Relating to or resembling an archipterygium, the primitive bone structure found in fish fins that may be an evolutionary ancestor of limbs in land animals.
From archipterygium (from Greek archi- 'first, chief' + pterygion 'fin') + -al suffix. The term was coined in the 19th century by anatomists studying fish evolution to describe the ancestral fin structure.
Your arm has bones that trace back to fish fins through this structure—archipterygial anatomy is literally the blueprint evolution used to turn swimming fins into walking legs, and scientists spotted it by comparing fish skeletons to human ones!
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