redOrbit Staff & Wire Reports – Your Universe Online
Researchers at the Senckenberg Research Institute in Dresden have discovered that a freshwater turtle species declared extinct has not died out as experts had previously believed — in truth, it never existed.
The Seychelles mud turtle Pelusios seychellensis was originally described in 1906 as a species endemic to Mahe island, but despite an exhaustive search by scientists, living members of the species had not been discovered since the 19th century. As a result, the International Union for the Conservation of Nature (IUCN) declared it extinct in 2003, according to AFP reports published last week.
Now, however, a team of German and Austrian researchers has examined DNA evidence and discovered that there never had been such a species. What was mistakenly believed to be the new species Pelusios seychellensis was a widespread West African turtle called Pelusios castaneus, which may have been brought to Mahe island many years ago and mistaken as a native to the archipelago.
Furthermore, dried museum specimens of the now-discredited species were incorrectly labeled as having originated from the Seychelles, they told the French news organization. Scientists had long been “puzzled” over the similarities between P. seychellensis and P. castaneus, but came to the conclusion that they must be two separate and distinct species due to the immense geographical distance separating them, the AFP added.
“It was assumed the species had been exterminated, [but] we have examined the DNA of the original specimen from the museum in Vienna and discovered that these turtles are not a separate species,” Professor Uwe Fritz, the director of the Museum of Zoology at the Senckenberg Natural History Collections in Dresden, explained in a statement.
“The species Pelusios seychellensis has therefore never existed,” he added. “In fact, for a long time researchers were amazed that the supposed Seychelles turtles looked so deceptively similar to the West African turtles. But due to the great geographic distance, it was thought this had to be a different species, which is why the assumed Seychelles turtles were also described as a new species in 1906.”
P. castaneus is native to the western coast of Africa from Senegal to Angola, according to reports. Due to the tremendous amount of land and ocean between that region and the Seychelles, it is unlikely that the approximately hand-sized turtle would have been able to make the journey through natural means.
While the researchers believe that it could have been transported from West Africa to the Seychelles by humans during the late 1800s, the study authors believe that it is more likely a museum labeling error is to blame.
“This would not be the first time that a museum labeling error gave the world a non-existing turtle species,” the report said, according to AFP. “A New Guinea species described in 1905 turned out to be a North American snapping turtle for which the data had been confounded. And a Vietnamese species described in 1941 was later found to have been an escaped pet tortoise from Madagascar.”
Their findings have been published in the journal PLoS One.