Species of ribbon worm
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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.
Description.
"Parborlasia corrugatus" is smooth and flat. Adults measure , with a diameter of approximately . Specimens can weigh up to . Their colouration is variable, ranging from cream through various tones of black. 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. 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.
Potential predators avoid this species as it has a chemical defense: acidic mucus with a pH 3.5.
Distribution.
This species is found from the intertidal zone to depths of up to . It is found throughout the following areas:
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.
References.
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