Solving The Mystery Of Turtle Shells
The long-standing mystery of how the turtle got its shell may have been solved by a Japanese study.
The paper, published today in the journal Science, shows the outer shell of turtles develop from the ribs and backbone and not from the skin.
The findings also demonstrate that the evolution of the turtle shell is not as complex as many previously believed.
Dr Hiroshi Nagashima and colleagues at the RIKEN Centre for Developmental Biology in Kobe, examined the muscular and skeletal changes during a modern turtle's embryonic development.
They compared the embryo of the Chinese soft-shelled turtle (Pelodiscus sinensis) with embryos of the chicken (Gallus gallus) and the mouse (Mus musculus).
Co-author Dr Rolf Ericsson, now of the School of Biological Sciences at Macquarie University in Sydney, says the three embryos have the same developmental pattern, likely to have been shared with their last common ancestor.
"At early development [the turtle embryo] looks exactly like a bird or mouse," he says.
However, at approximately one-third of the way through incubation, it "begins to develop specific turtle morphology," says Ericsson.
