CORVALLIS, Ore., Aug. 18 (UPI) -- Salamanders once inhabited the Caribbean. It's a fact scientists arrived at only recently, after discovering the first ever salamander fossilized in amber.
The specimen, found in what is now the Dominican Republic, appears to have been involved in a skirmish in which its leg was bitten off prior to falling into a large deposit of tree sap.
As of now, the fossil is the only example of the never-before-seen (and now extinct) species, Palaeoplethodon hispaniolae -- a name chosen by the authors of a new paper on the discovery, published online this week in the journal Palaeodiversity.
Researchers from Oregon State University and the University of California at Berkeley say the family to which the species belonged, Plethodontidae, is now common in North America and especially prevalent in Appalachia.
But what scientists don't know is how the salamander arrived on the island and why its relatives all disappeared.
"There are very few salamander fossils of any type, and no one has ever found a salamander preserved in amber," study author George Poinar, Jr., a professor emeritus in the Oregon State's College of Science, said in a press release. "And finding it in Dominican amber was especially unexpected, because today no salamanders, even living ones, have ever been found in that region."
"The discovery of this fossil shows there once were salamanders in the Caribbean, but it's still a mystery why they all went extinct," Poinar added. "They may have been killed by some climatic event, or were vulnerable to some type of predator."
The specimen is somewhere between 20 and 30 million years old. Researchers say it could have traveled to the islands on a piece of debris, or crossed a land bridge that appeared during a period of low sea levels.
It's also possible that the species' lineage dates back 40 to 60 million years, to a time when the Proto-Greater Antilles -- a chunk of land that included the present-day islands of Cuba, Jamaica, Puerto Rico and Hispaniola -- was still adjoined to North and South America.
Researchers say rare finds like these can help paleontologists piece together the geologic and biological evolution of ancient Earth.
"There have been fossils of rhinoceroses found in Jamaica, jaguars in the Dominican Republic, and the tree that produced the Dominican amber fossils is most closely related to one that's native to East Africa," Poinar said. "All of these findings help us reconstruct biological and geological aspects of ancient ecosystems."