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The first limbs in Pennsylvania

365.0 million yrs ago · na-red-hill

Red Hill in Pennsylvania is a road cut exposing Devonian floodplains, the period in which the first vertebrates with limbs and toes appear. Red Hill has yielded Hynerpeton and Densignathus, and the locality is unusual in preserving the whole ecosystem around the transition — plants, fish, arthropods — rather than only the spectacular skeletons. The same transition was later documented still more clearly by Tiktaalik from Ellesmere Island in Arctic Canada, found in 2004 after a deliberate search in beds of exactly the right age and type.

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