Prionocidaris baculosa ( Lamarck 1816 )

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 : 11-13

Prionocidaris baculosa ( Lamarck 1816)

FIGURE 3A–E

Comments

Figure 3 A-D documents the first occurrence of this species from Hong Kong, where it was recorded from the Ninepin Islands at 18.0 m. This species occurs between 10-30 m in rocky habitats from this region.

Prionocidaris baculosa has been recorded previously from China and throughout the Indo-Pacific, specifically from Japan to the west coast of Australia, the Philippines, the Indonesian region and in the Indian Ocean from Ceylon, the Red Sea and Mauritius, between depths of 0 to 250 m ( Liao & Clark 1995; Schultz 2015).

Feeding observations of this species are included in the Discussion.

In situ and aquarium observations

In situ observation of one individual ( Fig. 3A ) showed a majority of spines carrying fouling materials on them, with only approximately five spines in view without any fouling growth. These spines appear to be shorter and could represent spine loss from predators or other damage or possibly there is preferential fouling growth on the more elongate spines. Reasons for this preferential growth are unclear.

Under aquarium conditions ( Fig. 3B–D ), one individual was observed attacking two asteroids, including Luidia maculata ( Fig. 3B ) and the oreasterid Culcita novaeguineae suggesting predatory tendencies. These were not observed in the field.

Occurrence/Distribution

Hong Kong, 10–30 m.

Outside Hong Kong: southern China, in the vicinity of Hainan Island, and throughout the Indo-Pacific , Japan to the west coast of Australia, the Philippines, the Indonesian region and in the Indian Ocean from Ceylon, the Red Sea and Mauritius, between depths of 0–250 m.

Figures

FIGURE 3. Prionocidaris baculosa A. Prionocidaris baculosa in proximity to soft coral Scleronephthya, upon which it was presumably feeding. B. Laboratory predation on the luidiid Luidia maculata. C. Laboratory predation on the oreasterid, Culcita novaeguineae. D. Closeup on Culcita novaeguineae showing predation damage around adambulacral region by P. baculosa. E. Specimen with Ophiactis brittle stars present on spines. Photographer: Sam King Fung Yiu.