Anthenea chinensis Gray 1840

Yiu, Sam King Fung & Mah, Christopher L., 2024, New Ecological Observations and Occurrence for Asteroidea and Echinoidea in Hong Kong, Zootaxa 5526 (1), pp. 1-69 : 51-54

Anthenea chinensis Gray 1840

FIGURES 38A–D , 39A–B

Comments

Our account follows Liao & Clark’s (1995) treatment, which recognizes the East Asian Anthenea species as Anthenea chinensis , a separate species from the Australian Anthenea pentagonula , into which A. chinensis had been synonymized. Liao & Clark (1995) argued that individuals of this species in East Asian waters are better separated from those identified from Australian settings. We adopt this perspective for the simple reason that other than “ Anthenea ” (now placed into Gymnanthenea ) difficilis , all of the other species noted from south Chinese waters in Liao & Clark (1995) show few to no clear character differences from one another or other populations in the East Asian region but do show character differences from Australian species.

For example, Liao & Clark (1995) indicate that Anthenea aspera Doderlein 1915 shows overlapping R/r of 1.5 to 2.1 throughout its range with few other definitive characters which clearly distinguish it from Anthenea chinensis . It is unclear if Anthenea aspera , as seen in Singapore for example ( VandenSpiegel et al. 1998) is actually distinct from Anthenea chinensis sensu Liao & Clark (1995) . Specimens studied herein showed R/r of 2.07 to 2.28 which exceeds all of the known species from the south China seas save for the highly variable A. chinensis as outlined by Liao & Clark (1995) which showed a range of 1.6 to 2.1. The Singaporean Anthenea aspera was figured by Marsh & Fromont (2020) also shows only 3 to 4 thick furrow spines which is consistent with those observed in Hong Kong Anthenea specimens herein as well as “ Anthenea aspera ” as figured by Mortensen (1934). This contrasts with the 6 to 7 “slender” furrow spines outlined for the Australian Anthenea aspera in Doderlein (1915).

Although recorded from Hainan Island, Anthenea viguieri has not been recorded from Hong Kong and as such, falls outside of the scope of this treatment. However, Liao & Clark (1995) address the fact that it is likely a further part of the Anthenea chinensis complex rather than a separate species.

Diagnosis

Body pentagonal to stellate (R/r=1.6 to 2.28). Three series of adambulacral spines, one furrow spine series with 3 to 5 spines, two series of subambulacral spines. Subambulacral spines adjacent to furrow spines with 2 to 3 spines, each thick and round.

Occurrence/Distribution

Hong Kong, 5 m.

Outside Hong Kong. Okinawa, Japan, Gulf of Tonkin to Fujian Province , 0–60 m.

Description

Body stout, thick, stellate in outline (R/r=2.07–2.28), arms triangular, interradial arcs curved. Body surfaces covered by a dermis with an invested granular cover. Granular cover and morphology variable with different surfaces ( Fig. 39A ).

Abactinal surface, formed of an elaborate reticulate network composed of large round plates with smaller secondary plates abutted between them ( Fig. 39A ). Along carinal series and widespread over interradial regions, secondary plates with short, conical-shaped spines. Plates extend from disk to arm tip. Between plates, large papular areas, each with 3–15 papulae present in each discrete region. Larger plates arranged in linear rows with secondary plates forming transverse lineation, creating triangular to papular regions which on a minority of papular regions are weakly confluent with some papular overlap. When plates are cleared, they show embossed glassy granules present in the surface, 10–70 per plate. Pedicellariae one to three, with mostly two, but exceptionally three clam-shaped valves, variably round to quadrate, each with smooth surfaces present widely over abactinal surface. Surficial dermis inundated with densely packed array of small granules with pointed tips, approximately 3 along a 1.0 mm line, widely spaced from one another. These granules appear to be slightly larger and more abundant in larger individuals (R>5.0 cm). A bare seam, devoid of spination and large plates present along each interradius. Pointed granules smaller in this area and more widely distributed from one another. Papular regions widespread along disk and arms, but absent interradially, especially along narrow central patch confluent with interradial superomarginal seam. Madreporite approximately 3 to 5 mm in diameter in individuals with R=4.0 to 6.0, each plate, flanked by three to five plates, with convex surface and well-developed sulci. Madreporite periphery surrounded by coarse granules and large tubercles.

