The first limbs in Pennsylvania
Where fish grew feet, documented bed by bed
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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.
For children
At a road cut in Pennsylvania lie beds from floodplains where some of the very first animals with limbs and toes lived. They were still mostly fish, but they could lift their heads above water and perhaps crawl through shallows between the reeds.
Sources
- Daeschler, Shubin, Thomson & Amaral, «A Devonian Tetrapod from North America», Science 265 (1994)
- Shubin, Your Inner Fish (2008)
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