It’s eel-shaped and leopard-spotted, and it has no hind-limbs. It grows to two feet long. And yet until recently, hardly anyone had ever seen it.
A team of researchers has discovered of new species of salamander in the pine forests of northern Florida and southern Alabama. The so-called reticulated siren is the largest vertebrate found in the United States in decades, and the first new member of its family since 1944.
“It’s a really cool animal,” said David Steen, a conservation biologist at the Georgia Sea Turtle Center and an author of a genetic analysis of the salamander published in PLOS One. The salamander’s distinctive patterning “jumps out immediately,” he said.
Known for their size and bushy gills, sirens are a fixture in Southeastern swamps and watery ditches. Previously, Dr. Steen said, the genus was assumed to contain only two species: the lesser siren and greater siren, which can grow to three feet in length, one of the longest American salamanders.
But rumors of a third species have long persisted among reptile experts in Alabama and Florida. Informally called the leopard eel, one specimen ended up at Auburn University in 1970, misidentified as a greater siren.
In 1975, Robert Mount’s “Reptiles and Amphibians of Alabama” described an odd salamander that did not resemble the greater siren. Then on a rainy night in 1994, John Jensen, a biologist at the Georgia Department of Natural Resources, came across a flooded road in Florala, Ala., in which hundreds of leopard eels were squirming.
“The whole thing was kind of a campfire story,” said Sean Graham, a biologist at Sul Ross State University in Texas who helped lead the new study. “I was hearing rumors about it from people like Jensen, and then years would go by and I would never see a description of the species.”
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The process of formally describing a new species scientifically involves publishing a careful description of its anatomy and genetics; official recognition is often crucial to encouraging further research and determining conservation protections.
When Dr. Graham and Dr. Steen met at Auburn University in 2008, they decided to take a stab at describing the mystery species. While they found a few specimens to examine in regional museums, they needed fresh tissues for a DNA analysis, which can help reveal species differences invisible to the naked eye.
That meant catching wild leopard eels, which proved more difficult than expected. Despite several camping trips and multiple attempts to trap the elusive salamanders, they never had any luck.
Then in 2009, Dr. Steen — who was researching mud turtles in a beaver pond at Eglin Air Force Base on the Florida Panhandle — went down to check his turtle traps and found one of the long-sought sirens squirming inside.
He left Dr. Graham a simple voice mail: “I got one. You know what I mean.” Dr. Graham raced from Texas to Florida to see for himself.
“That was the first time I got to see one,” he said. “It was so different looking. So boldly patterned, colored, even its head shape. It has this kind of puny little head that’s very different from other sirens.”
“I was just letting it crawl through my fingers and freaking out. Hollering. It was great.”
Dr. Steen and Dr. Graham went to work. Without grants or dedicated funding, Dr. Steen said, they studied the specimen in their spare time. They enlisted the help of other experts, including Crystal Kelehear of Sul Ross State University (who is Dr. Graham’s wife) and Richard Kline of the University of Texas Rio Grande Valley.
In 2014, they caught three more of the salamanders in Lake Jackson, on the Florida-Alabama border. As it turned out, the siren’s genome is huge and packed into four sets of chromosomes, so the analysis took much longer than expected.
The new study relies on seven specimens — four recently collected, three from museum collections — to formally describe the siren. But while the reticulated siren is genetically distinct from the other two recognized species, its exact place on the family tree is uncertain.
That’s not a lot of specimens to work with, said David Wake, an evolutionary biologist at the University of California, Berkeley, who specializes in salamanders. “But despite documentation issues, I am convinced that they have identified a previously unnamed species,” he added.
Sirens are poorly understood. They like the thick muck at the bottom of swamps and ponds, which makes them hard to study. Their diet seems to consist of crustaceans and small insects, although they will occasionally eat plants, the only salamanders known to do so.
Researchers didn’t even know how they reproduced until 2013: Unlike other salamanders, the males fertilize eggs externally, as fish do.
Without knowing more about the reticulated siren’s population and range, Dr. Steen said, it’s difficult to assess its conservation status. So far, the species has been found only in pine forests of southern Alabama and in the Florida Panhandle, an ecosystem of creeks and bottomland swamps that is a hot spot of biological diversity.
“We’re hoping that one of the outcomes of this study getting out there is that it gets on people’s radar screens — funding agencies, state agencies — and they will begin to prioritize the work that is needed to fully understand the biology and conservation of this animal,” Dr. Steen said.
The genetic analysis also suggests that there may be other species of sirens as yet undiscovered. “A lot of the animals we thought were greater sirens and lesser sirens are probably the reticulated siren or other animals that we haven’t formally recognized,” Dr. Steen said.
Mr. Jensen, the biologist who once came across a migrating swarm of the animals, is excited to finally see the leopard eel get a proper name and formal recognition. “It’s about time the rest of the world gets to see and learn about what only a handful of biologists have known about for 30 years or so,” he said.
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