Abstract Detail



Biogeography

Lichter Marck , Isaac H [1], Baldwin, Bruce [1].

Historical biogeography of the rock daisies (tribe Perityleae; Asteraceae) in the sky island archipelagos of the southwest U.S. and northern Mexico.

Understanding the origins of the endemic flora of sky islands in desert seas requires integrating evolutionary and biogeographic perspectives from arid and oceanic island systems. The rock daisies (Perityleae; Asteraceae) constitute a tribe of ca. 75 species of herbs and shrubs that have been considered a remarkable example of geographic speciation in the sky islands of the southwest U.S. and northern Mexico. We present results from a next-generation sequencing project, specifically using genome skimming, to infer the first densely sampled molecular phylogeny of Perityleae. Our dated phylogenetic tree tests for timing of diversification corresponding to aridification of desert habitats as well as the geological events that gave rise to basin and range topography. We also apply an ancestral state reconstruction of traits hypothesized to be adaptations to arid climates and reconstruct historical biogeography using a modified version of the Dispersal-Extinction-Cladogenesis (DEC) model that accounts for heterogeneity in diversification rates. We interpret these results in light of classic hypotheses about the assembly of the southwestern desert flora and plant evolution in an insular biogeographic context.


1 -
2 - University Of California, Jepson Herbarium & Dept. Of Integrative Biology, 1001 Valley Life Sciences Bldg. #2465, Berkeley, CA, 94720, United States

Keywords:
aridification
Asteraceae
biogeography
dispersal
Edaphic evolution
Compositae
deserts
islands
paleoclimate
Perityleae
phylogenomics
rock daisies
Sky islands.

Presentation Type: Oral Paper
Number:
Abstract ID:964
Candidate for Awards:George R. Cooley Award


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