Examples of Mesozoic and Cenozoic Bathysiphon (Foraminiferida) from the Pacific Rim and the taxonomic status of Terebellina Ulrich, 1904

Abstract

The generic name Terebellina was proposed by E. O. Ulrich for large (> 100 mm long, several millimeters wide), siliceous, tubular fossils from Cretaceous rocks of southern Alaska. Originally interpreted as annelid tubes, these unusual agglutinated fossils are locally abundant in Triassic to Neogene flysch and other basinal deposits of the Pacific borderlands. Other generic names employed for the same fossils include Torlessia (used in New Zealand) and Yokoia (in Japan). Although most authors have regarded the tubes as body fossils of worms, some workers have speculated recently that Pacific Terebellina are really large bathysiphonid foraminiferids. At the same time, the name has been co-opted by trace fossil workers for thick-walled, grain-lined burrows usually occurring in outer-shelf to slope facies.Based on comparisons with modern and fossil bathysiphonids, including a new species (Bathysiphon harperi) from the Cretaceous of southwestern Oregon, the body fossils called Terebellina are here reinterpreted as large species of Bathysiphon, and the name Terebellina is therefore a junior synonym of this foraminiferid genus. Except for the compression and recrystallization of tubes, Pacific Terebellina resemble very closely the tests of larger species of modern Bathysiphon. Terebellina should not be salvaged for use as an ichnogenus. Most of the trace fossils identified with this name in the recent literature could be accommodated in other established ichnogenera, primarily Palaeophycus (where grain-lined burrows occur individually and are dominantly horizontal) and Schaubcylindrichnus (where they occur in curved bundles).