The dalbergioid legumes (Fabaceae): delimitation of a pantropical monophyletic clade

Abstract

A monophyletic pantropical group of papilionoid legumes, here referred to as the "dalbergioid" legumes, is circumscribed to include all genera previously referred to the tribes Aeschynomeneae and Adesmieae, the subtribe Bryinae of the Desmodieae, and tribe Dalbergieae except Andira, Hymenolobium, Vatairea, and Vataireopsis. This previously undetected group was discovered with phylogenetic analysis of DNA sequences from the chloroplast trnK (including matK) and trnL introns, and the nuclear ribosomal 5.8S and flanking internal transcribed spacers 1 and 2. All dalbergioids belong to one of three well-supported subclades, the Adesmia, Dalbergia, and Pterocarpus clades. The dalbergioid clade and its three main subclades are cryptic in the sense that they are genetically distinct but poorly, if at all, distinguished by nonmolecular data. Traditionally important taxonomic characters, such as arborescent habit, free stamens, and lomented pods, do not provide support for the major clades identified by the molecular analysis. Short shoots, glandular-based trichomes, bilabiate calyces, and aeschynomenoid root nodules, in contrast, are better indicators of relationship at this hierarchical level. The discovery of the dalbergioid clade prompted a re-analysis of root nodule structure and the subsequent finding that the aeschynomenoid root nodule is synapomorphic for the dalbergioids.

A molecular phylogeny reveals the Cuban enigmatic genus Behaimia as a new piece in the Brongniartieae puzzle of papilionoid legumes

“…However, none of the previous studies clearly resolved the position of the Brongniartieae with respect to the other lineages of the Genistoids s.l. (Pennington et al, 2001;Wojciechowski et al, 2004;Cardoso et al, 2012aCardoso et al, , 2013a. Our ML and Bayesian analyses of the broad matK dataset of papilionoid legumes included a denser sampling in the Brongniartieae (63 accessions in 37 species of 13 genera sampled here vs. 18 accessions in 16 species of 10 genera in Cardoso et al, 2013a).…”

“…To accomplish this aim, all major lineages of the papilionoids (Cardoso et al, 2012a(Cardoso et al, , 2013a were included, mostly from previously published matK sequences (e.g., Hu et al, 2000;Lavin et al, 2001Lavin et al, , 2003McMahon and Hufford, 2004;Wojciechowski et al, 2004;Queiroz et al, 2010Queiroz et al, , 2015Queiroz and Lavin, 2011;Delgado-Salinas et al, 2011;Cardoso et al 2012aCardoso et al , 2013aCardoso et al , 2015Snak et al, 2016).…”

“…In the past 15 years, molecular phylogenetic studies have underpinned dramatic taxonomic changes after revealing unexpected relationships, suggesting that floral architecture is relatively labile in the early-branching papilionoid lineages (e.g. Pennington et al, 2001;Wojciechowski et al, 2004; Cardoso et al, 2012aCardoso et al, , 2013aCardoso et al, , 2015Ramos et al, 2016).…”

“…In the past 15 years, molecular phylogenetic studies have underpinned dramatic taxonomic changes after revealing unexpected relationships, suggesting that floral architecture is relatively labile in the early-branching papilionoid lineages (e.g. Pennington et al, 2001;Wojciechowski et al, 2004; Cardoso et al, 2012aCardoso et al, , 2013aCardoso et al, , 2015Ramos et al, 2016).The recent examples of broad phylogenetic re-alignments that were unexpectedly revealed in the early-branching genera of Papilionoideae (Cardoso et al, 2012a(Cardoso et al, , 2012b(Cardoso et al, , 2012c(Cardoso et al, , 2013a(Cardoso et al, , 2017Ramos et al, 2016; Castellanos et al, in press) are not an exception across legumes. For example, dramatic shuffling in the placement of genera has also been necessary within the species-rich canavanine-accumulating clade (Wojciechowski et al, 2004;Silva et al, 2012;Sirichamorn et al, 2012Sirichamorn et al, , 2014Queiroz et al, 2015).…”

Identifying Tertiary Radiations of Fabaceae in the Greater Antilles: Alternatives to Cladistic Vicariance Analysis

“…In addition, all close relatives of both Pictetia and Poitea have been sampled exhaustively. For Pictetia, this includes four other genera in the trans-Atlantic Ormocarpum clade (Diphysa, Zygocarpum, Ormocarpopsis, and Ormocarpum;Lavin et al 2000;Thulin and Lavin 2001) as well as appropriate outgroups identified by Lavin et al (2001). For Poitea, this includes 10 other genera in the primarily North American tribe Robinieae (Hebestigma, Lennea, Gliricidia, Hybosema, Robinia, Poissonia, Coursetia, Olneya, Peteria, Genistidium, and Sphinctospermum;Lavin and Sousa 1995) as well as appropriate outgroups identified in a large-scale legume phylogeny derived from matK sequences (M. F. Wojciechowski, unpublished data).…”