Remipedes: Remipedia

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REMIPEDES: Remipedia

NO COMMON NAME (Speleonectes gironensis): SPECIES ACCOUNT

PHYSICAL CHARACTERISTICS

Remipedes (REM-mih-peeds) are wormlike crustaceans that lack both color and eyes and measure 0.35 to 1.8 inches (9 to 45 millimeters) long. They have a short, distinct head and, depending on species, a long body trunk with 10 to 32 segments. Most of the trunk segments have a pair of flattened, paddlelike limbs directed out from the sides. The head has a pair of thread-like sensory processors and two pairs of antennae. The second pair of antennae is long and feathery.

The mouthparts are found inside the head. They include three pairs of jawlike appendages: a pair of mandibles (MAN-dih-bulz), or biting mouthparts, and two pairs of maxillae (mack-SIH-lee). The first pair of maxillae is tipped with fanglike projections. The fangs inject an unknown chemical that paralyzes and kills prey. The second pair of maxillae is followed by a nearly identical pair of mouthparts called maxillipeds (mack-SIH-leh-pehds). The fingerlike maxillipeds are actually attached to the first trunk segment, which is tightly joined to the head.

GEOGRAPHIC RANGE

Remipedes are found in underwater sea caves along the shores of the Bahamas, Canary Islands, Cuba, eastern Mexico, northwestern Australia, and the Indian Ocean.

HABITAT

Remipedes live only in completely submerged sea caves near the shores of islands and some continents. They live with other cave-dwelling, or troglodytic (TRAH-gloh-DIH-tik), crustaceans and fish.

DIET

They are predators and eat troglodytic shrimp and fish. Remipedes are closely associated with the sand or mud at the bottom of caves. In captivity they gather these materials into a small ball, hold it over their mouth, then eat it. Some scientists think that they are using bacteria in the sediment as either a food source or for some physiological purpose.

BEHAVIOR AND REPRODUCTION

Remipedes usually swim upside down in open water inside caves. They are sometimes found swimming, resting, or grooming on the bottom. The antennae are cleaned by drawing them through the trunk limbs, while the trunk limbs are cleaned with the mouthparts.

Remipedes are hermaphrodites (her-MAE-fro-daits), with individuals having the reproductive organs of both males and females. The egg-producing organs, or ovaries (OH-veh-reez), are located in the head. The tubes or ducts leading from the ovaries to the outside of the body open in the trunk segment that has the seventh pair of trunk limbs. The male reproductive organs open at the fourteenth pair of trunk limbs. The males produce sperm packets. Very little is known about how remipedes develop, other than the juveniles resemble the adults and have fewer trunk segments.

REMIPEDES AND PEOPLE

Remipedes do not have any immediate impact on humans or their activities.

SWIMMING TO THEIR OWN BEAT

Remipedes have puzzled scientists since their discovery in a cave in the Bahama Islands in 1980. Their wormlike bodies and other features are considered primitive and similar to those of the ancestors of all crustaceans. Yet their internal and venom-injecting mouthparts and trunk limbs directed sideways from the body are recognized as unique features among crustaceans. They swim about on their backs in caves by rhythmically beating these paddlelike limbs.

CONSERVATION STATUS

No remipedes are considered endangered or threatened. However, one species, Speleonectes lucayensis, is protected by Lucayan National Park on Grand Bahama Island. The cave habitats of all remipedes are threatened by logging, development, pesticides, and sewage disposal.

NO COMMON NAME (Speleonectes gironensis): SPECIES ACCOUNT

Physical characteristics: Speleonectes gironensis measure up to 0.55 inches (14 millimeters) in length. The maximum number of trunk segments is 25. The last pair of appendages on the end of the body trunk is twice as long as the last body trunk segments.

Geographic range: Speleonectes gironensis (abbreviated to S. gironensis) are found only in the undersea caves along the coast of Matanzas and Holguin Provinces, Cuba.

Habitat: S. gironensis are found in caves from 39 feet (12 meters) and deeper.

Diet: They eat mostly small cave crustaceans.

Behavior and reproduction: They swim in open water. Nothing is known about their reproductive behavior.

Speleonectes gironensis and people: This species does not impact humans or their activities.

Conservation status: This species is not considered endangered or threatened. ∎

FOR MORE INFORMATION

Books:

Yager, Jill. "The Reproductive Biology of Two Species of Remipedes." In Crustacean Sexual Biology, edited by R. T. Bauer and J. W. Martin. New York: Columbia University Press, 1991.

Periodicals:

Yager, J. "Remipedia, a New Class of Crustacea from a Marine Cave in the Bahamas." Journal of Crustacean Biology 1 (1981): 328-333.

Yager, J. "Speleonectes gironensis, New Species (Remipedia: Speleonectidae), from Anchialine Caves in Cuba, with Remarks on Biogeography and Ecology." Journal of Crustacean Biology 14 (1994): 752-762.

Yager, J., and W. F. Humphreys. " Lasionectes exleyi, sp. nov., the First Remipede Crustacean Recorded from Australia and the Indian Ocean, with a Key to the World Species." Invertebrate Taxonomy 10 (1996): 171-187.