© T. LambThe yellow patch on the nose is a distinctive feature
The salamander is so distinct that it's been classified within its own genus, a taxonomic grouping that usually includes a host of related species.
The creature breathes through its skin, and unusually for its kind, males and females have different colouration.
Such a distinct amphibian has not been found in the US for half a century.
The researchers who discovered the salamander describe it in the Journal of Zoology. They have dubbed it the 'patch-nosed' salamander after the yellow patch on the animal's snout.
The tiny animal averages just 25 to 26mm long.
They found so few of the animals that either it is highly secretive, or more likely it survives in such small, isolated numbers that it is already at risk of extinction.
"This animal is really a spectacular find," says biologist Carlos Camp of Piedmont College in Demorest, Georgia, who led the team which described the new species.
"It is the first genus of amphibian, indeed of any four-footed vertebrate, discovered in the US in nearly 50 years."
Around the world, there are approximately 500 species of salamander.
Two-thirds of these species are lungless, breathing entirely through their porous, moist skin.
The Appalachian Highlands of the southeastern US is a hot spot for lungless salamander diversity, with species occupying a variety of moist or wet environments including living in streams, underground, among the leaf litter of the forest floor, up cliffs and in trees.
"The salamander fauna of the US, particularly of the southern Appalachians, has been intensively studied for well over a century, so the discovery of such a distinct form was completely unsuspected," says Carlos.
Striking differences
Two graduate students, Bill Peterman of the University of Missouri, Columbia and Joe Milanovich of the University of Georgia, Athens discovered the first example of the species, scientifically named Urspelerpes brucei. They took the animal to Camp for identification.
"When we realised that it was something novel, we contacted a geneticist, Trip Lamb, of East Carolina University, Greenville and a bone specialist, David Wake of the University of California at Berkeley. John Maerz, a professor at the University of Georgia, completed the research team," says Carlos.
The team's investigations revealed just how novel the salamander is.
© T. LambA yellow male with stripes above a more muted female
But the amphibian also looks strikingly different to other species.
For a start, it has the smallest body size of any salamander in the US. It is also the only lungless salamander in the US whose males have a different colour and pattern than females, a trait more characteristic of birds.
Males have a pair of distinct dark stripes running down the sides of the body and a yellow back. Females lack stripes and are more muted in colour.
Males also have 15 vertebrae, one less than females. Yet while most species of lungless salamander have male and females of differing sizes, those of Urspelerpes brucei are close to being equal in size.
Uniquely for such a small lungless salamander, Urspelerpes brucei has five toes, whereas most other small species have reduced that number to four.
The behaviour and lifestyle of the salamander remain a mystery.
The animal's jaw and teeth structure suggest that it eats small, terrestrial prey such as insects caught using a projectile tongue as some other species of lungless salamander do.
So far, Camp's team have recovered just eight adults, all from within or alongside a single stream. Four were collected hiding under rocks and four in loose leaf litter. Three were females, each carrying eggs.
The last new genus of amphibian living in the US to be described, in 1961, was also a lungless salamander, the Red Hills Salamander of southern Alabama.
I Found striking salamander in Dayton Ohio Creek. They are really Cool.