TANGLED WEBS AND SPIDER-FLOWERS: PHYLOGENOMICS AND THE EVOLUTIONARY HISTORY OF CLEOMACEAE

Theresa Conley Saunders

doi:10.7273/000007462

The spider-flower family Cleomaceae consists of ~27 genera and ~270 species distributed across all continents except Antarctica, with most taxa found primarily in warm temperate, tropical, or desert regions. While the family has potential to be important in various studies of evolutionary biology, research is hindered by the lack of a robust family phylogeny and resolved generic boundaries. Efforts to broadly sample across the family are complicated by the world-wide distribution. In this dissertation, we use primarily herbarium vouchers and high- throughput DNA sequencing in combination with the Angiosperms353 probe set to evaluate patterns of phylogenetic, biogeographic, and morphological diversity in Cleomaceae. In chapter 1, we produce a robust phylogenetic tree with sampling representing ~86% of the diversity in Cleomaceae to (1) resolve generic relationships in Cleomaceae and compare to previous hypotheses of relationships and diversification patterns, (2) examine patterns of historical biogeography, (3) assess phylogenetic signal in seed morphology, and (4) explore the placement of seed fossils in this phylogenetic context. Our results confidently resolve generic boundaries within Cleomaceae and identify the genus Cleomella as sister to the rest of the family. An ancestral range of Africa and the Palearctic is proposed, as well as a divergence from sistering family Brassicaceae ~56 mya. High resolution images of seeds from ~80% of the diversity in Cleomaceae are evaluated and compared to the fossil record to reveal considerable variation across the family that mostly mirrors generic relationships. In chapter 2, we then further examine the phylogenetic relationships of the genus Andinocleome, one of the South American genera in Cleomaceae, that has unresolved species boundaries due to complicated morphology, suspected hybridization between species, and a lack of genetic data. We robustly sample DNA tissue from across the genus to (1) examine species boundaries in Andinocleome based on high-throughput sequencing of herbarium vouchers (2) study the impact, or lack thereof, of hybridization in Andinocleome, and (3) identify genetic variation among morphological clusters within one particularly variable species, A. anomala. Despite past difficulty in resolving species relationships in Andinocleome, our results present a genus with well-resolved species and genetic structuring within A. anomala. We use multiple lines of genetic evidence to identify instances of hybridization in the genus, particularly involving the species A. anomala, A. glandulosa, A. moritziana, and A. lechleri. Finally, in chapter 3, we continue our work in Andinocleome and examine the morphological diversity across all species of the genus by (1) collecting and analyzing qualitative and quantitative morphometric characters from herbarium vouchers, (2) comparing the morphological variation to the previous genetic work done in manuscript 2, and (3) evaluating the morphology and species boundaries of the group in the context of their geographic distribution. Statistical analyses of morphometric data in Andinocleome reveal a continued story of complicated and overlapping morphological variation between species, with much of the variation in the genus not aligning with current species circumscriptions. Despite this difficulty, species and some hybrid individuals can be identified based on a combination of characters. We also find that the geographic distributions of species in the genus across the Northern and Central Andes explains some of the morphological variation and can help identify hybridization between species.

TANGLED WEBS AND SPIDER-FLOWERS: PHYLOGENOMICS AND THE EVOLUTIONARY HISTORY OF CLEOMACEAE

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