Two new species of Raphia (Palmae/Arecaceae) from Cameroon and Gabon

Abstract

Raphia (Arecaceae, Calamoideae) is the most diverse genus of African palms with around 20 species. Two new species from Cameroon and Gabon, Raphiagabonica Mogue, Sonké & Couvreur, sp. nov. and Raphiazamiana Mogue, Sonké & Couvreur, sp. nov. are described and illustrated. Their affinities are discussed and the conservation status of each species is assessed. For both species, distribution maps are provided. Raphiagabonica is restricted to two small populations from central Gabon, where it occurs on hillsides on tierra firme soil, and close to small streams. Its preliminary IUCN status is Endangered, being amongst the five most threatened palm species in Africa. Raphiagabonica potentially belongs to the moniliform section. Raphiazamiana is largely distributed from south Cameroon to south Gabon and is very common. It is also a multi-used palm, from which wine, grubs and construction material are extracted and sold. It generally occurs in large stands in a wide range of ecosystems such as swamps, coastal forests on partially inundated sandy soils and inundated savannahs. Its large stature, hard to access habitat (swamps) and abundant presence might have discouraged botanists to collect it until now. Raphiazamiana belongs to the taxonomically complex raphiate section.

Unravelling the Phylogenomic Relationships of the Most Diverse African Palm GenusRaphia(Calamoideae, Arecaceae)

“…Raphia zamiana was recently described [7]. Our broad sampling of this species, however, recovers R. zamiana as polyphyletic, with individuals grouping into two main clades, flagged as two different species by our species delimitation analysis (Figures 1, A2).…”

“…This section remains the same as defined by Otedoh [21]. We also include the newly described species R. gabonica [7] in this section. A section with four recognized species: R. gabonica, R. hookeri, R. sese and R. rostrata . Section Raphiate Otedoh. Type species: R. palma-pinus (Gaertn.)…”

“…This section remains the same as defined by Otedoh [21]. We also include the newly described species R. gabonica [7] in this section.…”

“…We sampled a total of 56 individuals (see A1 for details) representing 18 out of the 21 species accepted to date [7,19] and representing all sections described by Otedoh [21]. In order to collect proper material for sequencing, several field trips were undertaken across several African countries including Ivory Coast, Ghana, Gabon, Cameroon, Angola and the Demographic Republic of the Congo between 2012 and 2017.…”

“…Among African palms, the genus Raphia (subfamily Calamoideae, tribe Raphiaeae) is the most species rich, with 21 species described to date [2,7]. Of these, one, R. taedigera , is endemic to the Neotropics, with a disjunct distribution in Brazil and central America.…”