NEMERTEAN WORMFeatured in the "Creatures of the Deep" episode of Life.
 More LifeNemertean worms are known by many names, including bootlace, proboscis and ribbon worms. That's because Nemertea is actually a phylum that encompasses about 900 species of worms, some of which are quite plentiful in the world's oceans and quite lengthy, too. Nemerteans regularly grow to lengths of 10 feet (3 meters) or longer.
One species of nemertean worm, Lineus longissimus, found in European waters, has been known to reach close to 100 feet (30 meters). Some researchers speculate that the worms could, when fully extended, reach twice that length, placing them among the planet's longest living organisms. But it can be difficult to measure these creatures precisely in the wild, as they tend to contract significantly when bothered.
They live everywhere, from shallow tidal regions to deepwater trenches. Occasionally, they'll live in freshwater habitats or even on land. Despite their abundance, humans have much to discover about these long, delicate creatures. Still, we do know a little about their remarkable biology.
HIGHLY DEVELOPED WORMS
Unlike some of their fellow worms, nemerteans are quite developed anatomically, with a sophisticated blood-circulatory system, nervous system and digestive system that includes a gut and anus. Some of them have cilia (small, protuberant, tubelike formations) along their skin. Cilia may help some nemertean worms move, while others get around by flexing and contracting their muscles.
Nemerteans are carnivorous and open to eating almost anything that they come across, living or dead, including small invertebrates and even eggs. In Life, a huge collection of nemertean worms, sea stars, urchins and other creatures stumble across a seal pup carcass — a rare bounty. The worms' sharp, barb-laden snouts, allow them to stab through the seal's skin, gaining access to the precious flesh inside.
SURVIVORS
Like some types of lizards, nemerteans can often survive even after part of their body breaks off. That ability becomes useful for reproduction, as many nemerteans reproduce asexually: A piece of a nemertean worm can regenerate and become an independent, full-grown worm.
Written by Jacob Silverman, HowStuffWorks
|
advertisement
More Life
Stay Connected
Own Life
|
-
our sites
-
video
mobile
-
shop
-
stay connected
-
corporate
