Sirdavidia, an extraordinary new genus of Annonaceae from Gabon.

Thomas L P Couvreur,Raoul Niangadouma,Bonaventure Sonké,Hervé Sauquet

doi:10.3897/phytokeys.46.8937

Abstract

A distinctive new monotypic genus from Gabon is described in the tropical plant family Annonaceae: Sirdavidia, in honor to Sir David Attenborough. Molecular phylogenetic analyses confirm that Sirdavidia, which is very distinct from a morphological standpoint, is not nested in any existing genus of Annonaceae and belongs to tribe Piptostigmateae (subfamily Malmeoideae), which now contains a total of six genera. The genus is characterized by long acuminate leaves, fully reflexed red petals, 16–19 bright yellow, loosely arranged stamens forming a cone, and a single carpel topped by a conspicuous stigma. With just three known collections, a preliminary IUCN conservation status assessment is provided as “endangered” as well as a distribution map. The discovery of Sirdavidia is remarkable at several levels. First, it was collected near the road in one of the botanically best-known regions of Gabon: Monts de Cristal National Park. Second, its sister group is the genus Mwasumbia, also monotypic, endemic to a small area in a forest in Tanzania, some 3000 km away. Finally, the floral morphology is highly suggestive of a buzz pollination syndrome. If confirmed, this would be the first documentation of such a pollination syndrome in Magnoliidae and early-diverging angiosperms in general.

Highlights

The Central African country of Gabon is merely 270 000 km2 in size, but is home to an incredible botanical diversity (Sosef et al 2006)
Sirdavidia solannona is nested in Piptostigmateae with strong support and is sister to Mwasumbia alba Couvreur & Johnson (MP-BS = 95%; ML-BS = 97%)
The molecular phylogenetic analyses presented here confirms that Sirdavidia solannona belongs to tribe Piptostigmateae, which contains a total of six accepted genera

Summary

Introduction

The Central African country of Gabon is merely 270 000 km in size, but is home to an incredible botanical diversity (Sosef et al 2006). Around 82% of its territory is covered with tropical rain forest and with around 5000 vascular plant species, Gabon is an important center of plant biodiversity in Central Africa (Sosef et al 2006). With around 2500 species (Chatrou et al 2012; Couvreur et al 2011) it is one of the most diverse plant families in tropical rain forests, and the largest in order Magnoliales (Haywood et al 2009). A new phylogenetic classification of the family recognizes four subfamilies and 14 tribes (Chatrou et al 2012). This was followed by a scratchpad website (World Annonaceae; Couvreur 2014b) documenting Annonaceae diversity and taxonomy worldwide. From Central Africa, and in particular Gabon, have been rarer with only a few such descriptions (Jongkind 2002)

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Conclusion