Abstract

The Megalagrion damselflies of Hawaiʻi present a valuable study system for understanding the impacts of geology on evolutionary processes. Despite their significance, our understanding of the temporal, geographic, and phylogenetic origins of these damselflies remains incomplete. Prior phylogenetic studies have proposed adaptive ecological and morphological progressions, but evaluating these hypotheses relies on a sound understanding of phylogenetic relationships within the genus. Previous phylogenetic analyses have produced conflicting topologies. To resolve these uncertainties, we performed phylogenetic analyses including divergence time estimation with 90 nuclear loci (>50 kbp) and 2 mitochondrial loci (>1000 bp), sampling representatives from each genus within core Coenagrionidae and 90% of Megalagrion species, including multiple island populations. Our methods included ancestral range estimation, paleodiversity analyses, agent-based simulation modeling, and ancestral state reconstruction to test biogeographic and diversification hypotheses. Our findings indicate that the ancestor of Megalagrion diverged from core Coenagrionidae in the early Eocene (~ 50 MA) with extinction likely playing a significant role in the early evolution of Megalagrion. The most recent common ancestor of Megalagrion predates the emergence of Kauaʻi by 7-15 MY. The extant diversity of Megalagrion is largely explained by ecological diversification into at least five distinct clades that likely occurred on now-sunken Northwestern Hawaiian Islands, then dispersal to the current Hawaiian Islands as they emerged.

Degree

MS

College and Department

Life Sciences; Biology

Rights

https://lib.byu.edu/about/copyright/

Date Submitted

2024-08-19

Document Type

Thesis

Keywords

phylogenetics, odonata, agent-based modeling, evolution

Language

english

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