Small problematic phosphatic sclerites from the Ordovician of Iapetus

Abstract

Problematic sclerites are common in Cambrian rocks around the world, but much less so in those of the Ordovician. Eurytholia prattensis new genus and species and E. elibata new species, described herein, are rare but widely distributed faunal elements in a narrow stratigraphical interval (Pygodus serra and P. anserinus conodont biozones) within Ordovician beds in an area bordering Iapetus (South Wales, UK; Alabama, USA; Dalarna, Sweden; and North Estonia). Specimens are minute plates (usually less than 1 mm wide), transversely ovoid, and hollow. They are not closely comparable with any previously described fossils. Eurytholia plates are interpreted as dorsal dermal sclerites from an animal of uncertain affinities. The scleritome is provisionally reconstructed as ovoid in form, with sclerites arranged in sub-longitudinal rows.