Orthonychia sp., with openly coiled larval shell; Mississippian (Chesterian) Imo Formation, Arkansas, USA. (A) SNSB-BSPG 2023 I 89. (A1) Apertural view. (A2) Lateral view. (A3) Oblique lateral view on openly coiled protoconch. (B) SNSB-BSPG 2023 I 90. (B1) Lateral view. (B2) Detail initial bulb of protoconch. (B3) Apertural view. (B4) Apical view. (B5) Oblique lateral view.

 
 
  Part of: Nützel A, Ebbestad JO, Seuss B, Munnecke A, Mapes RH, Cook AG (2023) On Paleozoic platycerate gastropods. Zitteliana 97: 29-51. https://doi.org/10.3897/zitteliana.97.115688