learn only 3 things about them ...
can be very long!
are predators and efficient hunters.
They are delicate and some are venomous. Don't touch!
Ribbon worms regularly seen in coral rubble areas on many of our shores.
They are more active at night. During the day, they burrow in the
ground or remain in other hiding places.
What are ribbon worms? Ribbon
worms are unsegmented worms belonging to
Phylum Nemertea. They are quite different from the segmented worms
that we are more familiar with such as earthworms and bristleworms.
These belong to Phylum Annelida. According to the
Nemertes website, there are approximately 1,000 valid, described
species of ribbon worms, with possibly several times this number that
remain to be named or discovered! Ribbon worms are found in oceans,
freshwaters, and also on land.
Features: Ribbon worms range in
length from 1mm to very long ones indeed. Some species can reach 30m!
Those we have seen range from short ones 10-15cm long, longer ones
30-40cm long and some more than 1m long. Ribbon worms are NOT segmented
worms. The body of a ribbon worm is rather flattened. Although it
appears smooth, the body is covered with microscopic hairs (cilia).
Ribbon worms may have zero to 80 'eyes' (light-dectecting sensors).
Some ribbon worms produces mucus through which they move.
What do they eat? Most ribbon
worms are voracious predators, often specialising in a particular
prey although some will eat a wide variety of prey. Ribbon worm prey
include other worms, crustaceans and molluscs.
Shooting off its mouth: To capture
its prey, the ribbon worm has a unique eversible proboscis at the
front end of the body. This is a hollow, muscular structure that can
shoot out with explosive force and is prehensile (can be used to grip)
and retractable (can be pulled back). The proboscis is usually wound
around the prey which is then hauled back toward the worm's mouth.
Sticky mucus is secreted to help grip the prey.
In one group of ribbon worms, the proboscis is armed with a piercing
stylet that can inject a potent paralysing toxin. Such a worm releases
the prey after injecting it, and waits for the prey to be paralysed
before moving in to feed on it. If the prey is worm-shaped, it may
be swallowed whole. For other awkwardly shaped prey, the worm inserts
part of its digestive system into the prey and sucks up the victim's
juices. The proboscis may also be used to burrow or to drag itself
along the surface.
Being soft and very long, ribbon worms appear defenceless. Studies,
however, suggest that they harbour bacteria that produce powerful
neurotoxins. These may make the worms toxic to eat. Indeed, many ribbon
worms are brightly coloured, perhaps serving to warn of their distasteful
Ribbon worm babies:
Most ribbon worms have separate genders. A few may change from being
a male to a female as they get older and larger. Fertilisation is
external and the young are free-swimming larvae. A few species of
ribbon worms can reproduce by fragmentation.
swimming in the water.
Tuas, May 05
a paralysed shrimp.
Pulau Hantu, Mar 07
around a drill snail.
Labrador, May 06
one can be more than 1m long.
Terumbu Pempang Darat, Jun 10
Nemertea recorded for Singapore
Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity
in red are those listed among the threatened
animals of Singapore from Davison, G.W. H. and P. K. L. Ng
and Ho Hua Chew, 2008. The Singapore Red Data Book: Threatened
plants and animals of Singapore.
worms commonly seen awaiting identification
*Species are difficult to positively identify without close
On this website, they are grouped by external features for convenience
sp. (EN: Endangered)
- Wee Y.C.
and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore.
National Council on the Environment. 163pp.
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.
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.
- Allen, Gerald
R and Roger Steene. 2002. Indo-Pacific
Coral Reef Field Guide.
Tropical Reef Research. 378pp.
- Edward E.
Ruppert, Richard S. Fox, Robert D. Barnes. 2004.Invertebrate
Brooks/Cole of Thomson Learning Inc., 7th Edition. pp. 963
Jan A., 2005. Biology
of the Invertebrates.
5th edition. McGraw-Hill Book Co., Singapore. 578 pp.