Amphiuma

Amphiuma tridactylum

Amphiuma (two-toed)

One-toed Amphiuma

Musculature of upper and lower Jaw in Amphiuma

Zoomed in and Annotated Amphiuma Lung with Body Orientation

Amphiuma is a genus of aquatic salamanders native to the southeastern United States, known for their eel-like appearance and significant size, making them among the largest of North American salamanders. Members of this genus are commonly referred to as "congo eels" or "amphiumas," although they are not true eels but rather a type of salamander. They are characterized by their elongated bodies, tiny limbs, and a general lack of external gills, with adults relying on lungs for respiration. Amphiumas inhabit slow-moving freshwater environments such as swamps, ponds, and ditches where they lead a primarily nocturnal and secretive lifestyle.

Description

Amphiumas have elongated bodies that can reach lengths of up to 1 meter (3.3 feet) in the case of the Two-toed Amphiuma (Amphiuma means), making it the largest species within the genus. Their bodies are cylindrical, slimy, and dark-colored, aiding in camouflage within their murky aquatic habitats. Despite having four limbs, they are remarkably small, with either one or two toes, which is a distinctive feature used to identify species within this genus. Their eyes are small and lidless, and they possess a lateral line system similar to that of fish, which helps them detect vibrations in the water.

Species

The genus Amphiuma comprises three recognized species:

• Two-toed Amphiuma (Amphiuma means)
• Three-toed Amphiuma (Amphiuma tridactylum)
• One-toed Amphiuma (Amphiuma pholeter)

Each species is distinguished by the number of toes on each limb, which also hints at their adaptive evolution to an aquatic lifestyle.

Habitat and Distribution

Amphiumas are found exclusively in the southeastern United States, particularly in states such as Florida, Alabama, Georgia, and Louisiana. They prefer slow-moving or stagnant freshwater environments, including swamps, marshes, ponds, and ditches. These salamanders are adept at burrowing into mud to escape dry conditions or predators, and they can survive periods of drought by burrowing and entering a state of reduced metabolic activity.

Diet and Behavior

Amphiumas are carnivorous, feeding on a variety of prey including small fish, invertebrates, and other amphibians. They are nocturnal hunters, relying on their ability to sense vibrations and movements in the water to locate prey. Despite their aquatic nature, amphiumas have lungs and must surface periodically to breathe air.

Reproduction

Amphiumas exhibit a unique reproductive strategy among salamanders. They lay large, gelatinous egg masses in water during spring or early summer. The female wraps her body around the eggs to protect them until they hatch, displaying a rare form of parental care among amphibians. The larvae resemble the adults but are smaller and have external gills, which they lose as they mature.

Conservation Status

While amphiumas are not currently listed as endangered, their populations are affected by habitat destruction, pollution, and drainage of wetlands. Conservation efforts are necessary to preserve their habitats and ensure the survival of these unique amphibians.