Interesting information: New Discovery!
Monterey Bay Aquarium Research Institute biologist Karen Osborn and her co-workers recently discovered a holopelagic member of Chaetopterid worms- Chaetopterus pugaporcinus (Halanych et al. 2007). They found the species in a marine environment around Monterey Bay, California. Osborn and her colleagues were unsure of the organism because they resembled the larva of Chaetopterus but also had adult features. They have considered the possibility that the organisms were larva despite them being recognizably larger than polychaete larvae (Halanych et al. 2007). After using DNA analysis and creating the first family tree of 12 Chaetopterus species, Osborn and researchers found that the organism was most closely related to Chaetopterus (Osborn et al. 2007).
According to the Monterey Bay Auqarium Research Institute, to understand more about the new worms, the researchers combined these modern analytical techniques with the time-honored biological approach of making direct, meticulous observation of live animals in their native environment and of dissected animals in the laboratory (MBARI). Osborn and those working with her noticed that the worms stayed consistenly around 1200 meters. 'The worms seemed to hang out in this particular depth range even when the seafloor itself was thousands of meters deeper (MBARI).'
The Latin species name, Chaetopterus pugaporcinus, translates to ‘rump of the pig’ because it resembles a pair of buttocks (Osborn et al. 2007).
Importance to Deep Sea Biology
Researches are still uncertain whether the C. pugaporcinus they have been studying are larvae or adults (MBARI). Interestingly, none of the worms had identifiable sex organs, eggs, or sperm to help indicate the age or sex (MBARI). “Resemblance to a larval form and the absence of some adult features such as dorsal-ventral flattening of the anterior region and the absence of modified chaetae on the anterior segment suggest paedomorphosis during the evolution of this lineage (Halanych et al. 2007).” This is important to deep- sea biology because it shows genetic diversity, evolution, and encourages the continuing study and findings of deep-sea organisms, specifically annelids.
Like other polychaetes, the worm has a segmented body but with an inflated middle segment. The inflated mid section along with the compression of the posterior and anterior segments give the worm a round shape (Osborn et al. 2007). The benthic worm has no eyes, no stout, modified chaeta, cilia present in the midsection and is ‘semitransparent white to beige with dark brown to purple pigment lining the interior of the buccal region (Osborn et al. 2007).’
Distribution and Feeding
Osborn and her colleagues recently found the species between 900-1200 meters below the surface of the ocean with the seafloor being 3500 meters deep (Osborn et al. 2007). The only place they have currently been found is near Monterey Bay, California. Researchers believe the species drift below the oxygen minimum zone for their food. The worms move downward with their mouths open, surrounded by a cloud of mucus (MBARI). The mucus is secreted from the inner notopodia and moves inward toward the body (Macginitie). This mucus allows them to trap and feed off the remains of dead organisms and fecal.
Halanych, K.M., L.N. Cox, T.H. Struck. 2007. A brief review of holopelagic
annelids. Integrate and Comparative Biology. 47(6):872-879
Macginitie, G.E. 1939. The Method of Feeding of Chaetopterus. Biological
Monterey Bay Aquarium Research Institute.
February 5, 2015
Osborn, K.J., G.W. Rouse, S.K. Goffredi, and B.H. Robison. 2007. Description
and relationships of Chaetopterus pugaporcinus, an unusual pelagic
polychaete. The Biological Bulletin 212:40-54