TARPON SPRINGS — It didn't take a beachgoer foot-shuffle for Shawn Campbell to detect the stingray that turned his St. Patrick's Day into an Internet sensation.
There it was, right before Campbell's eyes, wings estimated at 7 feet wide undulating on the sea floor near a sunken barge popular with divers about 8 miles west of Tarpon Springs.
"Everyone was focused on the wreck so I started to ditter out into the sand and it was just laying there, the biggest creature I've ever seen out in the water," said Campbell, 38, a dive master with Narcosis Scuba Center in Tarpon Springs.
Campbell counts himself lucky that the massive sea creature stuck around long enough for him to alert the others in the tour he was leading.
"I was too excited to be nervous about getting close to it, and it just let us hang out before it swam off completely by itself."
Diver Howard Cohn trained his GoPro camera on the stingray as Campbell swam beside it for comparison, knowing it would take video evidence to convince people he wasn't telling a tall tale.
He was right. "As soon as I put the video online for my dive group," Cohn said, "the messages came pouring in, like, 'Seriously? Look at the size of that thing!"
The dive group calls its brush with such a massive stingray a once-in-a-lifetime experience. But there are more of the creatures out there, even bigger than the one they now call "Shawn's Dinosaur," according to an expert at Mote Marine Laboratory and Aquarium in Sarasota.
This one is likely a roughtail stingray, the largest of the species, said Dr. Robert Hueter, Mote Marine's senior scientist and director of the Center for Shark Research.
Roughtail stingrays, named for the row of thorny protuberances down the spine and distinctive tail, are indigenous to the warm, coastal Gulf waters off Tarpon Springs and can grow to more than 8 1/2 feet wide and 800 pounds.
Hueter reviewed the video from the Narcosis Scuba Center and estimated the length of the stingray's diamond-shaped body, or disc, at 7 feet across — about average for the species.
But one thing is unusual about the encounter off Tarpon Springs, Hueter said.
Large, roughtail stingrays are among the deepest diving of the species, recorded at depths up to 899 feet. The Tarpon Springs divers were at just 35 feet to 40 feet below the surface, in what the video shows to be bright sunlight.
For this reason, beachgoers doing the stingray shuffle with their feet to protect against a sting from the venomous tail barbs also are unlikely ever to encounter a large roughtail.
When the docile stingray decided it was time to take off, diver Cohn got a clear view of a large remora or sucker fish attached to the bottom of its tail. Remoras are usually seen alongside sharks, Cohn said, and this one was at least 3 feet long.
"Stingrays are common in these waters," he said, "but I never would have thought I'd see one so big it had a remora on its tail."
For Campbell, the St. Patrick's Day tour gives him heart because it signals that there still are plenty of fish to be found in the local waters of the Gulf of Mexico.
"We saw a massive goliath grouper, starfish, hermit crabs," he said. "Forget the oil spill, or red tide. The wildlife off our coast is amazing right now and I don't think a lot of people realize just how much the entire ecosystem is just thriving."
Contact Anastasia Dawson at firstname.lastname@example.org or (813) 226-3377. Follow @adawsonwrites.