On the invalidity of Halitherium schinzii Kaup, 1838 (Mammalia, Sirenia), with comments on systematic consequences

摘要

The holotype of the sirenian species Halitherium schinzii Kaup, 1838 from the Alzey Formation (early Oligocene) of the Mainz Basin, western Germany, is reviewed in detail and revised. It is concluded that the type specimen, an isolated premolar, is non-diagnostic, because it reveals no characters of taxonomic value. Therefore, the taxon name H. schinzii is regarded as a nomen dubium, thus cannot be applied to any currently proposed sirenian species. The name of the genus “Halitherium”, which is based on the type species “H. schinzii”, cannot be applied to other species previously assigned to congeneric taxa. Consequently, taxonomic and systematic re-assessment is required. Due to the fact that “Halitherium” is the taxonomical basis of the Halitheriinae, conclusions are drawn on the inappropriateness of this subfamily.