Short-lived Marine Mammal Sucked Up Food Like a Vacuum Cleaner
Posted on October 6, 2015
Researchers have identified a new species of hippo-sized marine mammal that lived about 23 million years ago. The species belongs to a group known as Desmostylia. The Desmostylians lived in an interval between 33 million and 10 million years ago.
The new species has been named Ounalashkastylus tomidai. The fossils of four individuals were found on Unalaska, an Aleutian island in the North Pacific. The individuals include a baby which indicates there was a breeding population of desmos along the Alaska coast millions of years ago.
Researchers believe the Desmostylians swam like polar bears and were large enough to avoid being a major predator target. They were vegetarians and had a completely unique style of eating. To eat they would clench their teeth and buttress their lower jaw with their teeth against the upper jaw. They then used their powerful mouth muscles - combined with the shape of the roof of their mouth - to suction-feed vegetation from coastal bottoms like a vacuum. Their diet would have included near-shore marine plants, like marine algae and sea grass.
Louis L. Jacobs, a professor of earth sciences at Southern Methodist University and leader of the study, says in a statement, "The new animal -- when compared to one of a different species from Japan -- made us realize that desmos do not chew like any other animal. They clench their teeth, root up plants and suck them in. No other mammal eats like that. The enamel rings on the teeth show wear and polish, but they don't reveal consistent patterns related to habitual chewing motions."
The new species is also a new desmos genus. Jacobs says desmostylians in the same family diverged from one another in key physical characteristics, particular in their tooth and jaw structure.
Dr. Louis Jacobs discusses Ounalashkastylus tomidai in the following video from SMU. Take a look:
A research paper on the new species can be found here in the journal, Historical Biology.
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