Architectonicidae, common name the staircase shells or sundials, are a family of sea snails, marine gastropod mollusks in the informal group "Lower Heterobranchia" (= Allogastropoda) of the clade Heterobranchia. The extinct families † Amphitomariidae Bandel, 1994 and † Cassianaxidae Bandel, 1996 belong to the same superfamily.
Species taxanomy provided by GBIF Secretariat (2022). GBIF Backbone Taxonomy. Checklist dataset https://doi.org/10.15468/39omei accessed via GBIF.org on 2023-06-13; License: CC BY 4.0