'Rat' could be whale ancestor
It sounds like a stretch, but a new study suggests that the missing evolutionary link between whales and land animals is an odd raccoon-sized animal that looks like a long-tailed deer without antlers. Or an overgrown long-legged rat.
The creature is called Indohyus, and recently dug up fossils reveal some crucial evolutionary similarities between it and water-dwelling cetaceans, such as whales, dolphins and porpoises.
For years, the hippo has been the leading candidate for the closest land relative because of its similar DNA and whale-like features.
So some scientists were sceptical of the new hypothesis by a US anatomy professor whose work was published yesterday in the journal Nature.
Still, some researchers have been troubled that hippos seem to have lived in the wrong part of the world and popped up too recently to be a whale ancestor.
Newer fossils point to the deer-like Indohyus. The animal was a 'missing link' to the sister species to ancient whales, said Hans Thewissen, an anatomy professor at Northeastern Ohio Universities College of Medicine.
'As a zoo animal, it looks nothing like a whale,' Professor Thewissen said. But when it came to anatomical features, the Indohyus 'is quite strikingly like one'.
Professor Thewissen, who earlier published papers on fossils of what he called the first amphibious whale and the skeleton of the oldest known whale, studied hundreds of Indohyus bones unearthed from mudstone in Indian-administered Kashmir.
From that cache of bones he created a composite skeleton of a 48 million-year-old creature.