1 Thursday Aug 28 2014 10:26 AM/IJPS42308/2014/175/8/jharrell/islesskitain/ritterd//ms review complete/1002/use-graphics/narrow/ default/ Int. J. Plant Sci. 175(8):000–000. 2014.  2014 by The University of Chicago. All rights reserved. 1058-5893/2014/17508-00XX$15.00 DOI: 10.1086/677648 PHYLOGENETIC ANALYSIS OF THE AFRICAN GENUS GILBERTIODENDRON J. LE ´ ONARD AND RELATED GENERA (LEGUMINOSAE-CAESALPINIOIDEAE-DETARIEAE) Manuel de la Estrella, 1, * , † Jan J. Wieringa,‡ Barbara Mackinder,§ Xander van der Burgt,§ Juan A. Devesa,† and Anne Bruneau* *Institut de Recherche En Biologie Ve ´ge ´tale and De ´partement de Sciences Biologiques, Universite ´ de Montre ´al, 4101 Sherbrooke Est, Que ´bec H1X 2B2, Montre ´al, Canada; †Departamento de Bota ´nica, Ecologı ´a y Fisiologı ´a Vegetal, Facultad de Ciencias, Campus de Rabanales, Universidad de Co ´rdoba, 14071 Co ´rdoba, Spain; ‡Naturalis Biodiversity Centre, Botany section, Darwinweg 2, 2333 CC Leiden, The Netherlands; and §Herbarium, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AE, United Kingdom Premise of research. Gilbertiodendron is a genus endemic to Africa with ∼30 species made up of trees of primary dry-land, riverine, and gallery forests. Recently, the west and central African monotypic genus Pellegriniodendron was merged into Gilbertiodendron. Gilbertiodendron is one of 17 genera that form the exclusively African Berlinia clade, and this study presents the findings of a phylogenetic analysis designed to evaluate the generic limits of Gilbertiodendron and its relationships within the Berlinia clade. Methodology. To test the monophyly of Gilbertiodendron and its relationships with other genera, we analyzed nucleotide sequence data from the nuclear ribosomal internal transcribed spacer and the plastid trnL intron and trnL-F intergenic spacer, using parsimony and Bayesian analyses. Pivotal results. Gilbertiodendron is recovered as monophyletic, including all the samples previously rec- ognized as Pellegriniodendron diphyllum. Conclusions. The placement of Pellegriniodendron in synonymy with Gilbertiodendron is supported by our results. Our analyses suggest that G. diphyllum is the same taxon on both sides of the Dahomey Gap. The G. ogoouense complex is a monophyletic group of species that needs a new taxonomic framework and within which several new species will be described. The phylogenetic framework presented here and the ongoing taxonomic revision should provide the baseline data required for adequate assessment of this group of tree species, of which only eight have been assessed under the International Union for Conservation of Nature’s Red List criteria. Keywords: Didelotia, Fabaceae, ITS, Librevillea, Plagiosiphon, Pellegriniodendron, phylogenetic analyses, tropical Africa, trnL-trnF. Introduction Leguminosae is the third-largest flowering plant family, made up ∼19,500 species in ∼751 genera, occurring in a great variety of habitats from rain forests and mangrove swamps to deserts and temperate zones (Lewis et al. 2005; LPWG 2013a). The family is traditionally divided into 3 subfamilies—Papil- ionoideae, Mimosoideae, and Caesalpinioideae—but propos- als for a new classification currently being discussed will in- crease that number to 6, 10–12, or even 15 (LPWG 2013b). The caesalpinioid legumes form the smallest of the three tra- ditionally recognized subfamilies and includes ∼2,250 species assigned to 171 genera and four tribes (Lewis et al. 2005; LPWG 2013a). In terms of species richness, Leguminosae is the most important angiosperm family in tropical Africa (Le- brun and Stork 1998). The dominance of Caesalpinioideae species in tropical Africa was recognized by Letouzey (1968), who named a specific forest type, the fore ˆt biafre ´enne. Cae- salpinioideae species can form large expanses of forests, some 1 Author for correspondence; e-mail: mdelaestrella@gmail.com. Manuscript received January 2014; revised manuscript received May 2014; elec- tronically published August xx, 2014. dominated by a single tree species (e.g., Gilbertiodendron dew- evrei monodominant forest; Corlett and Primack 2011). About half of all caesalpinioid genera (82 of 171) belong to the mono- phyletic tribe Detarieae (Bruneau et al. 2008), which is pan- tropical in distribution, but the majority of the genera are confined to Africa and Madagascar (Mackinder 2005). One consistently reported group within the Detarieae is the African Berlinia clade (Bruneau et al. 2008), which is made up of 17 genera of medium to large trees. This clade includes a weakly supported group made up of Didelotia, Plagiosiphon, Librev- illea, and Gilbertiodendron, sister to a large clade that includes Anthonotha, Englerodendron, Oddoniodendron (recently re- viewed by Breteler 2006, 2008, 2010, 2011), Berlinia, Isob- erlinia, Microberlinia (Mackinder and Pennington 2011), and the ‘‘Babijt’’ group; the latter, as delimited by Wieringa and Gervais (2003), includes Brachystegia, Aphanocalyx, Bikinia, Julbernardia, Icuria, and Tetraberlinia. Many of the tree spe- cies in the African forests belong to the Berlinia clade, and this is the most important group of trees in the lowland evergreen rainforest (Wieringa 1999) and a dominant component of Af- rican tropical forests (White 1983). Gilbertiodendron is an endemic African genus with ∼30 spe- cies and a dominant component in many African forests. All q1