A taxonomic revision of Aneuraceae (Marchantiophyta) from eastern Africa with an interactive identification key

A taxonomic revision of the liverwort family Aneuraceae in eastern Africa is presented based on the results of an integrative approach. Molecular and morphological data lead to the recognition of fourteen species in eastern Africa, in three genera: eleven species in Riccardia Gray, two in Aneura Dumort. and one in Afroriccardia Reeb & Gradst. One further species, R. multifida, may be expected in eastern Africa and is included in this treatment. Keys, descriptions and illustrations are provided for the accepted species together with data on types, synonymy, geographical distribution, habitat and differentiating characters. A knowledge database was built using Xper3 and an interactive key was generated using the Xper3 platform tools. Riccardia gasparii sp. nov., R. martinii sp. nov. and R. vohimanensis sp. nov. are described as new to science.  A comparison with other regions of the world shows that Africa has relatively few Aneuraceae taxa; only the Holarctic region, with the exception of East Asia, has fewer species. Moreover, dendroid taxa and species with cuticular ornamentation are lacking in Africa. On the other hand, Africa stands out by the presence of the endemic genus Afroriccardia. More collecting is needed in future to clarify the species ranges, the status of questionable taxa and the knowledge of local floras.