[MUSIC PLAYING]
LUKE GROSKIN: This is the tail of a snail who
disappeared 75 years ago, a so-called Lazarus species.
PAUL JOHNSON: That's geek talk for you find something
that everybody thought was extinct
and so you're resurrecting something and bringing it back
from the dead.
LUKE GROSKIN: Finding an extinct species is extremely rare.
PAUL JOHNSON: They're usually in a really tightly located area,
just a mile or two of habitat that remains.
LUKE GROSKIN: As precious as they are obscure,
each has a fascinating story.
And for the oblong rocksnail, it's
one of sweeping revival at the bottom of a river.
In the spring of 2011, Nathan Whelan
was a biology graduate student serving invertebrates
on the Cahaba River.
NATHAN WHELAN: It's a beautiful river to kayak.
Good flow.
It's absolutely gorgeous.
That's one of the only rivers in Alabama
that hasn't been dammed and impounded.
LUKE GROSKIN: It was on a remote bend like this one
that Nathan picked up a rock and hit the jackpot.
NATHAN WHELAN: Well, I picked up the first one.
I took a look at it and I was looking at my hand.
I was like, that looks pretty suspicious.
I might want to hold on to this one for a second
and started picking up a couple other snails
and once I had two or three that looked like what I was looking
for, I started screaming, hey guys,
you got to come down here and take a look at this,
and I'm pretty sure they thought I was crazy.
LUKE GROSKIN: Nathan believed he'd
found the oblong rocksnail, a species that
hadn't been seen since 1933.
NATHAN WHELAN: So we collected about 35 of them
and brought them back to the Alabama Aquatic Biodiversity
Center.
LUKE GROSKIN: And showed them to Dr.
Paul Johnson, the facility's director.
PAUL JOHNSON: I was a bit skeptical to say the least.
I said, are you sure that you're not
confused with another close-related species?
He says, no.
I've got him.
LUKE GROSKIN: But proving it wasn't simple.
Whelan needed to go back to historic records
and then compare his specimens to museum specimens.
NATHAN WHELAN: And trying to determine, first,
did the shell even match?
LUKE GROSKIN: It did.
NATHAN WHELAN: But then also, we started
looking at the internal anatomy, especially that
of the radula, the snail teeth.
LUKE GROSKIN: Yes, snails have teeth.
Well, sort of.
Inside their mouths is a raspy strip called the radula which
they use to scrape surfaces for food and in many species,
the rattle is distinctly shaped.
Luckily for Whelan, the dental records matched.
PAUL JOHNSON: And sure enough, when I saw what he had,
he certainly had identified it correctly.
LUKE GROSKIN: After a couple of molecular tests
just to be sure, the oblong rocksnail was officially back.
But this wasn't the end of its story.
Five years later.
PAUL JOHNSON: I have several tanks
full of those animals that will be used for reintroduction
efforts in other areas of the Cahaba River
where the species used to occur.
LUKE GROSKIN: Nor is the oblong rocksnail alone in its journey.
Inside the tanks, tubs, and ponds at the Alabama Aquatic
Biodiversity Center are a myriad of mollusks and fish
all looking to make a comeback.
PAUL JOHNSON: Currently we have Alabama Creek Mussel, Alabama
Rainbows, Southern Combshells, Coosa Moccasinshell,
Pale Lilliput, Alabama Pearl Shells, Orangenacre Muckets.
I know I'm forgetting one or two species.
LUKE GROSKIN: And these are just a small portion
of the biodiversity found at the bottom of Alabama's 10
distinct river basins.
PAUL JOHNSON: We have the highest biodiversity
of freshwater mussels, gastropods,
and freshwater crayfish not only in the nation, but globally.
So the Coosa River, the Cahaba River, the Tennessee River,
each of those rivers will have a unique species within them that
don't occur in other basins.
LUKE GROSKIN: And just like the oblong rocksnail,
this makes them incredibly vulnerable.
PAUL JOHNSON: There's a tanker truck spill or some type
of accident and you can literally
lose a species that is limited just to one or two miles
and so the idea is that you can actually pick these things up.
We propagate them.
We put them someplace else so that one single event would not
eliminate the species.
LUKE GROSKIN: Now this may seem like a lot of fuss
over a bunch of bottom dwellers, but with their recovery
and federal listing as endangered
species comes a much broader revival.
PAUL JOHNSON: This project is a very convoluted clean water
project.
We have 76 federally listed mollusks,
mussels and snails combined.
LUKE GROSKIN: Whose unique tributary or stretch of river
gets monitored and protected.
With those protections comes cleaner water.
PAUL JOHNSON: And the Cahaba River, for example, they all
expanded the ruins-- if they were federally listed-- because
of improvements from sewage waste water treatment
upgrades in Birmingham.
LUKE GROSKIN: And of course, the added benefits
of the animals themselves.
PAUL JOHNSON: These animals literally
are the river's vacuum cleaners.
NATHAN WHELAN: They are important grazers
so they keep algae levels down.
They serve as a food source to other animals.
So if you like coming out here and seeing
a beautiful, beautiful place like this,
then you've got to have healthy invertebrates.
LUKE GROSKIN: It's a long, long road ahead for the oblong
rocksnail, but Dr. Johnson and Nathan Whelan think
they'll get there eventually.
For Science Friday, I'm Luke Groskin.