摘要:Fenestellaceae is a poorly known family which comprises the genera Fenestella , Lojkania and Pleurostromella . There is limited molecular data or modern taxonomic descriptions for taxa of these genera. We therefore loaned the type and other specimens of Fenestella princeps and Lojkania hungarica from herbaria worldwide to clarify the morphological characters of Fenestella and Lojkania . A circumscription of the type species, Fenestella princeps and Lojkania hungarica is provided. Fenestella faberi and F. fenestrata have also been studied and are described and discussed. Lojkania is excluded from Fenestellaceae based on morphology and tentatively placed in Testudinaceae . In the study, we maintain the family Fenestellaceae until the type species is recollected and molecular phylogeny is used to confirm its natural placement