The fossilised skull of an ancient, extinct dolphin has been discovered in a river that runs through Charleston, South Carolina.
And the new species, a dwarf dolphin that lived 28-30 million years ago, looks very weird.
The dolphin’s scientific name, Inermorostrum xenops, means “defenceless snout” – which refers rather cruelly to the fact that this dolphin had no teeth.
As well as being toothless the dolphin would only grow to around four feet, smaller than its closest relatives, and smaller than modern bottlenose dolphins which are usually between seven and 12 feet in length.
The discovery has implications for what’s currently believed about the evolution of whales and dolphins.
“The discovery of a suction-feeding whale this early in their evolution is forcing us to revise what we know about how quickly new forms appeared, and what may have been driving early whale evolution,” Canadian Museum of Nature palaeontologist Danielle Fraser said.
“Increased ocean productivity may have been one important factor.”
Robert Boessenecker, lead author of the study that was published in the journal Proceedings of the Royal Society B, said that Inermorostrum xenops is the earliest known species of suction feeder – a species that vacuums up their prey.
The animal would have had a diet similar to that of a walrus, the researchers said, sucking up fish, squid and other soft-bodied invertebrates from around the sea floor. It’s believed that the extinct dolphin may even have had whiskers.
Boessenecker said this discovery shows it only took four million years to evolve a toothless, suction-feeding specialist from primitive tooth whales.
“We also found that short snouts and long snouts have both evolved numerous times on different parts of the evolutionary tree – and that modern dolphins like the bottlenose dolphin, which have a snout twice as long as it is wide, represent the optimum length as it permits both fish catching and suction feeding,” he said.