Phylogenetic Analysis of the African Genus Gilbertiodendron J. Léonard and Related Genera (Leguminosae-Caesalpinioideae-Detarieae)

Abstract

Editor: Patrick S. HerendeenPremise 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 recognized 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.

On the Monophyly ofMacrolobiumSchreb., an Ecologically Diverse Neotropical Tree Genus (Fabaceae-Detarioideae)

“…Cowan by Redden et al (2010). Although the Brownea clade was strongly supported (Bruneau et al 2008;de la Estrella et al 2017), some of the constituent genera, including Macrolobium, were not monophyletic or appeared poorly resolved in these studies (e.g., Bruneau et al 2008;de la Estrella et al 2017).…”

“…For the most recalcitrant samples, the Qiagen DNeasy Plant Mini Kit (Qiagen, Manchester, UK) was used according to the manufacturer's instructions. PCR amplifications and cycle sequencing were performed as described by de la Estrella et al (2017), with nested amplifications used for difficult samples as described in that study and references therein, but also using the internal ITS primers ITS2 and ITS3 (White et al 1990). Cloning was not performed, as double peaks were not common in the resulting chromatograms and polyploidy has not been reported in the genus.…”

“…the ITS marker (although with limited species-level sampling) also found Macrolobium to be monophyletic (Redden et al 2010;de la Estrella et al 2017). The monophyly of Macrolobium is an important finding because it is the most speciesrich genus in subfamily Detarioideae after Cynometra, which has been revealed as paraphyletic (de la Estrella et al 2017;Radosavljevic et al, forthcoming). The degree of morphological and ecological variation within Macrolobium also makes monophyly noteworthy (Cowan 1953;Berry et al 1995;Mackinder et al 2005).…”

“…The latter has repeatedly been found to be the most abundant and species-rich Neotropical plant family (Valencia 1994;Burnham and Johnson 2004;ter Steege et al 2013ter Steege et al , 2016. Within the new six-subfamily arrangement of the family (LPWG 2017), Macrolobium is the most species-rich genus within the Detarioideae, after the apparently paraphyletic Cynometra (de la Estrella et al 2017;Radosavljevic et al, forthcoming).…”

“…The Detarioideae (or Detarieae) has been the focus of several studies in recent years (e.g., Bruneau et al 2001Bruneau et al , 2008Bruneau et al , 2014Fougère-Danezan et al 2007Redden et al 2010;de la Estrella et al 2014de la Estrella et al , 2017. Contrary to Cowan's (1953) and Cowan and Polhill's (1981) Macrolobium group hypothesis, Bruneau et al (2001) found Macrolobium not closely related to African genera but part of a Brownea clade with five other endemic Neotropical genera (Brownea Jacq., Browneopsis Huber, Paloue Aubl., Elizabetha Schomb.…”