Marginal plates 26–28 per interradius at R=4.0 to 6.0, approximately 13 or 14 per arm ( Fig. 39A–C ). Individual plates wide, forming distinct border around abactinal surface ( Fig. 39B ). No superomarginals abutted along arm. Both superomarginal and inferomarginal plates with one to three bivalve pedicellariae. Granular dermis continuous over abactinal, marginal surface. Superomarginals occupy approximately 10–12% of total “r” distance on disk (0.25 to 0.3/ 2.5 cm). Individual superomarginal plates with strongly convex, round dorsolateral edge and is round in cross-section. Superomarginal plates covered by granule-invested epidermis which covers abactinal surface. Larger granules embedded in dermis present, coarse, round 10–30 per plate present on plate central surface, absent from peripheral region adjacent to abactinal plates where smaller pointed granules are present. Inferomarginal plates covered by dense granular cover with coarse, round granules, 10–60, mostly 40, approximately 3 counted along a 1.0 mm line, closely arranged but evenly and widely spaced. Pedicellariae on actinal surface of inferomarginal plate surface. Terminal plate triangular covered with granule-infused tissue, but when cleared, covered with embossed glassy granules. Shallow fasciolar groove present between marginal and actinal plates.

Actinal intermediate areas composed of three full series in chevron formation plus irregular plates present adjacent to inferomarginal contact ( Fig. 39C ). Actinal plates irregularly polygonal to round, largest proximally becoming smallest and more irregular in shape distally, adjacent to inferomarginal contact. Granules large, round, 4–20 present on peripheral surface of all plates but only covering plate surface completely distally adjacent to inferomarginal plates. Most proximal actinal plates covered by large bivalve, exceptionally one trivalve per interradius, pedicellariae, which nearly bisects the plate on which it sits. Pedicellariae on nearly every plate on actinal series adjacent to the adambulacral plate series ( Fig. 39D ).

Adambulacral plates with three spine series, one furrow series on groove and two subambulacral series on plate surface ( Fig. 39D ). Furrow spines, 4 to 5, largest spines, thick, club-like in shape present centrally with two short spines approximately 10% of the height of the large central furrow spines, all arranged in a weakly convex to straight fan. Furrow spines set off from subambulacral spines by discrete space. Subambulacral spines 2 to 3, at least one spine, twice as thick as furrow spines, approximately 10% longer, especially on distal plates where they become thicker and much rounder.Adjacent and/or behind the enlarged subambulacral spine is a large paddle-shaped pedicellariae, comparable in size to subambulacral granules on adambulacral plate and actinal plate surfaces ( Fig. 39D ). Remainder of subambulacral accessories, granules, approximately three present, each round, thick similar in size than granules on actinal surface, but set off from these granules by a discrete space.

Oral plate with furrow spines, six, blunt, thick, quadrate to round in cross-section with paired spines projecting into mouth, quadrate in cross-section, elongate, approximately 10% longer than other oral plate furrow spines. Oral plate surface with two series, each with 6 to 8 short, blunt, thick spines on either side of the fossae between the two oral plates.

Material Examined

Hong Kong, China. CASIZ 113389 , breaker reef, Hong Kong, China, 22º 27.78N 114º25.11’E, 2 wet specs. R=8.7 r=4.2; R=6.2 r=2.9

USNM 3036 Hong Kong. Coll. W. Stimpson, North Pacific Exploring Expedition. 3 wet specs. R=6.1 r=2.8, R=5.7 r=2.7, R=5.7 r=2.5

Figures

FIGURE 38. Anthenea chinensis USNM 3036. A. Abactinal. B. Abactinal-superomarginal closeup. C. Actinal. D. Closeup actinal surface. Scale bar: 10.0 mm=A, C. Scale bar: 5.0 mm=B, D.

FIGURE 39. Anthenea chinensis in situ A. In situ showing abactinal of light color variant. B. In situ showing dark color variant. C. In situ, living color actinal surface. Photographer: Sam King Fung Yiu.