Delving deeper into the phylogenetics of the herbaceous bamboos (Poaceae, Bambusoideae, Olyreae): evaluation of generic boundaries within the Parodiolyra/Raddiella clade uncovers a new genus

The present study aims to expand the knowledge of phylogenetic relationships in Olyrinae, a subtribe of herbaceous bamboos (Poaceae: Bambusoideae: Olyreae). Our focus is on Parodiolyra and Raddiella, two historically related genera that, with their sister Diandrolyra, form one of the four main lineages in the subtribe. Previous phylogenetic analyses suggested that Parodiolyra is not monophyletic, but its taxonomic boundaries and its relationship with Raddiella remain uncertain due to low sampling. We increased the taxon sampling and sequenced five regions of the nuclear and plastid genomes for this lineage and other representatives of Olyreae. We used maximum parsimony, maximum likelihood, Bayesian inference and coalescence analysis. Our results corroborate the paraphyly of Parodiolyra, with P. micrantha sister to a clade including the remaining Parodiolyra and Raddiella. All remaining Parodiolyra form a well-supported clade, but Raddiella had conflicting resolutions, being either monophyletic or not. Thus, based on phylogenetic and morphological evidence, we here recircumscribe Parodiolyra, transferring P. micrantha and P. colombiensis to the new genus Taquara (described here). Regarding Raddiella, sampling is still not comprehensive and does not allow a decision on to its taxonomic status to be made at this time. Inclusion of other phreatophytic species may be crucial to resolve the problem of conflicting topologies.