A new star for Singapore: discovery of sea star

Discovery of large five-rayed sea star adds to marine biodiversity here
David J.W. Lane , Robin Ngiam & Ivan Tan, Straits Times 3 May 08;

SINGAPORE has a new star to call its own.

This large five-rayed sea star is not new to science, but it is a new and spectacular addition to Singapore's already substantial inventory of living stars.

Lacking a common name but known in the marine science world as Pentaceraster mammillatus, it is in the same family as the more familiar cushion star and the knobbly sea star, which are still quite common on Singapore's remaining reefs.
The 'mammillatus' part of the name refers to the rows of nipple-like protuberances that cover the surface of the animal and give it a studded or armoured appearance.

The sea star was first sighted early last month on a seagrass monitoring trip at Cyrene reef, run by volunteer group TeamSeagrass and staff from the National Biodiversity Reference Centre of the National Parks Board (NParks).

The specimen baffled those who found it, all of whom had their own version of what to name the new find - which was at once familiar, yet strangely alien.

Names like 'Darth Vader star' and 'knobbly-wannabe' were bandied about as the group debated what it could possibly be.

Fast forward to a week ago: Armed with a permit, an enthusiastic search party made up of staff and students from the National University of Singapore's Raffles Museum of Biodiversity Research, NParks and others - including visiting regional echinoderm specialist David Lane - set out for a dawn low-tide walk on Cyrene reef. (Echinoderms are marine animals that exhibit five-fold radial symmetry at some stage of life.)

Right at the end of the trip, as the tide was rising and time was running out, the object of the mission was located, almost hidden in a dense field of seagrass.

A rare and exciting find

THE discovery of this attractive species, one of about a dozen of its kind in the Indo-Pacific, is in some respects a remarkable surprise, given its large size and the fact that sea stars and their relatives had been intensively surveyed and studied throughout the 1990s by a team of NUS and Belgian marine scientists.

Another surprise is that this star was previously known to exist only in the western Indian Ocean and the Red Sea, so its presence in Singapore waters represents a considerable range increase.

It must be stated, however, that the taxonomy of this group has some uncertainties, with gradations between species, possible hybrids and a closely related form living in the Philippines region.

Nevertheless, the find is an important one in biodiversity terms.

The latest individual discovered, at 27cm in diameter, is smaller than the one seen previously, so a small population may exist in the dense seagrass of Cyrene, and possibly elsewhere locally.

Cyrene reef: Rich in marine life

SITTING in the midst of intensive port activities, not far from the huge container terminal of Pasir Panjang, this patch reef stands like a marine oasis - a trove of biodiversity in the midst of the nation's economic pulse.

This sandy reef, swept clean of silt by strong currents when the tide is in, is as rich now biologically, if not richer, than in the 1990s.

Recent and earlier treasure hunts have unearthed numerous species of sea stars, sand dollars, sea urchins and sea cucumbers, in addition to many other invertebrate species.

That all this marine life exists in the middle of one of the busiest port zones in the world attests to the cleanliness of the seawater environment. Marine life thrives where water currents are sufficient to prevent smothering by sedimentation.

Singapore owes its rich marine biodiversity heritage to the fact that it is equatorial, that it is close to the edge of the 'coral triangle' biodiversity hot spot of the Indo-Malay archipelago, and also to overlapping ranges of Pacific and Indian Ocean faunas.

The Republic is clearly at the centre of things in many ways.

Why is the continued existence of this kind of marine life in Singapore so important?

There is a host of reasons, many of which have to do with the quality of the marine environment and, directly or indirectly, with the quality of human life and the growing environmental awareness in crowded Singapore.

A rich diversity of marine life is often cited as a potential source of new medicinals or of target species for cultivation. An equally important value is that the continued existence - or otherwise - of rich and diverse marine communities provides an overall measure for monitoring the ecosystem and environmental health status.

Additionally, the recreational and educational value of natural resources and the environment will undoubtedly continue to grow in Singapore, as these resources become more and more scarce.

Unique to Cyrene is the fact that there are three different habitats - sea grass, coral reef and sand - amalgamated on one reef.

Other exotics, such as sea horses recently sighted there, are perhaps additional indicators of the conservation value of this reef formation.

An important objective in relation to this conservation issue would be an urgent survey programme for this new star, and other rarities, on the remaining untouched and relatively unexplored reef flats in the Southern Islands.

Dr Lane is a senior lecturer and marine scientist with Universiti Brunei Darussalam. Formerly with NUS, he continues to work closely with its Raffles Museum of Biodiversity Research, the region's premier natural history museum. Mr Ngiam is a project officer with NParks, while Mr Tan is an education and public relations officer with the Raffles Museum.

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