Luidia sea star
elegant and active sea star is sometimes seen on our Northern shores,
on soft, silty shores, near seagrass meadows and coral rubble. It
is usually seen alone, and not in large groups. It moves rapidly and
is usually more active at night.
Diameter with arms to 12-20cm. 5 to 9, usually 8 arms. The arms are
long, somewhat rounded in cross-section, and tapered to a sharp tip,
edged with small sharp spines along the sides. The upper surface of
the body is covered with special flat-topped, pillar-like structures
called paxillae. The underside is pale, and from grooves along the
arms emerge large tube feet with club-like, pointed tips. Colours
and patterns on the upperside are highly variable in shades of greyish
blue, to brown and beige, but usually with a darker star-shaped pattern
in the centre, and dark irregular bars along the length of the arms.
Sometimes mistaken for the Common
sea star (Archaster typicus). The Common sea star has large
tube feet with sucker-shaped tips, while the Eight-armed sand star
has large tube feet with pointed tips.
What does it eat? According to
Lane, it burrows in soft sediments and feeds on small buried animals
such as molluscs and other echinoderms. Coleman has a photo of this
sea star eating another sea star!
Status and threats: According
to Lane, the Eight-armed sand star used to be common on our mainland
shores. It is now listed as 'Endangered' on the Red List of threatened
animals in Singapore. It was formerly found near the mainland prior
to reclamation but recently known only from the Pulau Ubin and Pulau
Tekong area in low numbers.
A huge one bigger than my foot!
Pulau Sekudu, Apr 06
Pointed tube feet.
Flat-topped, pillar-like structures called paxillae.
Close up of the mouth.
Luidia sea stars on Singapore shores
With five arms.
Changi, May 16
Photo shared by Marcus Ng on facebook.
shared by Loh Kok Sheng on his
Jul 09 |
Tanah Merah, May 13
shared by Loh Kok Sheng on flickr.
Cluster of many large sea stars.
Pasir Ris, Jul 18
Shared by Richard Kuah on facebook.
Tuas, Mar 15
shared by Loh Kok Sheng on his blog.
In spawning position?
East Coast, Dec 08
Pulau Semakau, Aug 11
- Lane, David
J.W. and Didier Vandenspiegel. 2003. A
Guide to Sea Stars and Other Echinoderms of Singapore.
Singapore Science Centre. 187pp.
- Didier VandenSpiegel
et al. 1998. The
Asteroid fauna (Echinodermata) of Singapore with a distribution
table and illustrated identification to the species. The Raffles
Bulletin of Zoology 1998 46(2): 431-470.
G.W. H. and P. K. L. Ng and Ho Hua Chew, 2008. The Singapore
Red Data Book: Threatened plants and animals of Singapore.
Nature Society (Singapore). 285 pp.
Sabine, 2000. Echinoderms
of the Philippines: A guide to common shallow water sea stars,
brittle stars, sea urchins, sea cucumbers and feather stars.
Times Edition, Singapore. 144 pp.
Neville. 2007. Sea
stars: Echinoderms of Asia/Indo-Pacific. Neville Coleman's
Underwater Geographic Pty Ltd, Australia.136pp.
Terrence M., David W. Behrens and Gary C. Williams. 1996. Coral
Reef Animals of the Indo-Pacific: Animal life from Africa to Hawaii
exclusive of the vertebrates
Sea Challengers. 314pp.