The distinctive trace fossil Chubutolithes gaimanensis n. ichnosp. occurs in Casamayoran (early Eocene) and Colhu6haupian (late Oligocene) alluvial rocks of the Sarmiento Formation in eastern Chubut Province, Argentina. Though known for nearly 70 years, its origin has remained obscure. Examination of new specimens and comparisons with modem analogs demonstrate that specimens of Chubutolithes re...
