Rhynchonellata - Athyridida - Athyrididae

Alternative combinations: Athyris subtilita, Spirigera subtilita, Terebratula subtilita

Full reference: J. Hall. 1852. Notes on some of the fossils collected on the route from the Missouri River to the Great Salt Lake and in the vicintiy of the latter place. Exploration and survey of the valley of the Great Salt Lake of Utah. U. S. 32nd Congress Special Session, S. Ex. Doc. 3:407-414

Belongs to Composita according to M. R. Mudge et al. 1962

Sister taxa: Athyris (Composita) indosinensis, Athyris (Composita) semirostrata, Composita advena, Composita affinis, Composita apheles, Composita apsidata, Composita bamberi, Composita biforma, Composita bucculenta, Composita costata, Composita cracens, Composita crassa, Composita depressa, Composita discina, Composita elongata, Composita emarginata, Composita enormis, Composita grandis, Composita hapsida, Composita huagongensis, Composita idahoensis, Composita imbricata, Composita jogensis, Composita longa, Composita mexicana, Composita minuscula, Composita mira, Composita misriensis, Composita nucella, Composita ovata, Composita parasulcata, Composita pilula, Composita plana, Composita prospera, Composita pyriformis, Composita quadrirotunda, Composita quantilla, Composita rotunda, Composita sigma, Composita stalagmium, Composita strongyle, Composita subcircularis, Composita subquadrata, Composita subtriangularis, Composita tareica, Composita tetralobata, Composita tobaensis

Ecology: stationary low-level epifaunal suspension feeder

Average measurements (in mm): shell 9.87 x 9.17, valve 27.4 x 30.6