The two-toed amphiuma (''Amphiuma means'') is an aquatic salamander widely distributed in the southeastern United States. It is commonly, but incorrectly, called "congo snake", "

conger eel ''Conger'' ( ) is a genus of marine congrid eels. It includes some of the largest types of eels, ranging up to 2 m (6 ft) or more in length, in the case of the European conger. Large congers have often been observed by divers during t ...

" or the "blind eel". Two-toed amphiumas are some of the largest extant amphibians in the world.

Description

Two-toed amphiumas can grow from in mass and from in length.Caudata Culture Species Entry – Amphiuma
Caudata.org. Retrieved on 2013-01-03.Deyle, Anna C. (2011
Population Genetics of ''Amphiuma means'' and ''Siren lacertina'' in Central Florida
M.S. Thesis, University of South Florida They have four vestigial legs that end in two toes; the number of toes is one of the primary differences between ''Amphiuma means'' and its relatives, the one-toed and three-toed amphiumas. Additional genetic studies have been conducted on the three species, which indicated genetic distance estimates suggest that there is high levels of similarity between Two-toed amphiumas and three-toed amphiumas, and much greater dissimilarity between the one-toed amphiuma and the two-toed amphiuma The head is pointed and wedge-shaped, and the eyes are small. Adults retain a single gill slit on each side of the head. They are black, dark grey or dark brown in color.

Behavior

Two-toed amphiumas are nocturnal, and are often difficult to handle because of their slippery skins. They may leave water temporarily if weather is wet enough. They dig burrows in muddy stream bottoms, or may invade the burrows of other aquatic creatures. They are primarily found in the littoral zones where fish and crayfish are most abundant and vegetation is floating, on logs, or submerged. They are harmless to humans when left alone, but, when disturbed, they can deliver a tough bite, which may lead to a severe infection. Unlike other salamanders, which are

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, ''A. means'' gives a clear whistle when disturbed. It has been studied that two-toed amphiumas utilize acoustic signals during social interactions for communications at short distances, as the species did not express these acoustics when housed individually. These acoustic signals can be described as "clicks". There are three discernable clicks produced, ranging in frequencies.

Reproduction

Amphiumas breed from June to July in

North Carolina North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia and So ...

and northern

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

. Females lay about 200 eggs in a damp cavity beneath debris, close to standing water, and they remain coiled around them during incubation (which lasts around five months). These eggs are laid in strings.Hatchlings are about long with three pairs of light-colored external gills soon lost after hatching. In some conditions offspring can exhibit direct development and hatch without external gills. In a series of three studies conducted in northern Florida, two-toed amphiuma eggs hatched in response to inundation with water, can stand without feeding for 125 days by using resources from their yolk reserves, and the eggs can retain a period of no growth and still survive after 110 days on a moist substrate. A study depicted seasonal lipid storage increases in males' testicular region and females' liver.

Feeding

Two-toed amphiumas feed on small

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

tadpole A tadpole is the larval stage in the biological life cycle of an amphibian. Most tadpoles are fully aquatic, though some species of amphibians have tadpoles that are terrestrial. Tadpoles have some fish-like features that may not be found i ...

crawfish Crayfish are freshwater crustaceans belonging to the clade Astacidea, which also contains lobsters. In some locations, they are also known as crawfish, craydids, crawdaddies, crawdads, freshwater lobsters, mountain lobsters, rock lobsters, mu ...

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pairs ...

s and insect

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

e. They are also recorded to prey on

reptile Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates (lizards and snakes) and rhynchocephalians ( ...

s and

amphibian Amphibians are tetrapod, four-limbed and ectothermic vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terres ...

s such as southern cricket frogs,

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greater siren The greater siren (''Siren lacertina'') is an eel-like amphibian and one of the three members of the genus ''Siren''. The largest of the sirens and one of the largest amphibians in North America, the greater siren resides in the coastal plains of ...

s, peninsula newts, water snakes of the genus ''

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'' and small

mud turtle ''Kinosternon'' is a genus of small aquatic turtles from the Americas known commonly as mud turtles. Geographic range They are found in the United States, Mexico, Central America, and South America. The greatest species richness is in Mexico, a ...

s. Their hunting behavior is not thoroughly understood, but they are believed to forage actively for food and to wait under debris and in burrows for prey to approach them. They likely detect prey through olfaction.

Habitat and range

Amphiumas live in areas of shallow, heavily vegetated water in swamps,

bayou In usage in the Southern United States, a bayou () is a body of water typically found in a flat, low-lying area. It may refer to an extremely slow-moving stream, river (often with a poorly defined shoreline), marshy lake, wetland, or creek. They ...

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

s, and

pond A pond is an area filled with water, either natural or artificial, that is smaller than a lake. Defining them to be less than in area, less than deep, and with less than 30% emergent vegetation helps in distinguishing their ecology from th ...

s, as well as

wet prairie Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the ...

s. It has been found that their microhabitats largely coincide with high prey availability. Their range includes southeastern

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...

, eastern

South Carolina )''Animis opibusque parati'' ( for, , Latin, Prepared in mind and resources, links=no) , anthem = " Carolina";" South Carolina On My Mind" , Former = Province of South Carolina , seat = Columbia , LargestCity = Charleston , LargestMetro = ...

, southern

Georgia Georgia most commonly refers to: * Georgia (country), a country in the Caucasus region of Eurasia * Georgia (U.S. state), a state in the Southeast United States Georgia may also refer to: Places Historical states and entities * Related to the ...

and

Alabama (We dare defend our rights) , anthem = "Alabama (state song), Alabama" , image_map = Alabama in United States.svg , seat = Montgomery, Alabama, Montgomery , LargestCity = Huntsville, Alabama, Huntsville , LargestCounty = Baldwin County, Al ...

, south

Mississippi Mississippi () is a state in the Southeastern region of the United States, bordered to the north by Tennessee; to the east by Alabama; to the south by the Gulf of Mexico; to the southwest by Louisiana; and to the northwest by Arkansas. Miss ...

Arkansas Arkansas ( ) is a landlocked state in the South Central United States. It is bordered by Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, and Texas and Oklahoma to the west. Its name is from the Osage ...

Louisiana Louisiana , group=pronunciation (French: ''La Louisiane'') is a state in the Deep South and South Central regions of the United States. It is the 20th-smallest by area and the 25th most populous of the 50 U.S. states. Louisiana is borde ...

, and southeastern

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

References

{{Taxonbar, from=Q243813 Salamandroidea Extant Pleistocene first appearances Fauna of the Southeastern United States Amphibians of the United States Amphibians described in 1821