It’s a strong statement to say a creature is only found in one place on Earth. That there’s something so unique about a particular location that it’s the only place where a creature can survive.
But, tucked into the rocks and crevices of neighboring streams, each draining off the Blue Ridge Mountains, scientists have discovered two new species of crayfish found only in western North Carolina and nowhere else on the planet.
Meet the Stony Fork crayfish, scientific name Cambarus lapidosus. It’s named after a small tributary of the Yadkin River, the only place this little critter is found.
Also meet the Falls crayfish, Cambarus burchfielae, named after the Lewis Fork drainage, the only place it’s found.
“This is really neat,” said Bronwyn Williams, research curator of non-molluscan invertebrates at the North Carolina Museum of Natural Sciences in Raleigh and coauthor of a study about the findings, published in the journal Zootaxa. “These crayfish are what we call narrow-range endemics, meaning they are highly restricted in their geographic range because they can only live in specific environmental conditions.”
In other words, their bodies have adjusted to be able to survive only in one specific place.
The two new crayfish species had been lumped in with a widespread crayfish species called Cambarus species C. Those crayfish species are found in mountain drainages all along the Atlantic slope, from Philadelphia to Columbia, South Carolina. Scientists believed they were all closely related because they look the same.
And if you look at the newly identified crayfish species, they look like most other crayfish.
But …
Williams and coauthors Michael Perkins and William Russ, from the North Carolina Wildlife Resources Commission, decided to take a closer look. They studied genetic data, the crayfish bodies and how the creatures adapted to where they lived. The scientists also compared newly collected field specimens with those found in the museum’s collection.
All that data indicated that the new crayfish species were like a group found in the south-central Appalachians of North Carolina, Cambarus robustus, the big water crayfish.
The researchers also found the new crayfish were just different enough to be classified as its own unique species, living in a specific corner of the planet and nowhere else.
Besides being cool, what does this discovery mean? It’s all about taxonomy, the branch of science concerned with classification.
“Taxonomy is essential for conservation,” said Williams. “If a unique creature does not have a formal name, it is not eligible for the resources needed to manage and protect it.”
Now that conservationists can show the streams are home to unique species of crayfish, more resources may be available to protect the area.
It also suggests that thousands of years ago, a phenomenon called stream capture, or stream piracy, happened in the area. That’s where a localized, temporary, aquatic connection bridged the area where the headwaters of the Stony Fork and Lewis Fork are now. The waterway eroded into a divide and diverted an adjacent waterway into itself. That set up a unique area, with currents, nutrients and hiding spots where these crayfish evolved.
How crayfish survive in sediment-filled water has been a mystery to scientists.
