Eocene tube-dwelling annelids (Polychaeta: Sedentaria) from the Black Hills, western Washington State: the first record of Neodexiospira from North America

Fossils of two new species of small, dextrally coiled polychaetes, Neodexiospira ferlinghettii and Neodexiospira vanslykei from Eocene strata in the Black Hills southwest of Olympia, Washington State, USA represent the first records of Neodexiospira from North America and the eastern North Pacific Basin. Neodexiospira ferlinghettii occurs in early Eocene sediments within the Crescent Formation near Larch Mountain, and N. vanslykei is found in late Eocene basal sandstone of the Lincoln Creek Formation exposed along Porter Creek. The tubewall of N. vanslykei has two layers: the microstructure of the outer, wider layer consists of tall prismatic crystals radially oriented, and an inner layer consists of larger less defined prismatic crystals oriented perpendicular to the outer layer. In addition, the tracefossil Conchocelichnus was discovered within the tubewalls of some specimens of N. vanslykei , the first record of this ichnogenus from North America.