''Amphiuma tridactylum'', the three-toed amphiuma, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of aquatic

salamander Salamanders are a group of amphibians typically characterized by their lizard-like appearance, with slender bodies, blunt snouts, short limbs projecting at right angles to the body, and the presence of a tail in both larvae and adults. All t ...

native to the

Southeastern United States The Southeastern United States, also referred to as the American Southeast or simply the Southeast, is a geographical region of the United States. It is located broadly on the eastern portion of the southern United States and the southern por ...

Description

Amphiuma tridactylum biofluorescence - 41598 2020 59528 Fig2-bottom (cropped)

The three-toed amphiuma looks rather

eel Eels are ray-finned fish belonging to the order Anguilliformes (), which consists of eight suborders, 19 families, 111 genera, and about 800 species. Eels undergo considerable development from the early larval stage to the eventual adult stage ...

-like, with an elongate, dark gray-black, or brown colored body, and tiny

vestigial Vestigiality is the retention, during the process of evolution, of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on co ...

legs. A large salamander, one record sized individual was recorded at 41.25 inches 06 cm. but 18-30 inches 5.7-76 cm.is the typical size of an average adult. They have small, lidless eyes, and

gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

slits. They have four tiny legs each with three toes and an average of 62 costal grooves.

Distribution

The three-toed amphiuma is found in the United States, along the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United ...

states, from

Alabama (We dare defend our rights) , anthem = "Alabama" , image_map = Alabama in United States.svg , seat = Montgomery , LargestCity = Huntsville , LargestCounty = Baldwin County , LargestMetro = Greater Birmingham , area_total_km2 = 135,765 ...

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

, and north to

Missouri Missouri is a state in the Midwestern region of the United States. Ranking 21st in land area, it is bordered by eight states (tied for the most with Tennessee): Iowa to the north, Illinois, Kentucky and Tennessee to the east, Arkansas t ...

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 O ...

Tennessee Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to th ...

and

Kentucky Kentucky ( , ), officially the Commonwealth of Kentucky, is a state in the Southeastern region of the United States and one of the states of the Upper South. It borders Illinois, Indiana, and Ohio to the north; West Virginia and Virginia ...

. Often is found in bottomland marshes and lakes, bayous, cypress sloughs, and streams in hilly regions. Frequently occupies crayfish burrows.

Behavior

Amphiumas are nocturnal

carnivore A carnivore , or meat-eater (Latin, ''caro'', genitive ''carnis'', meaning meat or "flesh" and ''vorare'' meaning "to devour"), is an animal or plant whose food and energy requirements derive from animal tissues (mainly muscle, fat and other s ...

s. They spend most of the time hiding in heavily vegetated areas of permanent bodies of slow moving water, such as swamps, ponds and lakes. They feed on

earthworm An earthworm is a terrestrial invertebrate that belongs to the phylum Annelida. They exhibit a tube-within-a-tube body plan; they are externally segmented with corresponding internal segmentation; and they usually have setae on all segments. T ...

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 ...

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group can ...

s, and other small

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s. Like other amphiumas they are often caught by fishermen who detest them as a nuisance because of their diet that includes just about everything that swims. They mate from December to June then nest from April to October. Unlike other amphiumas, they fertilize internally. About 200 eggs are laid in a single strand that becomes tangled in cavity. They rarely leave the water except after a heavy rainstorm. Males have five sets of cloacal glands, the posterior most set being different in its morphology and histology, that may contribute an ability of the males to court and mate with multiple females in quick succession. This is due to the fact that multiple spermatophores would be produced at the same time, so males wouldn't have to waste extra energy producing another spermatophore after each mating session and consequently create a polygynous dynamic between the individuals.

Biology

The three-toed amphiuma has the largest recorded

erythrocytes Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "holl ...

of any animal measuring 70x40 μm.

References

General reference

* *''Herpetology: An Introductory Biology of Amphibians and Reptiles. 4th Edition.'' Elsevier Inc. 2014. {{Taxonbar, from=Q1258234 Salamandroidea Amphibians of the United States Fauna of the Southeastern United States Endemic fauna of the United States Taxa named by Georges Cuvier Amphibians described in 1827