SCORPION REMAINS IN A PENNSYLVANIAN CAVE DEPOSIT

The extensive fossil record found in cave deposits was recognized as long ago as 1821 by Buckland, who studied bones and teeth from caves in England and continental Europe. Since that time, numerous rich vertebrate faunas, especially Quaternary biotas, have been described from caves worldwide. In contrast, the invertebrate and plant record, especially that from older karst deposits, has been relatively ignored. A recently described Middle Pennsylvanian (Atokan; Westphalian C) paleokarst system near Morris, Illinois has an abundant palynoflora and superb examples of charcoalified wood, seeds, and leaves. These include remains of lycopods, suggestive of moist conditions, as well as early conifers and cordaites, indicative of a local well drained environment. Taphonomy of the plant remains and the presence of diagnostic aromatic and polyaromatic hydrocarbons indicate frequent wildfires. The only animal remains discovered to date are those of terrestrial arthropods, including scorpions. The material consists mainly of minute pieces of cuticle, which retain their original flexibility and color. As pointed out by Jeram (1994), scorpion cuticle appears particularly resistant to decay. Most fragments are not diagnostic as to body region, although they may include a telson. These remains date from an important period in the evolution of scorpions, corresponding to the appearance of the stem group (Paleaosterni) of modern scorpions (Neoscorpiones) and just predating the earliest orthostern neoscorpions (Jeram 1994; Dunlop et al. 2007). Additional material will be required to assign then to the Neoscorpriones or the contemporaneous Mesoscorpionina.