Kupeantha (Coffeeae, Rubiaceae), a new genus from Cameroon and Equatorial Guinea.

Martin Cheek,Melanie-Jayne R Howes,Maria G Alvarez-Aguirre,Bonaventure Sonké,Aurélie Grall,Isabel Larridon,Nico Cellinese

doi:10.1371/journal.pone.0199324

Abstract

Two new coffee relatives (tribe Coffeeae, Rubiaceae), discovered during botanical expeditions to Cameroon, are examined for generic placement, and the placement of three previously known species (Argocoffeopsis fosimondi, A. spathulata and Calycosiphonia pentamera) is reinvestigated using plastid sequence (accD-psa1, rpl16, trnL-F) and morphological data. Seed biochemistry of the new species and pollen micromorphology (only one of the two species) are also studied. Based on the plastid sequence data, the new taxa are nested in a well-supported monophyletic group that includes Argocoffeopsis and Calycosiphonia. Within this clade, three well-supported subclades are recovered that are morphologically easy to diagnose: (1) Calycosiphonia (excluding C. pentamera), (2) Argocoffeopsis (excluding A. fosimondi and A. spathulata), and (3) a clade including the above excluded species, in addition to the new species. Based on the results, Kupeantha, a new genus of five species, is described, including two new Critically Endangered taxa from the Highlands of Cameroon: Kupeantha ebo and K. kupensis. Phytochemical analysis of Kupeantha seeds reveals compounds assigned as hydroxycinnamic acid derivatives, amino acids and ent-kaurane diterpenoids; caffeine was not detected. Kupeantha is the first new genus described in tribe Coffeeae in 40 years.

Highlights

Distribution data, important to ensure effective conservation management and sustainable utilisation of natural resources [1], is lacking for many organisms in tropical Africa, including vascular plants necessitating renewed efforts for botanical exploration of the region [2]
The concatenated Maximum likelihood (ML) and Bayesian Inference (BI) analyses did not generate significantly different topologies, we present the relationships shown in the 50% majority consensus multiple-locus BI tree, with the associated posterior probabilities (PP) values and the bootstrap values of the multiple-locus ML tree (Fig 1)
The first of these, the Argocoffeopsis clade (PP = 1, BS = 99) indicated in grey (Fig 1), includes the genus Argocoffeopsis (PP = 1, BS = 86), which becomes monophyletic after exclusion of Argocoffeopsis fosimondi and A. spathulata, the monophyletic genus Calycosiphonia (PP = 1, BS = 87), and a monophyletic group (PP = 0.99, BS = 92) here named Kupeantha comprising Argocoffeopsis fosimondi and A. spathulata in addition to two new species described in this study

Summary

Introduction

Distribution data, important to ensure effective conservation management and sustainable utilisation of natural resources [1], is lacking for many organisms in tropical Africa, including vascular plants necessitating renewed efforts for botanical exploration of the region [2]. Based on the RAINBIO dataset containing 600,000+ georeferenced records representing 22,000+ plant species, priority target areas for future sampling efforts were proposed in Tanzania, Atlantic Central Africa and West Africa [2]. One of the areas, which remained underexplored until recently, is Cameroon in West Central Africa. Kupeantha (Coffeeae, Rubiaceae), a new genus could input the codes provided by the authors and find all the needed information to contact the relevant herbarium

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