Filling in the gaps of the papilionoid legume phylogeny: The enigmatic Amazonian genus Petaladenium is a new branch of the early-diverging Amburaneae clade

Abstract

Recent deep-level phylogenies of the basal papilionoid legumes (Leguminosae, Papilionoideae) have resolved many clades, yet left the phylogenetic placement of several genera unassessed. The phylogenetically enigmatic Amazonian monospecific genus Petaladenium had been believed to be close to the genera of the Genistoid Ormosieae clade. In this paper we provide the first DNA phylogenetic study of Petaladenium and show it is not part of the large Genistoid clade, but is a new branch of the Amburaneae clade, one of the first-diverging lineages of the Papilionoideae phylogeny. This result is supported by the chemical observation that the quinolizidine alkaloids, a chemical synapomorphy of the Genistoids, are absent in Petaladenium. Parsimony and Bayesian phylogenetic analysis of nuclear ITS/5.8S and plastid matK and trnL intron agree with a new interpretation of morphology that Petaladenium is sister to Dussia, a genus comprising ∼18 species of trees largely confined to rainforests in Central America and northern South America. Petaladenium, Dussia, and Myrospermum have papilionate flowers in a clade otherwise with radial floral symmetry, loss of petals or incompletely differentiated petals. Our phylogenetic analyses also revealed well-supported resolution within the three main lineages of the ADA clade (Angylocalyceae, Dipterygeae, and Amburaneae). We also discuss further molecular phylogenetic evidence for the undersampled Amazonian genera Aldina and Monopteryx, and the tropical African Amphimas, Cordyla, Leucomphalos, and Mildbraediodendron.

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

“…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).…”

Flower development ofGoniorrhachis marginatareveals new insights into the evolution of the florally diverse detarioid legumes

“…Hardwickia binata EU361967 Cardoso et al (2015). Here we highlight the placement of G. marginata in the close-up phylogeny of the caesalpinioid Detarieae.…”

“…To avoid the possible use of misidentified or inaccurate sequences, we included only our own previously generated sequences (e.g. Cardoso et al, 2012aCardoso et al, , 2015 or those from comprehensive phylogenetic analyses of legumes (e.g. Wojciechowski et al, 2004;Bruneau et al, 2008).…”