Researchers may have found a new species of sea cow on Channel Islands

Chris Everett, a volunteer preparator, works on the ribs of the sea cow fossil.

Researchers this week came miles closer to finding answers about a long-extinct sea cow discovered on a remote island off the Ventura coast.

A skeleton discovered last year had been buried in a steep ravine on Santa Rosa Island, part of Channel Islands National Park.

This week, the skeleton was packed into a crate and airlifted to the island’s pier. From there, the piece of ancient history, just under 500 pounds, was loaded onto a boat for the three-hour trip to the mainland.

“This is one of the oldest sea cow fossils on the Pacific Coast” of North America, said Jonathan Hoffman, a paleontologist with the Santa Barbara Museum of Natural History.

Hoffman spent weeks with teams slowly, methodically excavating the bones.

“For this region, it would be one of, if not the oldest sea cow fossils,” he said. “So it’s filling in an important part of the sea cow story.”

The find marked a first for the five-island national park off Ventura and likely has uncovered a new species of sea cows, also called sirenians.

The fossil, which included a skull and partially-intact skeleton, is estimated to be 20 to 25 million years old.

This week, a 500-pound sea cow fossil was loaded into a crate and airlifted out of a ravine on a remote island off Ventura.

It’s the skull that will help experts determine whether it is a newly discovered species. 

Jorge Velez-Juarbe, a sea cow expert at the Natural History Museum of Los Angeles County, will study its features to see if it is new, and if so, where it fits into the sirenian family tree.

The top priority right now is to get the skull prepped out, Hoffman said.

That work could take months as they slowly break through layers of rock using dental picks and a small hand drill called an air scribe.

MORE:Team unveils Channel Islands mammoth skull

The rest of the skeleton includes a couple of dozen ribs, a dozen vertebrae and a humerus.

“It’s very rare to find a complete skeleton,” Hoffman said. In this case, the animal likely had been on the ocean floor for a while before it was buried.

But each piece can help fill in the story of the now long-extinct sea creatures.

Shells found in the same rock layer can help them get as close as possible to an age. Teeth can tell them more about how and where the sea cows lived, from the temperature of the water to what they ate.

At one time, experts say there were more than a dozen different species of sirenians living around the world. They typically lived in shallow water and ate seagrasses. 

The cause of their decline is unclear but may be linked to cooling temperatures and availability of seagrass. Today’s living sirenians are manatees and dugongs.

A sea cow skeleton was loaded inside this crate and brought to the Channel Islands National Park headquarters on Tuesday.

This one lived not only millions of years ago but also in a much different place.

When the sea cow wound up buried on the ocean floor, it would have been farther south, likely closer to where San Diego is today.

Over millions of years, the sea cow remains caught a ride on the tectonic plate with bits of rock that would later become the Channel Islands.

MORE:Researchers find skull, ribs of extinct sea cow in Channel Islands National Park

Probably in just the past few years, the bones were exposed as fierce wind and rain eroded the cliff.

In 2012, structural geologist Scott Minor was checking out faults that crisscross the island when he saw something unusual sticking out of a rocky ravine.

He looked closer and realized it was a ribcage.

A sea cow fossil recovered from Santa Rosa Island is now being studied at the Santa Barbara Museum of Natural History.

Minor took photographs, notes and recorded the GPS coordinates to pass on to experts. Five years later, a team of paleontologists got to work in the remote spot.

Last fall, Hoffman worked with small teams, carefully crouching on a slope of shifting rocks and dirt to dig around the skull, ribs and vertebrae. Then they covered the bones in plaster to help them weather the winter months.

In August, they went back to excavate.

They brought the skull to the mainland two weeks ago. Then on Tuesday, a crane lifted the crate carrying the rest of the skeleton onto the dock at the park’s Ventura headquarters.

From left, Lulis Cuevas, a park ranger for Santa Rosa Island, watches Ruben Underwood-Aguilar, Jonathan Hoffman (standing), Chris Everett and Tara Redinger as they chip away stone at a site where they found ribs of a sirenian, or sea cow, on Santa Rosa Island.

From there, Hoffman was driving it to the Santa Barbara museum.

“Figuring out that we’ve got invertebrate fossils known from older rocks is pretty exciting,” he said as a small group waited for the boat to arrive.

That boosted experts’ confidence in the age range of 20 million to 25 million years old.

“We’re missing a big part of the story of how they were distributed over time,” Hoffman said.

Those are some of the pieces that this fossil could help fill in.