1. Picture from http://www.cyhaus.com/marine/Worms.htm
Phylum Pogonophora
Picture from

2. Pogonophora Also, known as “Beard Worms”
Completely unknown until the twentieth century
Tube-dwelling worms found throughout world’s oceans
All 120 described species are marine

3. Attributes Size- 5cm-1.5m long and 1mm –4cm in diameter
Gonochoristic (having 2 distinct sexes)
Closed circulatory system with heart
Small brain with ventral nerve cord
Protostomic development
Picture taken from

4. 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

5. Life Style Sessile, living in long chitinous tubes
Extends plume (anterior end) outward to obtain some nutrition and function in gas exchange
Most found at depths of 200 meters and up
Most often found by deep-sea hydrothermal vents, rifts and cold-water seeps

6. Body Structure Divided into four sections: The cephalic lobe
The glandular region
The trunk
And the opisthosoma
Picture from

7. 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
Picture taken from

8. 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
Picture taken from

9. The Trunk The longest part of the pogonophoran body
Contains a pair of uninterrupted coelomic cavities
Bears a number of papillae, 2 regions of ciliation, and 2 girdles of setae
Contains organs and gonads
Picture taken from

10. The Opisthoma Displays conspicuous segmentation
Contains 5-30 segments isolated by septa
Used to anchor worm in tube
Not discovered as part of body until 1965, since it is generally buried in sediment

11. Modes of Nutrition
Since pogonophora lack a digestive tract many speculations have been made as to how 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

12. Interesting Facts
Recent research shows that pogonophora contain three types of hemoglobin
This hemoglobin can simultaneously and reversibly bind to oxygen and sulfide at two different sites
Thus the hemoglobin protects the animal tissues from sulfide toxicity by binding to sulfide with a higher affinity than cytochrome c oxidase, which is responsible for the toxic effects

13. Pogonophora: Phylum or Not?
With recent discoveries in DNA sequencing, the classification of Pogonophora as its own phylum has come into question.
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.