ammonites
Athyris subquadrata Yang and Xu 1966 (lamp shell)

Rhynchonellata - Athyridida - Athyrididae

Belongs to Athyris according to R. L. Feng and Z. L. Jiang 1978

Sister taxa: Athyris (Cliothyris), Athyris ambiguaeformis, Athyris angulata, Athyris bisulcata, Athyris cestriensis, Athyris damesi, Athyris globularis, Athyris plicatiformis, Athyris sulcata, Athyris xetra

Ecology: stationary low-level epifaunal suspension feeder

Average measurements (in mm): valve 15.7 x 15.4