The Diamond Coal Mine of Linton, Ohio, and its Pennsylvanian-age vertebrates

Abstract

The village of Linton in Jefferson County, Ohio, was the site of the Ohio Diamond Coal Mine, a drift mine exploiting the Upper Freeport coal of the Allegheny Group, Middle Pennsylvanian (equivalent to late Westphalian D, Upper Carboniferous). Beginning in 1856, extensive collecting from the cannel underlying the coal has yielded a diverse assemblage of nearly 40 vertebrate genera making Linton the most prolific Upper Carboniferous vertebrate locality in the world. Examination of over 6000 Linton specimens indicates that fish remains are approximately ten times more abundant than tetrapods, with coelacanths, haplolepid palaeoniscoids, and xenacanth sharks predominating. The most common tetrapods are small aquatic amphibians, including urocordylid and keraterpetontid nectrideans, trimerorhachoid and colosteoid temnospondyls, aïstopods, and lysorophid microsaurs. Other amphibian and reptilian genera are exceedingly rare and show more terrestrial adaptations, suggesting that they were biological transients within an otherwise aquatic biocoenose.