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"With these new discoveries the whale fossil record is now so complete," Hans Thewissen, of Northeastern Ohio Universities College of Medicine, said.
"It shows us so well how whales became aquatic that it is probably the best, or one of the best, examples of evolution where these major changes are documented with fossils," he
added in a telephone interview.
colleagues uncovered fossils of a fox-size mammal called Ichthyolestes, and Pakicetus which resembled a wolf.
The research is reported in the science journal Nature.
The ankle bones are seen only in a group of animals known as artiodactyls such as cows, pigs and hippos.
But the heads of the creatures have whale-like features.
"They are whales that were still living on land.
Their relatives are a group of even-toed ungulates," Thewissen
said, using another term for artiodactyls.
Craig George is working with Hans ...
Craig George is working with Hans Thewissen of Northeast Ohio Medical University to find out if there is a way to measure hearing damage in whales
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Hans Thewissen, Northeastern Ohio Universities
Evolution: The Grand Experiment-Official Site | Whale Evolution
Dr. Hans Thewissen, Professor of Anatomy at Northeast Ohio Medical University (NEOMED), is a whale evolution expert.
He is famous for discovering the walking whale Ambulocetus and a nearly complete skeleton of the walking whale Pakicetus (shown in the picture above).
It appeared that Thewissen
had added whale parts (in this case a blowhole) to the areas where he
had no fossil evidence, just as his
former professor had done.
When Dr. Werner began questioning Dr. Thewissen
about the shape of the skull and missing fossil parts, Thewissen
retracted the entire blowhole idea even though he had supplied the world's top museums with skeletons having blowholes.
had reported seven other whale characters of Ambulocetus, but all of these, according to Dr. Werner, are problematic.
said that the cheekbone of Ambulocetus was 'reduced' as in modern whales and dolphins; but, in fact, the cheekbone of Ambulocetus is larger than the cheekbone of a horse.
Finally, according to Dr. Werner, Dr. Thewissen
also retracted his statement that Ambulocetus had a key feature, a whale-like ear bone called a sigmoid process.
Surprisingly, in our interview, Dr. Thewissen
position and suggested that the ear bone of Ambulocetus looked more like a mole rat ear bone.
However, Dr. Zhe-Xi Luo from the Carnegie Museum
and Dr. Thewissen
called the sigmoid process "questionable" and "equivocal."
The three scientists who made the ...
The three scientists who made the discovery, Hans Thewissen, assistant professor of anatomy at Northeastern Ohio Medical School; Tasseer Hussain, professor of anatomy at Harvard University; and M Arif, geologist of the Geological Survey of Pakistan, said in the report in the journal Science (263:312, 1994), "...Ambulocetus represents a critical intermediate between land mammals and marine cetaceans [aquatic mammals like the whale and porpoise]."