Abstract— In North America, the tribe Vernonieae (Asteraceae) comprises 92 species distributed mainly in mountain ranges. Combining molecular data for 62 species and herbarium records (N = 5424), spatial phylogenetics was used to identify regions of high phylodiversity, centers of endemism, and patterns of phylogenetic turnover in North America. The study region was divided into 1° latitude and longitude grid cells; four molecular markers (ndhF, trnL, rpl32-trnL, and ITS) were used to construct a phylogram and alpha phylodiversity indices were calculated (phylogenetic diversity and relative phylogenetic diversity) along with categorical analysis of neo- and paleo-endemism (CANAPE). Beta phylodiversity was examined using the PhyloβSimpson and PhyloβRWTurnover indices to determine major phyloregions. A randomization test of phylogenetic diversity revealed phylogenetic clustering in the north and south of North America, while overdispersion was concentrated in the south. Relative phylogenetic diversity showed significant concentrations of long branches in the north and south, whereas central Mexico exhibited concentrations of short branches. The CANAPE analysis revealed centers of paleo-endemism in southeastern Mexico, with long-branching lineages in genera such as Cyrtocymura and Lepidonia . Neo-endemism centers with short-branching species, such as those in genera Eremosis and Vickianthus were also identified, as well as areas with mixed endemism in different regions of Mexico. Phylogenetic turnover patterns determined 16 phyloregions (PhyloβSimpson) and 17 phyloregions (PhyloβRWTurnover).
Morales-Garduño et al. (Wed,) studied this question.