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Monday, November 23, 2009

Photo: Turtles Have Shells Due to Embryo "Origami"


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In humans, the shoulder blade, or scapula, lies over the ribs (left). But in turtles, the ribs have grown over the scapulae to form the reptiles' upper shells.

Although turtles start out with similar bodies to those of mice and chickens, the shells take shape thanks to a unique folding process that happens as turtle embryos mature, researchers said in July 2009.

Illustration courtesy Shigeru Kuratani and Hiroshi Nagashima