Parborlasia corrugatus

Parborlasia corrugatus
Parborlasia corrugatus from the Ross Sea
Scientific classification
Kingdom:	Animalia
Subkingdom:	Eumetazoa
Superphylum:	Lophotrochozoa
Phylum:	Nemertea
Class:	Anopla
Order:	Heteronemertea
Family:	Cerebratulidae
Genus:	Parborlasia
Species:	P. corrugatus
Binomial name
Parborlasia corrugatus (McIntosh, 1876)
Synonyms
Cerebratulus charcoti Cerebratulus corrugatus Cerebratulus hanseni Cerebratulus magelhaensicus Cerebratulus steeneni Cerebratulus steineni Cerebratulus steinini Cerebratulus subtilis Lineus corrugatus

Parborlasia corrugatus is a proboscis worm in the family Cerebratulidae.^[1] This species of proboscis or ribbon worm can grow to 2 metres (6 ft 7 in) in length, and lives primarily in marine environments down to 4,000 metres (13,000 ft). It is a widely distributed scavenger and predator.

Description

Parborlasia corrugatus is smooth and flat. Adults measure 1–2 metres (3 ft 3 in–6 ft 7 in), with a diametre of approximately 2 cm (0.79 in). Specimens can weigh up to 140 grams (4.9 oz). 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.

Body wall structure (after McIntosh, 1876)

Although this creature does not have a dedicated respiratory system, Parborlasia corrugatus 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 the cold Antarctic waters which are rich in oxygen. When Parborlasia corrugatus 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 manoevre 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

Anatomy of Parborlasia corrugatus (fig. 17 and 18 only)

This species is found from the intertidal zone to depths of up to 3,950 metres. It is found throughout the following areas:^[2]

• Antarctica
• Antarctic Peninsula
• south Atlantic Ocean^[4]
• South Shetland Islands (62°00′S 58°00′W / 62°S 58°W / -62; -58 (South Shetland Islands))
• South Orkney Islands (60°35′S 45°30′W / 60.583°S 45.5°W / -60.583; -45.5 (South Orkney Islands))
• South Sandwich Islands (57°45′S 26°30′W / 57.75°S 26.5°W / -57.75; -26.5 (South Sandwich Islands))
• South Georgia Island (54°15′S 36°45′W / 54.25°S 36.75°W / -54.25; -36.75 (South Georgia Island))
• Bouvet Island (54°26′S 03°24′E / 54.433°S 3.4°E / -54.433; 3.4 (Bouvet Island))
• Kerguelen Island (49°15′S 69°35′E / 49.25°S 69.583°E / -49.25; 69.583 (Kerguelen Islands))
• Cargados Carajos Shoals in the Indian Ocean
• Falkland Islands
• Tierra del Fuego (54°00′S 70°00′W / 54°S 70°W / -54; -70 (Tierra del Fuego))
• southern Argentina
• Peru
• Chile

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Densities range greatly from 0.3 m⁻² recorded in McMurdo Sound, to the substantially higher densitiy of 26.2 m⁻² around Signy Island.^[3]

Reproduction

This dioecious species broadcasts spawn. The resulting pilidium larvae survive in the water column for up to 150 days.^[3]

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.^[2][3]

References

1. ^ Giant Antarctic Marine Worm – Parbolasia Corrugatus : Zooillogix
2. ^ ^{a b c d e f} Peter Brueggeman. Nemertina, proboscis worms – Underwater Field Guide to Ross Island & McMurdo Sound, Antarctica
3. ^ ^{a b c d} 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. doi:10.1111/j.1365-294X.2008.03970.x. https://www.bowdoin.edu/faculty/d/dthornhi/pdf/Thornhilletal2008ME.pdf/. 
4. ^ Antarctic Invertebrates: Parborlasia fueguina

Further reading

• Clarke, A.; Johnston, N.M. (2003). Antarctic marine benthic diversity. Oceanogr. Mar. Biol. Ann. 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
• Journal of Experimental Marine Biology and Ecology 153(1):15–25, 1991
• Antarctic Science 10(4):369–375, 1998
• Polar Biology 25(3):238–240, 2002
• Polar Biology 29(2):106–113, 2006
• 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.
• 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.
• 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