Dissertation
PHYLOGENETIC, PHYLOGEOGRAPHIC, AND MORPHOLOGICAL STUDIES OF DIVERSIFICATION IN EUCNIDE (LOASACEAE)
Washington State University
Doctor of Philosophy (PhD), Washington State University
01/2021
DOI:
https://doi.org/10.7273/000003154
Handle:
https://hdl.handle.net/2376/120954
Abstract
Eucnide (Loasaceae) consists of about 15 species distributed across Mexico, Guatemala, and the North American Southwest, a geographically complex landscape made up of floristically unique deserts, large mountain ranges, and a large, geographically isolated peninsula. This complex geography is credited for high levels of biodiversity and endemism in the region. We examine patterns of phylogenetic, phylogeographic, and morphological diversity in Eucnide. To date, no molecular phylogenetic studies have broadly sampled species in this genus. We use phylogenetic analyses to: 1) test the monophyly of Eucnide sections and assess whether the existing taxonomy sufficiently circumscribes diversity within the genus; 2) assess the divergence times of Eucnide lineages to determine when the major clades diversified; and 3) estimate the ancestral range of Eucnide and hypothesize patterns of geographical diversification of the genus. We then further examine the phylogeographic diversity of the Eucnide distributed on the Baja Peninsula, specifically of E. cordata and section Sympetaleia (E. aurea, E. tenella and E. aurea). Three major vicariance events to have been inferred to have played a role is shaping the distribution of many organisms of the Baja Peninsula. These proposed vicariance events—the formation of the Sea of Cortez, an Isthmus of La Paz seaway, and a putative mid-peninsular seaway—have had a demonstrated impact the distributions and genetic diversity numerous organisms. E. cordata and section Sympetaleia show contrasting phylogeographic patterns. Eucnide cordata appears to have migrated on to the peninsula relatively recently while section Sympetaleia originated on the peninsula and shows string support for the mid-peninsular seaway hypothesis. Finally, we examine the morphological diversity of E. hirta, a species distributed mostly in the South of Mexico. There have been several taxonomic treatments of Eucnide with E. hirta being subject to several names resulting in substantial confusion as to the correct names for this species. The morphological variation of floral traits in the E. hirta complex did not identify potential patterns of morphological variation that might correspond to previously identified phylogenetic and geographic structure.
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Details
- Title
- PHYLOGENETIC, PHYLOGEOGRAPHIC, AND MORPHOLOGICAL STUDIES OF DIVERSIFICATION IN EUCNIDE (LOASACEAE)
- Creators
- Joshua Brindley
- Contributors
- Eric H Roalson (Advisor)Larry Hufford (Committee Member)Omar E Cornejo (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Sciences, School of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 89
- Identifiers
- 99900652003901842
- Language
- English
- Resource Type
- Dissertation