Parborlasia corrugata explained

Parborlasia corrugatus is a proboscis worm in the family Lineidae. It was formerly placed in family Cerebratulidae. This species of proboscis or ribbon worm can grow to in length, and lives in marine environments down to . This scavenger and predator is widely distributed in cold southern oceans.^[1]

Description

Parborlasia corrugatus is smooth and flat. Adults measure 1-, with a diameter of approximately 2cm (01inches). Specimens can weigh up to . Their colouration is variable, ranging from cream through various tones of black.^{[2] [3]} This worm has a wedge-shaped head containing a cavity filled with fluid. It uses this to fire an adhesive, barbed proboscis as a means of defense, and to capture prey.^[2] This organ has adhesive secretion to aid in securing its meal.

Although this creature does not have a dedicated respiratory system, Parborlasia corrugata is able to obtain oxygen by absorbing it through its skin. An animal of its size would typically find it difficult to receive enough oxygen this way, but this worm has a low metabolic rate, and also enjoys the advantage of its environment, which is cold, oxygen-rich Antarctic waters. When Parborlasia corrugata experiences lower levels of oxygen in the water, it flattens and elongates its body to aid in the uptake of oxygen by increasing its skin area. This manoeuvre also reduces the distance that the oxygen must travel to diffuse into its body.^[2]

Potential predators avoid this species as it has a chemical defense: acidic mucus with a pH 3.5.^[2]

Distribution

This species is found from the intertidal zone to depths of up to . It is found throughout the following areas:

• Antarctica
• Antarctic Peninsula
• south Atlantic Ocean^[4]
• South Shetland Islands
• South Orkney Islands
• South Sandwich Islands
• South Georgia Island
• Bouvet Island
• Kerguelen Island
• Cargados Carajos Shoals in the Indian Ocean
• Falkland Islands
• Tierra del Fuego
• southern Argentina
• Peru
• Chile

Densities range greatly from 0.3 m⁻² recorded in McMurdo Sound, to the substantially higher density of 26.2 m⁻² around Signy Island.

Reproduction

This dioecious species broadcast spawns. The resulting pilidium larvae survive in the water column for up to 150 days.

Diet

Parborlasia corrugatus is both a scavenger and a predator, and feeds upon detritus diatoms, gastropods, amphipods, isopods, various vertebrate carrion, sponges (including Homaxinella balfourensis), jellyfish, seastars, molluscs, anemones, and polychaete worms.

Further reading

• Clarke, A.; Johnston, N.M. (2003). Antarctic marine benthic diversity. Oceanogr. Mar. Biol. Annu. Rev. 41: 47–114
• Biology of the Antarctic Seas XIV, Antarctic Research Series 39(4):289–316, 1983
• Science 245:1484–1486, 1989
• Ecological Monographs 44(1):105–128, 1974
• Antarctic Science 10(4):369–375, 1998
• Clarke A, Prothero-Thomas E (1997) The influence of feeding on oxygen consumption and nitrogen excretion in the Antarctic nemertean Parborlasia corrugatus. Physiological Zoology, 70, 639–649.
• Davison, Bill; Franklin, Craig E. (March 2002). The Antarctic nemertean Parborlasia corrugatus: An example of an extreme oxyconformer. Polar Biology 25(3): 238–240.
• Gibson R (1983) Antarctic nemerteans: the anatomy, distribution, and biology of Parborlasia corrugatus (McIntosh, 1876) (Heter-onemertea, Lineidae). Biology of the Antarctic seas. XIV. Antarctic Research Series, 39, 289–316.
• Heine JN, McClintock JB, Slattery M, Weston J (1991) Energetic composition, biomass, and chemical defense in the common Antarctic nemertean Parborlasia corrugatus McIntosh. Journal of Experimental Marine Biology and Ecology, 153, 15–25.
• Jacob U, Brey T, Arntz WE (January 2006) Towards the trophic structure of the Bouvet Island marine ecosystem. Polar Biology 29(2): 106–113.
• Peck LS (1993) Larval development in the Antarctic nemertean Parbolasia corrugatus (Heteronemertea, Lineidae). Marine Biology, 116, 301–310.
• Rogers AD, Clarke A, Peck LS (1998) Population genetics of the Antarctic heteronemertean Parbolasia corrugatus from the South Orkney Islands. Marine Biology, 131, 1–13.

External links

• Images of Parborlasia corrugatus at Encyclopedia of Life
• Images of Parborlasia corrugatus at WoRMS

Notes and References

1. http://scienceblogs.com/zooillogix/2008/09/giant_antarctic_marine_worm_pa.php Giant Antarctic Marine Worm – Parbolasia Corrugatus : Zooillogix
2. Peter Brueggeman. Nemertina, proboscis worms – Underwater Field Guide to Ross Island & McMurdo Sound, Antarctica
3. Daniel J. Thornhill . Andrew R. Mahon . Jon L. Norenburg . Kenneth M. Halanych . 2008 . Open-ocean barriers to dispersal: a test case with the Antarctic Polar Front and the ribbon worm Parborlasia corrugatus (Nemertea: Lineidae) . Molecular Ecology . 17 . 5104–5117 . 10.1111/j.1365-294X.2008.03970.x . 18992005 . 2010-12-16 . https://web.archive.org/web/20120224070301/http://www.bowdoin.edu/faculty/d/dthornhi/pdf/Thornhilletal2008ME.pdf . 2012-02-24 . dead .
4. http://invertebrates.si.edu/antiz/taxon_view.cfm?ScreenWidth=1440&ScreenHeight=805&taxon=7108&MODE=taxon Antarctic Invertebrates: Parborlasia fueguina