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ISSN : 1226-9999(Print)
ISSN : 2287-7851(Online)
Korean J. Environ. Biol. Vol.38 No.4 pp.563-566
DOI : https://doi.org/10.11626/KJEB.2020.38.4.563

Newly recorded sea star Henricia oculata (Asteroidea: Spinulosida: Echinasteridae) in the East Sea, Korea

Michael Dadole Ubagan1, Sook Shin1,2,*
Department of Animal Biotechnology & Resource and Marine Biological Resource Institute, Sahmyook University, Seoul 01795, Republic of Korea
*Corresponding author Sook Shin Tel. 02-3399-1717 E-mail. shins@syu.ac.kr
03/11/2020 08/11/2020 09/11/2020

Abstract


Henricia specimens were collected using fishing nets from the East Sea of Korea. The specimens were identified as Henricia oculata Pennant, 1777, belonging to the family Echinasteridae of the order Spinulosida. This species can be distinguished from other Henricia species by broad arms (R/r=4-4.1), rough skin, a thick arm base, three to nine minute delicate abactinal spines, and inferomarginal plates reniform in shape. This species superficially resembles H. pachyderma in its body size and wide papular areas but differs mainly in the number of papulae and abactinal spines, and the shape and arrangement of the inferomarginal plates. To date, two genera of Echinasteridae, Aleutihenricia and Henricia, with a total of 13 species, have been reported in Korea. The morphological characteristics of H. oculata are described, and photographs are provided.



초록


    National Institute of Biological Resources(NIBR)
    202002204Ministry of Oceans and Fisheries(MOF)
    20190518

    INTRODUCTION

    The family Echinasteridae is currently populated by eight genera, of which two genera, Aleutihenricia and Henricia, are present in the Korean fauna. Henricia is the most diverse of the echinasterid genera and includes 94 described species. Although Henricia species are well distributed worldwide, the complexity of the morphological characteristics in several of the recognized species has been poorly described. Historically, the taxonomy of Henricia has been based on traditional morphology, using the main diagnostic characteristics from the abactinal and actinal morphological characteristics (i.e., the shape and number of abactinal and actinal spines, the shape of abactinal and actinal skeletons, and the number of adambulacral spines). Previous taxonomic research performed on Henricia spe- cies in the western Pacific (Fisher 1911;Djakonov 1940;Hayashi 1940) was a major contribution to the classification of this group of species. In the classification of Henricia species, individual species cannot be correctly separated based on only one characteristic. Moreover, only a set of individual characteristics that can reliably separate species has been used for Henricia identification (Bratova and Paskerova 2017). Currently, 11 Henricia species have been recorded in Korea (Ubagan and Shin 2019a, b, c, 2020): H. anomala Hayashi, 1973; H. elachys Clark & Jewett, 2010; H. leviuscula Stimpson, 1857; H. nipponica Uchida, 1928; H. ohshimai Hayashi, 1935; H. pachydermaHayashi, 1940;H. pacificaHayashi, 1940;H. perforata (O.F. Müller, 1776); H. regularisHayashi, 1940;H. reniossaHayashi, 1940; and H. sanguinolenta (O.F. Müller, 1776). Most Henricia species are distributed in the East Sea of Korea.

    MATERIALS AND METHODS

    The Henricia specimens were collected from waters near Namae and Shinnam, Korea, using fishing nets on March 3, 2014, and September 12, 2014, respectively. The collected specimens were preserved in 95% ethanol, and the following morphological characteristics were examined: the size of the disk, upper and proximal portions of the arms, number of abactinal spines, shape of the abactinal and actinal skeleton, and number of adambulacral spines. The morphological features of the specimens were photographed using a scanning electron microscope ( JSM-6510; JEOL Ltd., Tokyo, Japan), a stereomicroscope (Nikon SMZ1000; Nikon Co., Tokyo, Japan), and a digital camera (Nikon D7000). The abbreviations for the measurements were those used by Ubagan and Shin (2019a).

    SYSTEMATIC ACCOUNT

    Class Asteroidea de Blainville, 1830

    Order Spinulosida Perrier, 1884

    Family Echinasteridae Verrill, 1870

    Genus Henricia Gray, 1840

    Henricia oculata Pennant, 1777

    거친애기불가사리 (신칭) (Fig. 1A-K)

    Henricia oculata Pennant, 1777: Madsen, 1987: pp. 254- 257, figs. 44-45; Clark and Downey, 1992: p. 393, pls. 93e, 95f-g, figs. 60q-r; Jewett et al., 2012: p. 160, fig. 9d; Mah, 2020: 123970.

    Material examined. One specimen: Namae, 3 March 2014, MERBK-A-1257; one specimen: Shinnam, 12 September 2014, MERBK-A-1258, fishing net, Shin, S. and Lee, T.

