A spiral of teethSourced
The location of this fossil’s tooth spiral was long debated
Helicoprion was a shark-like cartilaginous fish living roughly 290–270 million years ago. Its spiral tooth whorls prompted proposals placing them on jaws, tails or fins. Studies of specimens preserving jaw cartilage indicate a position in the lower jaw.
Finding the teeth did not immediately reveal where they belonged.
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Helicoprion · Wikimedia contributors
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Reviewed: 2026-10-10