In the September 21 issue of the journal Science, Rose provides outside perspective on a report in the same issue that fills an important gap in scientists' understanding of whale evolution. The report by others documents new fossils of very primitive whales that were found in Pakistan.
The new fossils, says Rose, have well-developed limbs and are the first to have well-enough preserved ankle bones to allow scientists to change their conclusions about which animals are the closest relatives of these 50 million-year-old primitive whales. The importance of this finding, and a similar report about even older fossils in the September 20 issue of Nature, is that it unifies the scientific perspective on whale evolution, says Rose.
"What's most important about these new fossils is that they contain well-preserved ankles, the most important region morphologically for establishing evolutionary relationships as early whales were in the process of becoming aquatic," explains Rose. "Previously, only fragments have been known of these species, and the few ankle bones that some had identified were not widely accepted among scientists because of the condition of the fossils and their lack of direct association with whale skulls."
There are two main ways scientists determine evolutionary relationships among various species, he explains. Some scientists consider physical characteristics of specimens -- the morphology -- and look for similarities or differences, the pres
Contact: Joanna Downer
Johns Hopkins Medical Institutions