Two-toed amphiuma

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Two-toed amphiuma
Temporal range: Pleistocene - present
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Amphiuma (two-toed).jpg
Status TNC G5.svg
Secure  (NatureServe) [3]
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Urodela
Family: Amphiumidae
Genus: Amphiuma
Species:
A. means
Binomial name
Amphiuma means
Garden in Smith, 1821

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" or the "blind eel".

Contents

Description

Two-toed amphiumas are the most prominent in the Amphiumidae family and the longest salamander species in the United States, [4] that can grow from 39 to 1,042 g (1.4 to 36.8 oz) in mass and from 34.8 to 116 cm (13.7 to 45.7 in) in length. [5] [6] [7] 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; 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. [8] 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. [6] Two-toed amphiumas tend to be unicolored. Their dark dorsum contrasts with their slightly lighter ventrum. [4]

Distribution and habitat

Amphiumas live in areas of shallow, heavily vegetated water in swamps, bayous, lakes, and ponds, as well as wet prairies. [9] They tend to be found below the fall line but occasionally in low sandy pine hills. [4] It has been found that their microhabitats largely coincide with high prey availability. [10] They require a habitat with light soil, so they can burrow in it. [4] Their range includes southeastern Virginia, eastern North Carolina, South Carolina, southern Georgia and Alabama, Florida, south Mississippi, Arkansas, Louisiana, and southeastern Texas. [11]

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. [12]

They are harmless to humans when left alone, but, when disturbed, they can deliver a tough bite, which may lead to a severe infection. A. means gives a clear whistle when disturbed.[ citation needed ] 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. [13] These acoustic signals can be described as "clicks". There are three discernable clicks produced, ranging in frequencies. [5]

Breeding

Amphiumas breed from June to July in North Carolina and northern Florida. 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. [14] Hatchlings are about 2 in (51 mm) long with three pairs of light-colored external gills soon lost after hatching. [9] In some conditions offspring can exhibit direct development and hatch without external gills. [14] 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. [15]

A study depicted seasonal lipid storage increases in males' testicular region and females' liver. [7]

Diet

Two-toed amphiumas feed on small fish, tadpoles, crawfish, insects and insect larvae. They are also recorded to prey on reptiles and amphibians such as southern cricket frogs, southern leopard frogs, greater sirens, peninsula newts, water snakes of the genus Nerodia and small mud turtles. When feeding, they have two types of suction feeding: buccal expansion with no forward movement of the head for small prey and buccal expansion with a rapid strike, sharp teeth, and rapid twisting to subdue larger prey. [16] 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. [9]

Related Research Articles

<span class="mw-page-title-main">Amphibian</span> Class of ectothermic tetrapods

Amphibians are ectothermic, anamniotic, four-limbed vertebrate animals that constitute the class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all tetrapods excluding the amniotes. All extant (living) amphibians belong to the monophyletic subclass Lissamphibia, with three living orders: Anura, Urodela (salamanders), and Gymnophiona (caecilians). Evolved to be mostly semiaquatic, amphibians have adapted to inhabit a wide variety of habitats, with most species living in freshwater, wetland or terrestrial ecosystems. Their life cycle typically starts out as aquatic larvae with gills known as tadpoles, but some species have developed behavioural adaptations to bypass this.

<span class="mw-page-title-main">Salamander</span> Order of amphibians

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 ten extant salamander families are grouped together under the order Urodela from the group Caudata. Urodela is a scientific Latin term based on the Ancient Greek οὐρά δήλη: ourà dēlē "conspicuous tail". Caudata is the Latin for "tailed ones", from cauda: "tail".

<i>Amphiuma</i> Genus of amphibians

Amphiuma is a genus of aquatic salamanders from the United States, the only extant genus within the family Amphiumidae. They are colloquially known as amphiumas. They are also known to fishermen as "conger eels" or "Congo snakes", which are zoologically incorrect designations or misnomers, since amphiumas are actually salamanders, and not fish, nor reptiles and are not from Congo. Amphiuma exhibits one of the largest complements of DNA in the living world, around 25 times more than a human.

<span class="mw-page-title-main">Spotted salamander</span> Species of amphibian

The spotted salamander or yellow-spotted salamander is a mole salamander common in eastern United States and Canada. It is the state amphibian of Ohio and South Carolina. The species ranges from Nova Scotia, to Lake Superior, to southern Georgia and Texas. Its embryos have been found to have symbiotic algae living in and around them, the only known example of vertebrate cells hosting an endosymbiont microbe.

<span class="mw-page-title-main">Sirenidae</span> Family of amphibians

Sirenidae, the sirens, are a family of neotenic aquatic salamanders. Family members have very small fore limbs and lack hind limbs altogether. In one species, the skeleton in their fore limbs is made of only cartilage. In contrast to most other salamanders, they have external gills bunched together on the neck in both larval and adult states. Sirens are found only in the Southeastern United States and northern Mexico.

<span class="mw-page-title-main">Greater siren</span> Species of amphibian

The greater siren is an amphibian and one of the five 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 the southeastern United States.

<i>Necturus</i> Genus of amphibians

Necturus is a genus of aquatic salamanders in the family Proteidae. Species of the genus are native to the eastern United States and Canada. They are commonly known as waterdogs and mudpuppies. The common mudpuppy (N. maculosus) is probably the best-known species – as an amphibian with gill slits, it is often dissected in comparative anatomy classes. The common mudpuppy has the largest distribution of any fully aquatic salamander in North America.

<i>Amphiuma tridactylum</i> Species of amphibian

Amphiuma tridactylum, the three-toed amphiuma, is a species of aquatic salamander native to the Southeastern United States.

