Dwarf sirens are

eel Eels are ray-finned fish belonging to the order Anguilliformes (), which consists of eight suborders, 20 families, 164 genera, and about 1000 species. Eels undergo considerable development from the early larval stage to the eventual adult stage ...

-like

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 ...

s of the genus ''Pseudobranchus''. Dwarf sirens possess external

gill A gill () is a respiration organ, respiratory organ that many aquatic ecosystem, 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 r ...

s throughout adulthood and lack

hind A hind is a female deer, especially a red deer. Places * Hind (Sasanian province) (262-484) * Al-Hind, a Persian and Arabic name for the Indian subcontinent * Islamic State – Hind Province, claimed province of the IS in India * Hind (cra ...

leg A leg is a weight-bearing and locomotive anatomical structure, usually having a columnar shape. During locomotion, legs function as "extensible struts". The combination of movements at all joints can be modeled as a single, linear element cap ...

s, and can be distinguished from members of the genus '' Siren'' in that dwarf sirens have three

toes Toes are the digits of the foot of a tetrapod. Animal species such as cats that walk on their toes are described as being ''digitigrade''. Humans, and other animals that walk on the soles of their feet, are described as being ''plantigrade''; ...

on each

foot The foot (: feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is an organ at the terminal part of the leg made up o ...

rather than four. Whereas sirens have three gill slits, dwarf sirens keep just a single slit.Dwarf siren - The University of Texas at Austin
/ref> Like sirens, dwarf sirens are restricted to the

Southeastern United States The Southeastern United States, also known as the American Southeast or simply the Southeast, is a geographical List of regions in the United States, region of the United States located in the eastern portion of the Southern United States and t ...

Species

The genus ''Pseudobranchus'' consists of the following extant species: * Southern dwarf siren (''P. axanthus'') **Narrow-striped dwarf siren (''P. a. axanthus'') **Everglades dwarf siren (''P. a. belli'') * Northern dwarf siren (''P. striatus'') **Broad-striped dwarf siren (''P. s. striatus'') **Gulf Hammock dwarf siren (''P. s. lustricolus'') **Slender dwarf siren (''P. s. spheniscus'') There are also two extinct species known from fossil evidence: * †''Pseudobranchus vetustus'' (

Miocene The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

) * †''Pseudobranchus robustus'' (

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

of Florida)

References

External links

Pseudobranchus - Encyclopedia of Life
Sirenidae Taxa named by John Edward Gray {{salamander-stub