Southern dwarf siren

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Southern dwarf siren
P axanthus USGS.jpg
Status TNC G4.svg
Apparently Secure  (NatureServe) [2]
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Urodela
Family: Sirenidae
Genus: Pseudobranchus
Species:
P. axanthus
Binomial name
Pseudobranchus axanthus
Netting & Goin, 1942 [3]

The southern dwarf siren, (Pseudobranchus axanthus) is a perennibranch salamander lacking hind legs. Found exclusively in Florida, [2] 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.

Contents

Physical description

Southern dwarf sirens are thin, slimy salamanders that are frequently mistaken for eels. They have long bodies with bushy gills and small, three-toed fore legs. Coloration is generally brown, black, or gray, with yellow or tan stripes on their backs and sides. Adults reach a length of 10 centimetres (3.9 in) to 25 centimetres (9.8 in).

Southern dwarf sirens can easily be distinguished from amphiumas by size and the presence of hind legs, and from Siren spp. salamanders by the presence of three toes on each foot. Distinguishing between P. axanthus and P. striatus is more difficult, requiring comparison of patterns with a field guide, known distribution, or a karyotype test. P. axanthus has 32 chromosomes, while P. striatus has 24. A costal groove count may assist in differentiating P. a. axanthus and P. a. belli, as the former has 34–37 costal grooves, while the latter has 29–33 (Petranka, 1998).

Distribution

P. axanthus is found throughout eastern Florida, with P. a. axanthus located in the northern two-thirds of the range and P. a. belli located in the southern third. P. axanthus prefers cypress ponds, ditches, swamps and marshes, and other aquatic and semiaquatic habitats. [4] P. axanthus is frequently associated with water hyacinth.

Reproduction

Little is known about the reproduction of wild sirenid salamanders. Eggs of P. axanthus have been found from November through March, and are usually attached singly to aquatic plants. Eggs average 3 mm in diameter and have three jelly envelopes. [4]

In captivity, eggs were attached singly at night to floating vegetation in groups of two to five a day. Larvae hatch out at about 5 mm after around three weeks.

Diet

Southern dwarf sirens eat a variety of food items, including small worms, chironomids, amphipods, and ostracods. [4] Dwarf sirens have surprisingly small mouths, but will likely eat any invertebrate they can swallow. In captivity, adult Daphnia magna , whiteworms, blackworms, and tubifex worms are readily taken.

Ecology

During dry spells, P. axanthus is known to aestivate in muddy burrows, and adults have been kept for periods longer than two months in dry soil with no ill effects in the laboratory. [4]

Related Research Articles

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Amphibians are four-limbed and ectothermic vertebrates of the class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terrestrial, fossorial, arboreal or freshwater aquatic ecosystems. Thus amphibians typically start out as larvae living in water, but some species have developed behavioural adaptations to bypass this.

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

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

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

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

The greater siren 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 the southeastern United States.

<span class="mw-page-title-main">Two-toed amphiuma</span> Species of amphibian

The two-toed amphiuma 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".

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

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

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

The marbled salamander is a species of mole salamander found in the eastern 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">Southeastern dwarf salamander</span> Species of amphibian

The southeasterndwarf salamander, formerly known as the dwarf salamander, is a species of salamander native to the southern United States, ranging primarily from southern North Carolina south to northern Florida, with some populations from southwestern Alabama to eastern Louisiana. Some sources refer to it as the four-fingered manculus, dwarf four-toed salamander, or the Florida dwarf salamander.

<span class="mw-page-title-main">Dwarf siren</span> Genus of amphibians

Dwarf sirens are eel-like salamanders of the genus Pseudobranchus. Dwarf sirens possess external gills throughout adulthood and lack hind legs. Dwarf sirens can be distinguished from members of the genus Siren in that dwarf sirens have three toes on each foot rather than four. Like sirens, dwarf sirens are restricted to the Southeastern United States.

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

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References

  1. SSC Amphibian Specialist Group (2022). "Pseudobranchus axanthus". IUCN Red List of Threatened Species . 2022: e.T59489A196342247. doi: 10.2305/IUCN.UK.2022-1.RLTS.T59489A196342247.en . Retrieved 1 November 2022.
  2. 1 2 "Pseudobranchus axanthus". NatureServe Explorer. Retrieved 1 November 2022.
  3. Amphibian Species of the World 5.5. research.amnh.org/vz/herpetology/amphibia.
  4. 1 2 3 4 Petranka, 1998