The type species of the genus is fossil
Ptychalaea flexidens (Reuss, 1861) from
Miocene of
Europe. In 1920 the extant snails from
Japan were placed into
Ptychalaea -
Nesopupa dedecora Pilsbry, 1902 and its form
Nesopupa tamagonari Pilsbry, Hirase, 1904. Japanese species was established under the name
Ptychalaea dedecora (Pilsbry, 1902). Although in 2018 it was shown that
Nesopupa dedecora and its form
Nesopupa tamagonari belong to genus
Vertigo (
Vertiginidae) and on this basis it was erroneously concluded by J.C. Nekola with coauthors that
Ptychalaea is synonym of
Vertigo. Although in fact it only means that
Nesopupa dedecora is not a species of
Ptychalaea and there should be no consequence for taxonomic status of this genus. The type species of
Ptychalaea,
Ptychalaea flexidens from
Miocene of
Europe, is probably not related to extant
Nesopupa dedecora from
Japan. == References ==