<span class="mw-page-title-main">Lesser siren</span> Species of amphibian

The lesser siren is a species of aquatic salamander native to the eastern United States and northern Mexico. They are referred to by numerous common names, including two-legged eel, dwarf siren, and mud eel. The specific epithet intermedia denotes their intermediate size, between the greater siren, Siren lacertina, and the dwarf sirens, Pseudobranchus species.

<span class="mw-page-title-main">Northern slimy salamander</span> Species of amphibian

The northern slimy salamander is a species of terrestrial plethodontid salamander found throughout much of the eastern two-thirds of the United States.

<span class="mw-page-title-main">Southern dwarf siren</span> Species of amphibian

The southern dwarf siren, is a perennibranch salamander lacking hind legs. Found exclusively in Florida, it is one of two currently recognized species of dwarf sirens. Two subspecies are currently recognized; P. a. axanthus, the narrow-striped dwarf siren, and P. a. belli, the Everglades dwarf siren.

<i>Amphiuma pholeter</i> Species of amphibian

The one-toed amphiuma is an aquatic, eel-like salamander native to the southeastern United States. It was unknown to science until 1950, when it was collected by herpetologist W. T. Neill. It is rarely observed in the wild, and much about the species remains uncertain.

<i>Bolitoglossa</i> Genus of amphibians

Bolitoglossa is a genus of lungless salamanders, also called mushroom-tongued salamanders, tropical climbing salamanders, or web-footed salamanders, in the family Plethodontidae. Their range is between northern Mexico through Central America to Colombia, Venezuela, Ecuador, Peru, northeastern Brazil, and central Bolivia. Neotropical salamanders of the Bolitoglossa make up the largest genus in the order Caudata, consisting of approximately one-fifth of all known species of salamanders. Adult salamanders range anywhere from 45mm to 200mm in length depending on their specific species. They are notorious for their ability to project their tongue at prey items, as indicated from their name. They are also known for their webbed feet, having significantly more webbing than any other species outside their genus with the exception of the cave-dwelling Mexican bolitoglossine Chiropterotriton magnipes. Although webbed feet are a common characteristic of these salamanders, only about half of the species in this genus contain webbed feet.

<i>Desmognathus fuscus</i> Species of amphibian

Desmognathus fuscus is a species of amphibian in the family Plethodontidae. The species is commonly called the dusky salamander or northern dusky salamander to distinguish it from populations in the southern United States which form several distinct species, the southern dusky salamanders. The northern dusky salamander is the most widespread representative of its genus in Canada. It can be found in eastern North America from extreme eastern Canada in New Brunswick south to South Carolina. The size of the species' total population is unknown, but is assumed to easily exceed 100,000. The species' habitat differs somewhat geographically; dusky salamanders in the northern part of the range prefer rocky woodland streams, seepages, and springs, while those in the south favor floodplains, sloughs, and muddy places along upland streams. They are most common where water is running or trickling. They hide under various objects, such as leaves or rocks, either in or near water. Alternatively, they may enter burrows for protection. The dusky salamander lays its eggs close to water under moss or rocks, in logs, or in stream-bank cavities. The larval stage which follows is normally aquatic.

<span class="mw-page-title-main">Chamberlain's dwarf salamander</span> Species of amphibian

Chamberlain's dwarf salamander is a species of salamander in the family Plethodontidae, endemic to the United States. It is only found in the states of North Carolina and South Carolina. It was previously thought to be a color morph of the southeastern dwarf salamander, but was described in 2003 as a distinct species based on distinct morphology and behavior. A 2017 study reaffirmed it as being a distinct species. It is estimated that E. chamberlaini diverged from E. quadridigitata anywhere from 27 to 15 million years ago.

<span class="mw-page-title-main">Red salamander</span> Species of amphibian

The red salamander is a species of salamander in the family (Plethodontidae) endemic to the eastern United States. Its skin is orange/red with random black spots. Its habitats are temperate forests, small creeks, ponds, forests, temperate shrubland, rivers, intermittent rivers, freshwater, trees springs. Overall this species is common and widespread, but locally it has declined because of habitat loss and it is considered threatened in Indiana and New York. Red salamanders eat insects, earthworms, spiders, small crustaceans, snails, and smaller salamanders. To eat, they extend their tongue to capture prey on the tip of it and retract it back into their mouths. The red salamander, as a member of the family Plethodontidae lacks lungs and respires through its skin.

<span class="mw-page-title-main">Coastal giant salamander</span> Species of amphibian

The coastal giant salamander is a species of salamander in the family Dicamptodontidae. It is endemic to the Pacific Northwest of North America. There are three closely related species to this taxon: D. ensatus, D. copei, and D. aterrimus.

<span class="mw-page-title-main">Reticulated siren</span> Species of amphibian

The reticulated siren, also known as the leopard siren or colloquially as the leopard eel, is a species of aquatic salamander in the family Sirenidae. The species, which is endemic to the southeastern United States, was first formally described in 2018. This cryptic salamander is known only from three localities in southern Alabama and the Florida panhandle and is one of the largest animals in the United States to be newly described in the past 100 years.

References

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  5. 1 2 Heisler, N.; Forcht, G.; Ultsch, G.R.; Anderson, J.F. (1982). "Acid-base regulation in response to environmental hypercapnia in two aquatic salamanders, Siren lacertina and Amphiuma means". Respiration Physiology. 49 (2): 141–58. doi:10.1016/0034-5687(82)90070-6. PMID   6815749.
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  13. Crovo, J. A., Zeyl, J. N., & Johnston, C. E. (2016). Hearing and sound production in the aquatic salamander, Amphiuma means. Herpetologica, 72(3), 167-173.
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  16. Mitchell, Joseph. "Body Size and Diet of Amphiuma Means (Caudata: Amphiumidae) From Southeastern Virginia". meridian.allenpress.com. Retrieved 2024-02-21.