Pentaceraster alveolatus ( Perrier 1875 )

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 : 58-59

Pentaceraster alveolatus ( Perrier 1875)

FIGURE 42A–B

Comments

Although this species has been recorded from southern China by Liao & Clark (1995), this represents the first occurrence of this species in Hong Kong.

Morphology and color of this species is highly variable across its range. Even for individuals in the Hong Kong area, several color and spine variations have been observed. Morphologically, some individuals show a much broader disk with more triangular arms (R/r=3.3–3.5) versus others with a smaller disk and narrower arms (R=2.3–2.8). Abactinal spine morphology also varies, with some individuals showing more conical and blunt tips versus others which show large, round tubercles with no pointed tips. Spine position appears consistent in observed individuals with disk spines occurring on the primary circlet and the carinal series irregularly present along the radius of each arm with few to no prominent spines on the abactinal-lateral regions of the disk and arms. Colors, show a highly diverse range among observed specimens, including red to orange with frosted white highlights and yellow spines, blue-gray with dark blue to black highlights with orange spines, to orange-brown with white spines and highlights.

One color morphotype of this species, showed a superficial resemblance with Poraster superbus in having more elongate arms and a higher R/r ratio (3.3 to 3.5) and round bulb-like carinal spines along the arms. Poraster superbus is apparently reported from Japanese waters ( Kogure & Igei 2013). However, specimens observed from Hong Kong demonstrate granules covering the bulb-like carinal spines and lack the interradial, inter marginal plates which characterize Poraster .

Occurrence/Distribution

Hong Kong, 10–15 m.

Outside Hong Kong. Hainan Island, Widely occurring throughout the Indo-Pacific. Southern Japan, China, Guam, New Caledonia, Samoa, Indonesia, Philippines, Western Australia, 1–54 m ( Marsh & Fromont 2020).

Figures

FIGURE 42. Pentaceraster alveolatus/P. sibogae A. In situ, abactinal surface. B. Abactinal surface showing pattern variation. C. & D. Pentaceraster sibogae. Feeding on urchin, Heliocidaris crassispina Photographer: Sam King Fung Yiu.