    Description. Arms five, slightly broad arm base, gradually tapering to tips (Fig. 1A, B). Abactinal paxillae clustered, containing three to nine minute spinelets, more or less in a curved series around the papular area, and covered with rough skin (Fig. 1C). Papular areas wide, containing two to six papulae in an area (Fig. 1H). Abactinal skeleton open-meshed, reticulated, comprising rod-like, small ossicles present inside papular areas (Fig. 1G). Madreporite situated near center of disk, circular in form, not elevated, and bearing spines larger than abactinal spines (Fig. 1F). Actinal plates close-meshed, with narrow spaces of papular areas with one or two papulae larger than abactinal plates. Superomarginal, intermarginal, inferomarginal, and ventrolateral plates distinguishable. Superomarginal plates bearing five to nine spines, reaching tip of arm. Intermarginal plates formed longitudinally between inferomarginal and superomarginal plates, containing a wide area on actinal side, reaching three-quarters length of the arm. Inferomarginal plates reniform in shape, compact, bearing three to six spines, and larger than surrounding plates. Ventrolateral plates rounded cross shape, compact, bearing four to six spines, reaching one-half length of arm (Fig. 1I). Adambulacral armature comprising three to eight bluntly pointed spinelets; inner spine being longer and more spatulate than outer spines, and arranged in two transverse or zigzag rows (Fig. 1D, K). Oral plate bearing two slender, flat tip spines (Fig. 1E). Furrow spine single.

    Size. R=76-92 mm, r=19-22 mm, R/r=4-4.1.

    Habitat. Hard substrates (rocks).

    Color. Body color was light brown in alcohol.

    Korea. East Sea (Namae, Shinnam).

    Distribution. Korea (East Sea), Alaska (Akun Island, Kodiak Island), France, Ireland, Portugal, and the United Kingdom (British Isles, England, Scotland, Wales).

    Deposition. The collected specimens were deposited in the Marine Echinoderm Resource Bank of Korea, Sahmyook University, Seoul, Korea.

    Remarks.Henricia oculata was first described as Asterias oculata by the British zoologist Thomas Pennant, 1777, and was later transferred under Henricia. Our specimen superficially resembled that of H. pachyderma in its size, wide papular areas, the conical shape of the abactinal spines, and flat-tipped adambulacral spines. It differs mainly from the similar H. pachyderma in the number of papulae (H. oculata: 2-6; H. pachyderma: 1-3), the number of abactinal spines (H. oculata: 3-9; H. pachyderma: 5-13), the shape of inferomarginal plates (H. oculata: reniform; H. pachyderma: transversely elongated), and the arrangement of inferomarginal plates series (H. oculata: compact; H. pachyderma: loose). In comparison with other Henricia species bearing broad arms, our morphological analysis showed that it differed from H. perforata in the shape of abactinal spines (H. oculata: conical; H. perforata: slender), the shape of inferomarginal plates (H. oculata: reniform; H. perforata: transversely elongated), and the arrangement of the series of inferomarginal plates (H. oculata: compact; H. perforata: loose) (Table 1). Our specimens H. oculata have slight morphological differences compared to the Atlantic H. oculata. Previously, H. oculata abactinal plates had been crowded with abactinal spines (up to 25 in numbers) in multiple rows (Madsen 1987), but our specimens possessed lesser number of abactinal spines (three to nine). However, differences in the number of abactinal spines alone cannot be regarded as a stable character for Henricia species identification (Bratova and Paskerova 2017). Therefore, we consider that Korean H. oculata is the same species as the Atlantic H. oculata. H. oculata is reported for the first time in the Korean fauna.

    ACKNOWLEDGEMENTS

    This study was supported by a grant from the National Institute of Biological Resources (NIBR), which was funded by the Ministry of Environment of the Republic of Korea (NIBR 202002204), and the project titled “Improvement of management strategies on marine disturbing and harmful organisms” funded by the Ministry of Oceans and Fisheries, Korea (No. 20190518) and the Marine Biotechnology Program of the Korea Institute of Marine Science and Technology Promotion (KIMST) funded by the Ministry of Oceans and Fisheries (MOF) (No. 20170431).

    Figure

    KJEB-38-4-563_F1.gif

    Henricia oculata. A. abactinal side; B. actinal side; C. abactinal paxillae; D, K. adambulacral spines; E. oral part; F. madreporite; G. abactinal skeleton; H. papulae (arrows); I. actinal skeleton: superomarginal plates (s), intermarginal plates (in), inferomarginal plates (i), ventrolateral plates (v), adambulacral plates (a); and J. abactinal spines. Scale bars: A, B=1 cm, C-I=1 mm, J=100 μm, K=500 μm (J, K, SEM images).

    Table

    Comparison of morphological characteristics between H. oculata and related Henricia species reported in Korea

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