal end than at the proximal point of attachment to the stolon.

The oral disk expands into a broad circular membrane by fusion of the proximal regions of the adjacent tentacles (Figure 2c). The margin of the oral membrane has eight broad lobes, with eight deep furrows, which run from the intertentacular margin to the mouth of the polyp, giving a plump appearance. The distal two-thirds of the tentacles extend from fused margins of the oral membrane. Tentacles are long and thin, with eight pairs of widely spaced pinnules, which are arranged in a single row on either side of the rachis.

Anthocodial sclerites are rods with sparse simple tubercles around margins 0.07-0.24 mm long and rods ornamented with clustered tubercles on one end, giving it a club-shaped appearance, size 0.10-0.18 mm (Figure 4a). Calyx containing small capstans 0.02-0.05 mm long (Figure 4b) and table-radiates ranging 0.03-0.09 mm (Figure 4d). Sclerites of stolon are fused table-radiates forming a flat network (Figure 4c).

The oral disk and tentacles are white in life with brown in the proximal part of tentacle (Figure 2c), yellowish-white in ethanol. Zooxanthellate.

Morphological variation.

Paratypes consist of colonies with 30-100 polyps, growing on hard substrates. Colonies show variations in the tentacles, sometimes having ten pairs of pinnules.

Distribution.

The south-east of Palau in the Philippine Sea and the north to north-east reef of Dongsha Atoll, Taiwan in the South China Sea.

Remarks.

Hana hanagasa and Hana hanataba have very similar polyp morphology, with minor colour differences, which could be due to differing abundances of zooxanthellae. Genetic data and sclerite morphology indicate that H. hanagasa and H. hanataba should be separated from each other at the species level. Sclerites found in H. hanataba are different from those in H. hanagasa in the presence of ornamented rods, which are lacking in H. hanagasa . It is noteworthy that both H. hanagasa and H. hanataba were found in environments with the presence of a comparatively strong current.

Etymology.

From the Japanese language ' hanataba ' (花束), meaning bouquet; denoting the multitude of polyps resembling arranged flowers.