On Paleozoic platycerate gastropods Author Nuetzel, Alexander https://orcid.org/0000-0002-8852-7688 SNSB-Bayerische Staatssammlung fuer Palaeontologie und Geologie, Richard-Wagner-Str. 10, 80333 Muenchen, Germany & Department of Earth and Environmental Sciences, Paleontology and Geobiology, Ludwig-Maximilians-Universitaet Muenchen, Richard-Wagner-Str. 10, 80333 Muenchen, Germany nuetzel@snsb.de Author Ebbestad, Jan Ove https://orcid.org/0000-0001-8769-3572 GeoBio-Center, Ludwig-Maximilians-Universitaet Muenchen, Richard-Wagner-Str. 10, 80333 Muenchen, Germany Author Seuss, Barbara https://orcid.org/0000-0001-6615-8108 Museum of Evolution, Uppsala University, Norbyvaegen 16, SE 75236 Uppsala, Sweden Author Munnecke, Axel https://orcid.org/0000-0002-6898-1082 Museum of Evolution, Uppsala University, Norbyvaegen 16, SE 75236 Uppsala, Sweden Author Mapes, Royal H. Friedrich-Alexander-Universitaet Erlangen-Nuernberg, GeoZentrum Nordbayern, Loewenichstrasse 28, 91054 Erlangen, Germany Author Cook, Alex G. Division of Paleontology, American Museum of Natural History, Central Park West at 79 th Street, New York, NY, 10024, USA text Zitteliana 2023 2023-12-12 97 29 51 http://dx.doi.org/10.3897/zitteliana.97.115688 journal article http://dx.doi.org/10.3897/zitteliana.97.115688 2747-8106-97-29 BA2DA07949064AC8AE1105E21BBF12B9 CA664780046A5F938793904BB13AEB75 Family Orthonychiidae Bandel & Fryda , 1999 Remarks. Bandel and Fryda (1999) erected this family for limpet-shaped Paleozoic gastropods formerly included in Platyceratidae . Based on the openly coiled fishhook-like protoconch of the Pennsylvanian limpet-shaped species Orthonychia parva (Swallow, 1858 in Shumard and Swallow), they placed Orthonychiidae in their new order Cyrtoneritimorpha . However, the protoconch of the Devonian type species of Orthonychia is yet unknown (see Knight 1941 ). The Ordovician family Pollicinidae resembles some members of Orthonychiidae but these shells are bilaterally symmetrical and their early ontogeny is largely unknown (see Peel 2020a , b ).