The primitive silverfish Tricholepidion gertschi Wygodzinsky has traditionally been considered to be the sole surviving member of the family Lepidotrichidae, originally described from a middle Eocene fossil in Baltic amber. The fossil species, however, possesses apomorphic traits uniting it with more typical Zygentoma, and Lepidotrichidae in the traditional sense is grouped solely on plesiomorphic features. Tricholepidion is a relic of a more ancient diversification than Lepidotrichidae or even Lepidotrichidae Euzygentoma (= Neozygentoma). Tricholepidion is therefore segregated into a separate family, Tricholepidiidae, familia novum, and Lepidotrichidae is restricted to Lepidothrix in Baltic amber.