INTRODUCTION

The family Echinasteridae is traditionally considered to have eight genera: Aleutihenricia Clark and Jewett 2010; Dictyaster Wood-Mason and Alcock 1891; Echinaster Müller and Troschel 1840; Henricia Gray 1840; Metrodira Gray 1840; Odontohenricia Rowe and Albertson 1988; Plectaster Sladen 1889; Rhopiella Fisher 1940. The genus Henricia has a complex taxonomic history as many species have now been assigned to this genus (Fisher 1911;Hayashi 1940;D’yakonov 1950). Currently, the world fauna record of genus Henricia which include 94 valid species (Wakita et al. 2019), 11 of which are present in Korean fauna. However, this is considered as an underestimation of the real number of species in this diverse genus and it is likely that more species remain unidentified. Some of the previously recognized species within this genus are poorly described, and the identification of the present group of species is vague. However, several taxonomists have provided an important overview of the systematic identification and imparted a major contribution to the complex morphological variations of Henricia species (Clark and Downey 1992).

MATERIALS AND METHODS

The Henricia specimens were collected from the waters near Jukbyeon and Jumunjin, Korea, using fishing nets on May 25, 2013, and August 29, 2014, respectively. The collected specimens were preserved in 95% ethanol, and the morphological characteristics were examined, such as the size of the disk, the upper and proximal portions of the arms, the number of abactinal spines, the shape of the abactinal and actinal skeleton, and the number of adambulacral spines. The morphological features of the specimens were photographed using a scanning electron microscope ( JSM-6510; JEOL Ltd., Tokyo, Japan), stereomicroscope (Nikon SMZ1000; Nikon Co., Tokyo, Japan), and digital camera (Nikon D7000). The abbreviations for the measurements were those used by Ubagan and Shin (2019).

SYSTEMATIC ACCOUNT

Class Asteroidea de Blainville, 1830

Order Spinulosida Perrier, 1884

Family Echinasteridae Verrill, 1870

Genus Henricia Gray, 1840

Henricia perforata (O.F. Müller, 1776) 구멍애기불가사리 (신칭) (Fig. 1A-K)

Henricia perforata: Madsen, 1987: pp. 243-254, figs. 3a, 31-43; Bratova and Paskerova, 2017: pp. 347-348, figs. 4a-4g; Mah, 2020: 123971.

Material examined. Two specimens, Jukbyeon, 25 May 2013, fishing net, Shin and Lee; one specimen, Jumunjin, 29 Aug. 2014, fishing net, Shin and Lee.

Description. Arms five; slightly broad arm base, gradually tapering to tips (Fig. 1A, B). Abactinal paxillae scattered, containing two to six small, delicate spinelets covered with thin integument. Wide papular areas, containing two to seven papulae in an area (Fig. 1C). Abactinal skeleton, open meshed, reticulated, composed of rod-like plates, small ossicles present within papular areas (Fig. 1H). Madreporite small, situated near center of disc, circular in form and bearing spines, same as abactinal spines (Fig. 1F). Both superomarginal and inferomarginal plates distinguishable, reaching tip of arm. Intermarginal plates contains wide spaces between inferomarginal and ventrolateral plates. Ventrolateral plates reaching three-quarters of arm length (Fig. 1I). Adambulacral armature comprising five to seven long (1.3-2.2 mm), slender spinelets, with inner spine being longer than outer spines arranged in two transverse or in zigzag rows (Fig. 1D). An oral plate bearing two slender spines (Fig. 1E). Furrow spine single.

Size. R=54-72 mm, r=13-16 mm, R/r=4.1-4.5.

Habitat. Hard substrates (rocks).

Color. Body color was light brown in alcohol.

Korea. East Sea (Jukbyeon, Jumunjin).

Distribution. Korea (East Sea), NE Atlantic: Greenland Sea, North Sea (from northern British Coast, Kattegat, Skagerrak to Norwegian Coast), Norwegian Sea. NW Atlantic: Baffin Sea, Hudson Bay, Labrador Coast. Arctic: Barents Sea, Kara Sea, Laptev Sea, East Siberian Sea.

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

Remarks. This species has been recorded in the region of Skagerrak/Kattegat between southern Norway and Denmark and adjacent waters of Northern Atlantic (Madsen 1987;Bratova and Paskerova 2017). We compared our specimens to previously reported broad arms H. pachyderma in Korea and found the following differences: 1) the presence of slender to pointed tip adambulacral spines in H. perforata while stout shape in H. pachyderma; 2) by having more papulae in H. perforata (two to seven) compared with one to three in H. pachyderma; 3) the body of H. perforata was covered by thin skin, whereas the body H. pachyderma was covered by thick skin including spines. Our specimens H. perforata have some morphological differences compared to the North Atlantic H. perforata. In previous studies recorded that H. perforata had blunt tip adambulacral spines (Madsen 1987), but our specimens have slender to pointed tip. Furthermore, many Henricia species have broad geographic distributions; it is feasible that different populations might experience different environmental conditions that could result in morphological variations (Knott et al. 2018). Moreover, even though our specimens were found far from the region of origin (North Atlantic), we consider that Korean H. perforata is the same species as the Northern Atlantic H. perforata. This is the first report of H. perforata in the marine fauna of Korea.