Just heard from Sijie that the Star of Cyrene has been tentatively identified as Pentaceraster mammillatus by Dr. David Lane. Sijie adds in his updated nature scouter blog entry:
Its distribution is that of Indian Ocean, but apparently with its appearance in Singapore, it has expanded its range. It is usually found in lower eulittoral and deeper region, on sand and seagrasses. However, the taxonomy of this group has some uncertainties, with gradations between species, possible hybrids and a closely related form living in the Philippines region.Some of the volunteers have been calling it the Black Evil Star, because it is so different from our more commonly seen lovable cuddly Knobbly sea stars (Protoreaster nodosus).The Special Star has a much more regular pattern and is dark so I guess it does appear rather sinister compared to the bright red and rather cartoon-like Knobbly.It's the first record of Pentaceraster on Singapore's shores so this suggests Cyrene Reef is a special place. We're all very excited by this! Bravo!