†Mya (Antiguamya) Effinger 1938 (softshell clam)
Full reference: W. L. Effinger. 1938. The Gries Ranch Fauna (Oligocene) of Western Washington. Journal of Paleontology 12(4):355-390
Parent taxon: Mya according to W. L. Effinger 1938
Sister taxa: Mya (Arenomya), Mya (Geramya), Mya (Mya), Mya convexa, Mya cuneiformis, Mya dilata, Mya ilyinensis, Mya kovatschensis, Mya majanatschensis, Mya montereyana, Mya producta, Mya sachalinensis, Mya schweinfurthi, Mya simplex, Mya tigilensis, Mya virgo, Mya wilsoni
Subtaxa: Mya (Antiguamya) arnoldi
Type: Saxicava arnoldi
Ecology: facultatively mobile infaunal suspension feeder
Distribution:
• Eocene of United States (2: Washington collections)
Total: 2 collections each including a single occurrence