AMERICAN TAILED CAECILIANS: Rhinatrematidae

PHYSICAL CHARACTERISTICS

American tailed caecilians (sih-SILL-yuhns) are medium-sized caecilians with a true, but short, tail. There are a few vertebrae (VER-teh-bree), or the bones that make up the spinal column, behind the cloaca, and these are considered a true tail. The cloaca (kloh-AY-kuh) is the chamber in some animals that holds waste from the kidneys and intestines, holds eggs or sperm about to be released to the outside, holds sperm entering a female's body, and is the passage through which young are born.

Caecilians look like earthworms. A series of rings runs the length of the body starting just behind the head. The rings are inside the body and attached to the vertebrae. American tailed caecilians have three rings per vertebra (VER-teh-bruh, the singular of vertebrae). The skin is folded over the rings, making grooves between the rings. The second and third sets of rings make shallower grooves than the main set.

The mouth of American tailed caecilians opens at the front of the head, and the upper and lower jaws are the same length. The jaws have a dual-action mechanism, like a seesaw. The tentacle openings in these caecilians are next to their eyes. American tailed caecilians are either purplish gray or gray with yellowish stripes along the sides of the body. Adult American tailed caecilians are 8 to 13 inches (20 to 33 centimeters) long.

GEOGRAPHIC RANGE

American tailed caecilians live in northern South America, including parts of Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Surinam, and Venezuela.

HABITAT

American tailed caecilians live in tropical rainforests in moist spots full of leaf litter, rotten logs, and burrows in the soil. The larvae live mainly in streams. Larvae (LAR-vee) are animals in an early stage that change body form in a process called metamorphosis (MEH-tuh-MORE-feh-sis) before becoming adults.

DIET

Scientists are not sure what American tailed caecilians eat. They have found large amounts of soil in the intestines of these animals, which is evidence that they eat earthworms. Undigested earthworms and the remains of insects also have been found inside caecilians.

BEHAVIOR AND REPRODUCTION

American tailed caecilians burrow in soil and leaf litter. They sometimes twist their bodies rapidly when subduing prey they have grasped in their mouths. Scientists do not know how American tailed caecilians reproduce. They believe that most species lay eggs and that the females coil around the eggs to protect them. Larvae of one species have been found.

AMERICAN TAILED CAECILIANS AND PEOPLE

American tailed caecilians have no known importance to people.

CONSERVATION STATUS

American tailed caecilians are not considered threatened or endangered. Although not threatened according to the World Conservation Union (IUCN), caecilians are rarely found. Scientists are not sure whether this is because these animals are rare or because they are highly secretive and difficult to find.

MARBLED CAECILIAN (Epicrionops marmoratus): SPECIES ACCOUNT

Physical characteristics: Marbled caecilians reach a length of about 12 inches (30 centimeters). They have a stocky build, and the tail is about 1 inch (2.5 centimeters) long. The back is dark purple with scattered yellowish blotches. The sides and belly are yellow with scattered dark purple spots.

Geographic range: Marbled caecilians live on the Pacific slope of Ecuador.

Habitat: Marbled caecilians live in rainforests. They also live along streams in areas that have been cleared of trees.

Diet: Marbled caecilians probably eat earthworms and small insects and crustaceans. Crustaceans (krus-TAY-shuns), such as crayfish, are water-dwelling animals that have jointed legs and a hard shell but no backbone.

Behavior and reproduction: In captivity marbled caecilians dig their own burrows in moist soil. They find earthworms and crickets by scent and lunge forward to grasp them in their jaws. To eat larger earthworms, which struggle when caught, marbled caecilians grasp the worm in their mouth and then rapidly spin around to break the worm in half. The caecilian then swallows the grasped part of the worm. Crocodiles and alligators use the same method to subdue and rip apart their prey.

Scientists are not sure how marbled caecilians reproduce. Larvae of this species have been found in leaf litter and stone rubble on the bottoms of small streams. This finding is evidence that marbled caecilians are an egg-laying species.

Marbled caecilians and people: Marbled caecilians have no known importance to people.

Conservation status: Marbled caecilians are not considered threatened or endangered. ∎

FOR MORE INFORMATION

Books:

Lamar, William W. The World's Most Spectacular Reptiles and Amphibians. Tampa, FL: World, 1997.

Lawlor, Elizabeth P. Discover Nature in Water and Wetlands. Mechanicsburg, PA: Stackpole, 2000.

Llamas Ruiz, Andres. Reptiles and Amphibians: Birth and Growth. New York: Sterling, 1996.

Petranka, J. W. Salamanders of the United States and Canada. Washington, DC: Smithsonian Institution Press, 1998.

Web sites:

"Caecilian." Animal Bytes.http://www.sandiegozoo.org/animalbytes/t-caecilian.html (accessed on April 11, 2005).

Hawes, Alex. "On Waterdogs, Mudpuppies, and the Occasional Hellbender." Zoogoer.http://nationalzoo.si.edu/Publications/ZooGoer/2000/2/waterdogsmudpuppieshellbender.cfm (accessed on April 11, 2005).

Summers, Adam. "Squeeze Play." Natural History.http://biomechanics.bio.uci.edu/_html/nh_biomech/caecilian/caecilian.htm (accessed on April 11, 2005).