title: Bricklebush (Brickellia) phylogeny reveals dimensions of the great Asteraceae radiation in Mexico.
abstract: Data from molecular phylogenetics were used to assess aspects of diversity and relationships in Brickellia, a large and widespread genus of Eupatorieae. The dataset included sequence data from nuclear ribosomal ITS, ETS, and plastid psbA-trnH regions. An initial question was to assess the monophyly of the genus and whether Barroetea, Phanerostylis, and Kuhnia should be recognized as separate from or included in Brickellia. The results supported the hypothesis that Brickellia is monophyletic, with the small (2-3 species) Pleurocoronis as the sister group and showed Barroetea, Phanerostylis, and Kuhnia all embedded within the genus. Results of a time calibrated phylogeny from a BEAST analysis gave an estimated origination time for Brickellia at about 9 million years ago (Ma), with the oldest split within the genus dated at about 7.5Ma. A BAMM analysis based on the time calibrated tree showed that Brickellia has one rate shift in diversification associated with its origin in the late Miocene. Some lineages within the genus have had an increase in the rate of diversification over the past 5Ma, whereas other lineages have had a decrease in net diversification during this period. The results also elucidated nine clades within Brickellia which are accepted as taxonomic sections, and that will form logical units for future detailed studies.
authors.affiliation: Department of Ecology & Evolutionary Biology, University of Tennessee, Knoxville, TN 37996, USA. Electronic address: eschilling@utk.edu.
authors.forename: Edward E
authors.initials: EE
authors.lastname: Schilling
authors.affiliation: Section of Integrative Biology, University of Texas, 1 University Station C0930, Austin, TX 78712, USA.
authors.forename: Jose L
authors.initials: JL
authors.lastname: Panero
authors.affiliation: P.O. Box 8315, Santa Fe, NM 87504, USA.
authors.forename: Bonnie S
authors.initials: BS
authors.lastname: Crozier
authors.affiliation: Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA.
authors.forename: Randall W
authors.initials: RW
authors.lastname: Scott
authors.affiliation: Laboratorio de Recursos Naturales, Tecnología y Prototipos, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Unidad de Biología, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla C.P. 54090, Estado de México, Mexico.
authors.forename: Patricia
authors.initials: P
authors.lastname: Dávila
mesh_terms: D019659:Asteraceae / Q000145:classification* / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000235:genetics; D019143:Evolution, Molecular; D008800:Mexico; D010802:Phylogeny; D018087:Plastids / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D018744:DNA, Plant; D021903:DNA, Ribosomal Spacer
keywords: Eupatorieae; Mexican biodiversity; Rate shifts in net diversification; Sonoran Desert; Time calibrated phylogeny