Scyllaea pelagica

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).

Habi­tat

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).

Re­pro­duc­tion

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).

Be­hav­ior

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

Con­trib­u­tors

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

Glossary

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.

World Map

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.

ectothermic

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.

Ref­er­ences

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.