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Pogonophorans
Deep Sea Tube Worms
In 1900, a strange tube-dwelling worm
was dredged from deep waters around
Indonesia. While somewhat resembling
tube-dwelling it lacked obvious
segmentation; even more strangely, it also
lacked a mouth, gut, or anus.
The name Pogonophora is Greek for
"beard-bearers,“
comes from the fact that many species
have from one to many tentacles at the
anterior end.
The not well known anatomy of
pogonophorans was interpreted to show
that pogonophorans were chordate
relatives
Lower half of the body is segmented not
the top half
They have no digestive system in the deep
sea versions
1)Bilaterally symmetrical and vermiform.
2)Body has more than two cell layers,
tissues and organs.
3)Body cavity is a true coelom.
4)Body possesses no gut, mouth or anus.
5)Body possesses 3 separte sections, a
prosoma, a trunk and a opisthosoma.
6)Has a simple nervous system with an
anterior nerve ring and a ventral nerve
chord.
7)Has a true closed circulatory system.
8)Has simple respiratory organs.
9)Reproduction normally sexual and
gonochoristic.
10)Feed on detritus, or dissolved nutrients,
or through symbiosis with bacteria.
11)All live in marine environments.
This was the first discovery of the
Pogonophora, an animal phylum restricted
to the deep sea and remarkably common
in certain habitats there. About 80
pogonophoran species are known today,
with new species still being discovered.
One of the most spectacular zoological
discoveries of recent years was the finding
in 1977 of giant pogonophoran worms, 1.5
meters long, growing in heated, sulfur-rich
water around warm-water vents in the
Pacific Ocean, 2600 meters below the
surface (pictured at right).
These worms are sometimes placed in
their own phylum, the Vestimentifera, but
they are similar to pogonophorans in most
respects, and the current tendency is to
group these rift-dwelling worms together
with the rest of the Pogonophora into one
phylum.