Appalachian Carboniferous trilobites

Abstract

Trilobites are a relatively rare faunal component in Carboniferous marine strata of the north-central Appalachian Basin. Three of the seven trilobite species known from the Lower Mississippian Waverly Group of Ohio, Griffithidella waverlyensis Hessler, Paladin marginatus (Hyde), and Brachymetopus nodosus Wilson, are monotypic and are known only from the type material. More commonly occurring species include Proetus (Pudoproetus) missouriensis (Shumard) and Breviphillipsia sampsoni (Vogdes), which are present in the Wooster and Meadville Shales and Byers Sandstone. The rare species, Australosutura lodiensis (Meek) and Piltonia eurybathrea (Hessler), are found most commonly in the Wooster and Meadville Shales. At least two species are present in Upper Mississippian strata. Paladin chesterensis (Weller) is found in most Upper Mississippian marine units and ranges through most of the Chesterian. Paladin cf. P. pyriformus Chamberlain is present in a single horizon in the lower Mauch Chunk (lower Chesterian) in southwestern Pennsylvania. Five trilobite species are present in Pennsylvanian strata. Sevillia trinucleata (Herrick) and Sevillia sevillensis Weller are present in upper Atokan and lower Desmoinesian strata of the Pottsville Group of Ohio. Ameura missouriensis (Shumard) first occurs in the Lower Mercer marine horizon (upper Atokan) and ranges to the Ames (Virgilian) marine unit. Ditomopyge scitula (Meek and Worthen), the most pervasive Pennsylvanian trilobite species, ranges from the Lower Mercer (upper Atokan) marine interval into the Portersville (Missourian) marine interval. Ditomopyge decurtata (Gheyselinck) is known only from the Ames marine interval (Virgilian), but may be present in higher marine zones.