Nothodissotis (Melastomataceae), a new genus from Atlantic Central Africa, including the new species N. alenensis from Equatorial Guinea

Abstract

Based on morphological and phylogenetic evidence, a new genus of Melastomataceae (Melastomateae), Nothodissotis Veranso-Libalah & G.Kadereit, gen. nov., is described from Atlantic Central Africa. Nothodissotis is distinguished from other African Melastomateae genera by its calyx-lobes that are notched at apex and asymmetrical (vs. entire and symmetrical). Nothodissotis includes two species: the type species N. barteri (Hook.f.) Veranso-Libalah & G.Kadereit, comb. nov. (syn. Dissotis barteri Hook.f.), and the new species N. alenensis Veranso-Libalah & O. Lachenaud, sp. nov., described and illustrated here. Both species are restricted to open vegetation on rock outcrops within the forested region of Atlantic Central Africa. Nothodissotis barteri has a scattered distribution in Cameroon, Equatorial Guinea, Gabon and Príncipe Island, while N. alenensis is endemic to the Monte Alén massif in Equatorial Guinea, an area where N. barteri does not occur. Nothodissotis alenensis differs from N. barteri by its hypanthium bearing sessile appendages with penicillate hairs (vs. stalked stellate appendages) and its staminal appendages that are much smaller in antepetalous than in antesepalous stamens (vs. subequal in all stamens). The conservation status of both N. barteri and N. alenensis is assessed as Vulnerable in accordance with IUCN criteria.