The frilled dragon exhibits a distinctive large erectile ruff. This lizard usually keeps the frill folded back against its body, but can spread it as a spectacular display to scare off predators. Researchers at the University of Geneva (UNIGE), Switzerland, and the SIB Swiss Institute of Bioinformatics report in the journal eLife that an ancestral embryonic gill of the dragon embryo turns into a neck pocket that expands and folds, forming the frill. The researchers then demonstrate that this robust folding pattern emerges from mechanical forces during the homogeneous growth of the frill skin due to the tensions resulting from its attachment to the neck and head.
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Source: Phys.org