Animations show origins of the turtle carapace

The turtle shell (carapace) burst into the evolutionary record over an unusually brief period, and by a very dramatic route – the external repositioning and fusion of the dorsal ribcage. A new series of 3D animations produced by the Laboratory for Evolutionary Morphogenesis show how this occurred by developmental repatterning, and how it makes the turtle skeleton so distinct among vertebrates. (previous work)

The five brief animations depict the following aspects of this intriguing development in evolutionary morphology:

1. Evolutionary changes leading to the turtle shell.

2. Developmental patterning of the modern turtle shell.

3. Generalized developmental patterning of the amniote trunk, showing theropod (bird ancestor) as an example

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4. Anatomy of the ribcage and scapula in the chick

5. Anatomy of the turtle carapace (= ribs) encapsulating the scapula

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