PHYLUM POGONOPHORAQueency Joy Batucan

Darrienne Maureen Bernabe

POGONOPHORA

Also, known as “Beard Worms”

Completely unknown until the

twentieth century

Tube-dwelling worms found throughout

world’s oceans (at depths between 100

and 4000 m)

All 120 described species are marine

CHARACTERISTICS

Bilaterally symmetrical and vermiform. 

Body has more than two cell layers, tissues and organs. 

Body cavity is a true coelom.  Body possesses no gut, mouth or

anus.  Body possesses 3 separate sections, a

prosoma, a trunk and a opisthosoma. 

CHARACTERISTICS Has a simple nervous system with an

anterior nerve ring and a ventral nerve chord. 

Has a true closed circulatory system.  Has simple respiratory organs.  Reproduction normally sexual and

gonochoristic.  Feed on detritus, or dissolved nutrients,

or through symbiosis with bacteria.  All live in marine environments.

Defining Characteristics

No mouth or digestive tract Organ known as Trophosome filled

with chemoautotrophic mutualistic bacteria

Unsegmented except for rear portion of animal, (or opisthosoma).

Conspicuous red color at ends of plume due to hemoglobin

Body Structure

Divided into four sections: The cephalic lobe The glandular region The trunk And the opisthosoma

The Cephalic Lobe

Consists of a “plume” of one to many thousands of ciliated tentacles

Used for gas exchange, and some nutrient uptake

Also thought to be used to obtain Hydrogen Sulfide

The Glandular Region Contains cells that

secrete chitinous tube Some species contain

“girdle”, (or vestimentum) in this region, which aids in keeping the worm steady in its tube

Normally stand upright and are buried, to about 50% of their length in the substrate

The Trunk The longest part of the

pogonophoran body bears two rows of

papillae (little bumps or warts) along its length

2 regions of ciliation, and 2 girdles of setae (help the animal hold its place within its tube)

The Opisthoma

5 to 30 segments This holdfast is thicker

than the trunk section and is buried in the substrate beyond the end of the animal’s tube.

Modes of Nutrition

Since pogonophora lack a digestive tractmany speculations have been made as tohow they obtain nutrients:

Via tentacles› many believe that some of the smaller species

can obtain dissolved organic matter through their tentacles

Via chemoautotrophic bacteria› The tentacles absorb hydrogen sulfide and

transport it using hemoglobin to the trophosome where it is converted to carbohydrates by the many bacteria that live there

Pogonophora: Phylum or Not?

According to many recent studies involving the sequencing of the elongation factor-1 alpha and developmental studies comparing larvae and basic body plans has grouped the Phylum Pogonophora within the Phylum Annelida.

Now known more accurately as Siboglinidae (a family of polychaete annelids)

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