Systematic position and composition of the superfamily Notanoplioidea Gill, 1969 (Brachiopoda, Articulata)

The systematic position of several genera of articulate brachiopods grouped around Notanoplia Gill is controversial. Notanoplia was established in 1950 within the order Chonetida; this genus and several externally similar genera, which were established later, were referred by different authors to the orders Orthida, Strophomenida, Chonetida, Atrypida, Spiriferida, or considered as incertae sedis. The morphological analysis of the shell of Notanoplia and the related genera Boucotia and Costanoplia supports the placement of these genera in a separate superfamily, Notanoplioidea, within the order Strophomenida. Other genera similar in the shell outline and shape to Notanoplia and conditionally considered as related to it probably belong to other strophomenid superfamilies or other orders.