Tiny sea cow species thrived in Arabian Gulf 21 million years ago

A shallow sea that once covered southwestern Qatar held something remarkable: not one ancient sea cow, but dozens upon dozens of them, scattered across what paleontologists now call the world's richest fossil sea cow graveyard.

In December, researchers from the Smithsonian's National Museum of Natural History and Qatar Museums formally named this newly discovered species Salwasiren qatarensis—a creature that weighed around 250 pounds, about the size of an adult panda, and roamed seagrass meadows during the Early Miocene, roughly 21 million years ago. The findings, published in PeerJ, emerge from excavations at Al Maszhabiya, a fossil site in southwestern Qatar where sea cow remains turn up at more than 170 separate locations.

"We discovered a distant relative of dugongs in rocks less than 10 miles away from a bay with seagrass meadows that make up their prime habitat today," said Nicholas Pyenson, curator of fossil marine mammals at the Smithsonian. "This part of the world has been prime sea cow habitat for the past 21 million years—it's just that the sea cow role has been occupied by different species over time."

What makes Salwasiren distinct from its modern cousins—the dugongs that still graze in the Arabian Gulf today—is both subtle and telling. The ancient animals retained hind limb bones that living dugongs and manatees lost over millions of years of evolution. They had straighter snouts and smaller tusks. Yet they filled the same ecological role: maintaining underwater seagrass meadows through constant grazing and sediment disturbance, much as dugongs do now.

A 21-Million-Year Connection

The Al Maszhabiya site itself has a modern history worth noting. Geologists first stumbled on it in the 1970s during mining and petroleum surveys, dismissing the bones as reptile remains. When paleontologists returned in the early 2000s, they recognized the treasure beneath their feet. "The area was called 'dugong cemetery' among the members of our authority," said Ferhan Sakal, head of excavation and site management at Qatar Museums. "But at the time, we had no idea just how rich and vast the bonebed actually was."

After obtaining permits in 2023, Pyenson and Sakal's team began systematic work. The surrounding rock layers told a story of a thriving ecosystem: sharks, barracuda-like fish, prehistoric dolphins, and sea turtles all shared these waters with the sea cows.

Today's dugongs face pressures their ancestors never encountered. Accidental fishing net entanglement, coastal development, rising water temperatures, and increasing salinity threaten both the animals and the seagrass meadows they depend on. But the fossil record offers something valuable: evidence of how these ecosystems responded to past climate stress and salinity shifts. "If we can learn from past records how the seagrass communities survived climate stress or other major disturbances like sea-level changes and salinity shifts, we might set goals for a better future of the Arabian Gulf," Sakal noted.

The team has made their findings accessible through 3D digital scans available on the Smithsonian's open-source Voyager platform—interactive models of the fossil skull, vertebrae, teeth, and skeletal parts that researchers and curious minds can explore from anywhere. They're also pursuing UNESCO World Heritage site status for Al Maszhabiya itself, recognizing that protecting these fossil beds matters not just for science, but for Qatar's cultural and natural heritage.

As Pyenson observed, there's been "a full replacement of the evolutionary actors but not their ecological roles." The sea cows have changed. The Gulf remains.