Scyllaea pelagica

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Geographic Range

Although the range of S. pelagica does cover much of the Atlantic ocean, it is usually found in warmer waters. More specifically, S. pelagica is most common in the Gulf of Mexico (Fatheringham and Brunmeister 1989).


Pelagic: As stated above, S. pelagica spends almost all of its life grazing in patches of drifting sea weed, more specifically Sargassum weed. S. pelagica mimics its environment, the Sargassum sea weeds, very accurately. The leaf-like lobes along its back, and its specific coloration make it almost impossible to spot when floating in a patch of Sargassum. This is a form of camoflauge that is very successful in deceiving pradators.

Physical Description

The nudibranch, S. pelagica, is often called a sea slug. The shell and the mantle cavity have been completely lost, and only secondary gills are present (Mill 1972). They are bilaterally symmetrical and have two pairs of sensory organs (tentacles) near the head, an anterior pair of cephalic tentacles, and a posterior ring of tentacles. These tentacles don't aid in capturing prey, but are sensory organs or aid in respiration. They resemble leaf-like lobes, a form of cryptology in their environment. S. pelagica is orange-brown and yellow in color, and is about 3 to 4 inches (7-10 cm) in length (Fatheringham and Brunemeister 1989).


S. pelagica is hermaphroditic, but cross-fertilizes through reciprocal copulation. Fertilization is internal. Characteristic of nudibranchs, the larva of S. pelagica pass through a planktonic trochophore-like stage (Kaestner 1967).


There is little information on specific behavior of S. pelagica, except that it spends most of its life grazing for food in drifting patches of sea weed.

Food Habits

S. pelagica is carnivorous. It usually feeds on hydroids that are living in the same Sargassum weed in which it makes its home. S. pelagica does not hunt its prey in the traditional sense, but simply floats or grazes in its particular patch of sea weeds (Hickman 1973).

Economic Importance for Humans: Positive

S. pelagica, along with almost all nudibranchs, are of very little economic importance to humans. There is virtually no market for nudibranchs to be used economically existing in the world today (Morris 1980).

Conservation Status


Gabriel Vaughn (author), Southwestern University, Stephanie Fabritius (editor), Southwestern University.


Atlantic Ocean

the body of water between Africa, Europe, the southern ocean (above 60 degrees south latitude), and the western hemisphere. It is the second largest ocean in the world after the Pacific Ocean.

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bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.


animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

native range

the area in which the animal is naturally found, the region in which it is endemic.


Fatheringham, N., S. Brunemeister. 1989. Beachcombers's Guide to Gulf Coast Marine Life: Florida, Alabama, Mississippi, Louisiana, Texas. Houston: Gulf Publishing, Co..

Hickman, C. 1973. Biology of Invertebrates. St. Louis: The C.U. Mosby Company.

Kaestner, A. 1967. Invertebrate Zoology, vol. 1. New York: John Wiley & Son, Inc..

Mill, P. 1972. Respiration in the Invertebrates. London: Macmillan.

Morris, R. 1980. Intertidal Invertebrates of California. Stanford: Stanford University Press.