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| [a - b] Hana hanagasa & [c - f] H. hanataba
Lau, Stokvis, van Ofwegen & Reimer, 2018
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Abstract
A new genus and two new species of stoloniferous octocorals (Alcyonacea) within the family Arulidae are described based on specimens collected from Okinawa (Japan), Palau and Dongsha Atoll (Taiwan). Hana gen. n. is erected within Arulidae. Hana hanagasa sp. n. is characterised by large spindle-like table-radiates and Hana hanataba sp. n. is characterised by having ornamented rods. The distinction of these new taxa is also supported by molecular phylogenetic analyses. The support values resulting from maximum likelihood and Bayesian inference analyses for the genus Hana and new species H. hanagasa and H. hanataba are 82/1.0, 97/1.0 and 61/0.98, respectively. Hana hanagasa sp. n. and Hana hanataba sp. n. are the first arulid records for Okinawa, Palau, and Dongsha Atoll, and represent species of the second genus within the family Arulidae.
Keywords: Arulidae, COI, molecular phylogeny, mtMutS, north-western Pacific, octocoral, 28S rDNA, Stolonifera, taxonomy
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| Figure 2. In situ photographs of examined Hana specimens from Okinawa, a Hana hanagasa, holotype, OKA170711-15 and b Hana hanagasa, paratype, OKA170711-06; Palau c Hana hanataba holotype, ROR171225-01 and d Hana hanataba, paratype, ROR171226-03; Dongsha e Hana hanataba, paratype, DSX180320-1-01 and f Hana hanataba, paratype, DSX180324-3-15 g specimen BKI180320-2-10, an arulid photographed in Tunku Abdul Rahman Park, Sabah, Malaysia h Hana hanagasa, holotype, OKA170711-15, colony preserved in ethanol. Scale bar: 1 mm. |
Class Anthozoa Ehrenberg, 1831
Subclass Octocorallia Haeckel, 1866
Order Alcyonacea Lamouroux, 1812
Family Arulidae McFadden & Ofwegen, 2012
Type genus: Arula McFadden & Ofwegen, 2012
Diagnosis: (after McFadden and Ofwegen 2012). Alcyonacea with polyps that have tentacles that are fused proximally into a broad, circular oral membrane. Sclerites in the form of table-radiates.
Genus Hana gen. n.
Type species: Hana hanagasa, sp. n., by original designation.
Diagnosis: Colony with polyps connected through flat and thin ribbon-like stolons. Anthocodiae (retractile portion of polyp) retract into cylindrical to clavate calyces. Tentacles are fused proximally, forming a broad, circular oral membrane. The oral membrane has eight deep furrows, which run from the intertentacular margin to the mouth of the polyp, giving it a plump appearance. Sclerites of anthocodia are rods. Sclerites of calyx are 6-radiates and table-radiates. The main difference between Hana and Arula is in sclerites found in the type species Hana hanagasa sp. n. and Arula petunia in the stolon. Sclerites of the stolon are fused sheets that form a flattened network of table-radiates in H. hanagasa, while in A. petunia they are similar to the separate table-radiates found in the calyx. Additionally, there is a difference in sizes of the table-radiates, being longer in H. hanagasa than in A. petunia. Sclerites colourless. Zooxanthellate.
Etymology: From the Japanese language ‘hana’ (花), meaning flower; denoting the shape of the polyps, which resemble flowers. Gender: feminine.
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| Figure 1. Map of sampling sites at three locations in the north western Pacific; a Okinawa Island (Japan) b Dongsha Atoll (Taiwan); and c Palau. |
Hana hanagasa sp. n.
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Distribution: Northwest coast of Okinawa Island and southeast coast of Iheya Island in the East China Sea.
Remarks: Arula and Hana are the only two genera within the family Arulidae. Arula petunia and H. hanagasa have very similar polyp morphologies with only a clear difference in polyp colour. Oral disk and tentacles of A. petunia are blue in life and white and brown in H. hanagasa, respectively. This would suggest assignment to the same genus, however, the combination of differences in genetic data and sclerite morphology indicate that they should be separate from each other at the generic level. The possibility that there are similar species or previous descriptions and reports on arulid species has previously been discussed (McFadden and Ofwegen 2012) and so far, no reports have been made on possible congeners.
Etymology: From the Japanese language ‘hanagasa’ (花笠), the traditional Okinawan ceremonial dance headpiece worn by female performers; denoting the shape of the polyps, which resembles the flower headpiece.
Hana hanataba sp. n.
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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.
Yee Wah Lau, Frank Robert Stokvis, Leendert Pieter van Ofwegen and James Davis Reimer. 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: 1-19. DOI: 10.3897/zookeys.786.28875
