Shells of freshwater limpets

Physical traits identify these snails as native Japanese species, but DNA shows that they are all an invasive species from the United States. Credit: T. Saito et al./Conserv. Genet.

Conservation biology

The invasive snail that fooled zoologists

Genetic study unmasks non-native mollusc marked for protection.

Conservationists have got the wrong snail on their list, according to a genetic analysis.

Takumi Saito at Tohoku University in Sendai, Japan, and his colleagues studied DNA from 66 freshwater limpets — a type of aquatic snail — collected in Japan, Hong Kong, Taiwan, Vietnam and Russia. On the basis of visible traits, each of the individuals was identified as belonging to one of three species considered native to Japan: Gundlachia japonica, Ferrissia nipponica and F. japonica, which is listed by the Japanese government as endangered.

But an evolutionary tree created by the researchers revealed that 54 of the 66 were genetically indistinguishable from the limpet F. californica, a United States native considered an invasive species elsewhere in the world. The remaining 12 were F. nipponica, a true Japanese native.

The authors say that Japanese officials should strike the imposter from the government’s list of threatened and endangered species, and add F. nipponica instead.