Scientists say they've identified a specimen of a small, rare species of shark dubbed a "pocket shark," only the second example of the species ever found.
The small and young shark was fished up in 2010 along with other marine creatures by a research ship from the National Oceanic and Atmospheric Administration, and spent years in a giant freezer awaiting identification, researchers say.
The only other example was found more than three decades ago off Peru's Pacific coast, and now resides in a Russian museum.
The Gulf of Mexico specimen is a male, about 5.5-inches long, and was likely only a few weeks old when caught, says NOAA's Mark Grace, lead author of a study on the identification published in Zootaxa.
That was borne out by the presence of an umbilical scar, he says.
"Discovering him has us thinking about where mom and dad may be, and how they got to the Gulf," he says. "The only other known specimen was found very far away, off Peru, 36 years ago."
Grace found the specimen in the holdings of the NOAA Fisheries' Pascagoula, Miss., lab, and recruited researchers at Tulane University and fellow NOAA scientists to conduct an examination.
Although the species is small, the term "pocket" shark doesn't refer to its size, but rather to two pockets in its body next to its front fin, the purpose of which is unknown.
"I wasn't really sure what it was," Grace says of his discovery in the lab's freezer. "That pocket over on the pectoral fin, I had never seen anything like that on a shark."
The Peruvian specimen, the only other pocket shark ever found, was a female about 17 inches long.
Adult females may be larger than the males, the researchers speculate.
The NOAA and Tulane scientists have placed the specimen in the genus Mollisquama, and consider it a close relative of kitefin and cookie cutter sharks, all members of the shark family Dalatiidae.
"It's cute," says Tulane biologist Michael Doosey, who co-authored the identification study. "It almost looks like a little whale."
Even though only two specimens are now known to science, the fact that they were discovered in two separate regions of the world's ocean suggest the elusive species may in fact be widespread.
"There's others" out there, Grace says. "We just haven't caught them yet."