Paleontologists have unearthed a dense assemblage of dugong remains at the site of Al Maszhabiya in the Early Miocene Dam Formation of Qatar. This fossil site shows that the Arabian Gulf has repeatedly evolved sea cow communities with different species over the past 20 million years. One of these species, named Salwasiren qatarensis, is new to science.
An artistic reconstruction of a herd of Salwasiren qatarensis foraging on the seafloor. Image credit: Alex Boersma.
With a burly build and a downturned snout lined with sensitive bristles, dugongs (Dugong dugon) today resemble their relatives, manatees.
The one key difference between these aquatic herbivores, which are often called sea cows, is their tails: a manatee’s tail is rounded like a paddle while a dugong’s fluked tail is more similar to that of a dolphin.
Dugongs inhabit coastal waters from western Africa through the Indo-Pacific and into northern Australia.
The Arabian Gulf is home to the largest individual herd of dugongs in the world, where the sea cows serve as important ecosystem engineers.
As they munch on seagrass, dugongs reshape the seafloor by creating feeding trails that release buried nutrients into the surrounding water for other aquatic animals and plants to use.
“We discovered a distant relative of dugongs in rocks less than 16 km (10 miles) away from a bay with seagrass meadows that make up their prime habitat today,” said Dr. Nicholas Pyenson, the curator of fossil marine mammals at the National Museum of Natural History.
“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.”
Few places preserve as many of these bones as Al Maszhabiya, a fossil site in southwestern Qatar.
The bonebed was initially discovered when geologists conducted mining and petroleum surveys in the 1970s and noted abundant ‘reptile’ bones scattered across the desert.
In the early 2000s, paleontologists returned to the area and quickly realized that the fossils were not from ancient reptiles but sea cows.
Based on the surrounding rocks, Dr. Pyenson and his colleagues dated the bonebed to the Early Miocene epoch around 21 million years ago.
They uncovered fossils that revealed that this area was once a shallow marine environment inhabited by sharks, barracuda-like fish, prehistoric dolphins and sea turtles.
They identified more than 170 different locations containing sea cow fossils throughout the Al Maszhabiya site.
This makes the bonebed the richest assemblage of fossilized sea cow bones in the world.
The fossilized bones at Al Maszhabiya resembled the skeletons of living dugongs. However, the ancient sea cows still possessed hind limb bones, which modern dugongs and manatees have lost through their evolution.
The site’s prehistoric sea cows also had a straighter snout and smaller tusks than their living relatives.
The researchers described Al Maszhabiya’s fossil sea cows as a new species, Salwasiren qatarensis.
“It seemed only fitting to use the country’s name for the species as it clearly points to where the fossils were discovered,” said Dr. Ferhan Sakal, a researcher at Qatar Museums.
At an estimated 113 kg (250 pounds), Salwasiren qatarensis would have weighed as much as an adult panda or a heavyweight boxer.
But it was still among the smaller sea cow species ever discovered. Some modern dugongs are nearly eight times heavier than Salwasiren qatarensis.
Based on the fossils, the researchers posit that this region contained plentiful seagrass beds more than 20 million years ago, during a time in Earth’s history when the Gulf was a hotspot for biodiversity. Tending to these aquatic pastures were sea cows.
“The density of the Al Maszhabiya bonebed gives us a big clue that Salwasiren qatarensis played the role of a seagrass ecosystem engineer in the Early Miocene the way that dugongs do today,” Dr. Pyenson said.
“There’s been a full replacement of the evolutionary actors but not their ecological roles.”
The team’s discovery is reported in a paper published online in the journal PeerJ.
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N.D. Pyenson et al. 2025. High abundance of Early Miocene sea cows from Qatar shows repeated evolution of seagrass ecosystem engineers in Eastern Tethys. PeerJ 13: e20030; doi: 10.7717/peerj.20030
