A comprehensive sampling of species sheds light on the molecular phylogenetics of Calothecinae (Poaceae, Pooideae): evidence for a new subtribe and multiple genera within the Chascolytrum clade

The circumscription of subtribe Calothecinae has undergone several changes since its description. Currently, three genera are considered in the subtribe: Chascolytrum, Laegaardia and Paramochloa, although no phylogenetic evidence for the placement of the two last genera was published so far. In this study we aim to evaluate the circumscription of Calothecinae and the infrageneric classification recently proposed for Chascolytrum using a more comprehensive sampling of taxa and molecular markers. We included species of all genera of Calothecinae, plus two South American species of Trisetum s.l. that have been suggested to be related to Chascolytrum, and representatives from subtribes Agrostidinae, Echinopogoninae, Brizinae, Torreyochloinae, Phalaridinae and Koeleriinae. We performed Bayesian and Maximum Likelihood analyses using a total of six molecular markers, including four plastid DNA regions (atpF-atpH, matK, rps16 intron, and trnL-trnF) and two ribosomal nuclear regions (ITS and ETS...