Pogonophora represents a group of segmented worms living in chitinous tubes, largely restricted to deep-sea environments such as methane seeps and hydrothermal vents. They are unusual in lacking a mouth and anus as adults, and in having the gut tissue massively expanded and filled with symbiotic bacteria, through which they gain their nutritional requirements.
Keywords: annelida; hydrothermal vents; symbiosis; chemoautotrophic bacteria





