PaleoDB taxon number: 386447
Full reference: R. L. Squires and J. L. Goedert. 1991. New Late Eocene mollusks from localized limestone deposits formed by subduction-related methane seeps, Southwestern Washington. Journal of Paleontology 65(3):412-416
Sister taxon: Pupillaria pupilla
Type specimen: LACMPI 8353, a shell. Its type locality is LACMIP 5802 Bear Creek, which is in a Priabonian marine limestone in Washington.