Professor unearths pygmy sea cow

What the heck is this? paleontologist wondered after digging up teeth and bits of skull

By Peggy Curran, Vancouver Sun – December 12, 2009

An ancient pygmy sea cow isn’t the kind of thing you find every day.

More like every 45 million years. So when Karen Samonds, a paleontologist whose work focuses on the evolutionary history of Madagascar’s modern fauna, discovered fossilized teeth and bits of skull in sandstone and limestone rocks in the island nation off the east coast of Africa, she wasn’t immediately sure what she had stumbled upon.

For one thing, the teeth were many times larger than the tiny bones and teeth of the land mammals she usually studies.

Samonds, a curator at McGill University’s Redpath Museum, said it was one part “Eureka!” moment—“I couldn’t believe we actually found a mammal”—and two parts “What the heck is this?”

Samonds’s sea cow is a prehistoric cousin of today’s dugongs and manatees, about three-quarters the size of the modern creatures.

The sea cow dates back to the Middle Eocene period, between 37.2 million and 48.6 million years ago.

“The fossils of this ancient sea cow are unique in that it has a full set of relatively unspecialized teeth, whereas modern sea cows have a reduced dentition specialized for eating sea grass,” said Samonds, whose discovery will be published Saturday in the Journal of Vertebrate Paleontology.

“It may also be the first fully aquatic sea cow. Confirmation will depend on recovering more of the skeleton, especially its limbs.”

An assistant professor in the departments of anatomy and cell biology, and dentistry, Samonds is intrigued by Madagascar’s remarkable animal population and how they got there.

“How, when and from where they arrived on the island has remained largely unknown due to a 65-million-year gap in the fossil record.”

Samonds works with scientists from the University of Antananarivo in Madagascar, often spending several weeks in remote rocky sites where fossils can all too easily be worn away by millions of years of wind and rain.

She found the first piece of the fossil skull in 2003, returning several times until she was able to reconstruct most of the skull and parts of the ribs. She plans to go back to the area again in the spring on an expedition funded by National Geographic.

Samonds’s sea cow is thought to have evolved from the land-based, grass-eating creatures that preceded it to take advantage of shallow coastal waters and estuaries. She is optimistic her team will uncover more fossils of marine, freshwater and land animals encased in the sediment of those long lost waterways and along the modern-day shoreline.