Abrodictyum inexpectatum, an unexpected new fern species (Hymenophyllaceae, Polypodiidae) for Madagascar, as revealed by an integrative approach

Abstract

The fern genus Abrodictyum (Hymenophyllaceae) is thought to have at least seven species in the Afro-Malagasy region. But morphological re-examination of uncommon specimens, comparison with supposedly related taxa, and a new molecular phylogenetic analysis clearly led to recognize an additional species for Madagascar. We here describe this new species as Abrodictyum inexpectatum sp. nov. Morphologically, the new species differs from the closely related and sympatric A. franceae by its smaller size, narrower ultimate segments and the plane fronds in the wild, vs. crispate for A. franceae. We provide a modified key to all eight species of Abrodictyum now recognized in the Afro-Malagasy region.