Multiscale glass lizard conservation genomics

O'Hearn, Dylan James

Permalink

https://hdl.handle.net/2142/130159 Copy

Description

Title

Multiscale glass lizard conservation genomics

Author(s)

O'Hearn, Dylan James

Issue Date

2025-07-10

Director of Research (if dissertation) or Advisor (if thesis)

Sperry, Jinelle

Doctoral Committee Chair(s)

Ward, Michael

Committee Member(s)

• Davis, Mark
• Suarez, Andrew

Department of Study

Natural Res & Env Sci

Discipline

Natural Res & Env Sciences

Degree Granting Institution

University of Illinois Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Anguinae
• glass lizards
• phylogenetics
• conservation
• species delimitation
• phylogeography
• Ophisaurus
• Hyalosaurus

Abstract

The glass lizards (subfamily Anguinae, family Anguidae) are a clade of semi-fossorial legless lizards represented by 20 described species on four continents. Their capacity to adapt, migrate, and diversify has allowed them to survive multiple episodes of pervasive environmental change since their first appearance approximately 50 million years ago. However, they may require human intervention if they are to overcome the novel challenges they face in the present. In my first chapter, I established the importance of examining the Anguinae at multiple spatial, temporal, and phylogenetic scales to best inform conservation efforts. I also identified three key knowledge gaps, including 1) questions of subfamily-level phylogeny and the dating of key ancient diversification and intercontinental migration events, 2) uncertainties in the phylogeny and taxonomy of the North American glass lizard genus Ophisaurus, and 3) the unknown phylogeographic origins of threatened populations in a North American subspecies, the western slender glass lizard Ophisaurus attenuatus attenuatus. Using a genomic dataset built from 120 Anguinae samples, including field-collected samples and museum specimens, I then sought to address these knowledge gaps using methods appropriate for each question and scale. In my second chapter, I performed a phylogenomic analysis of all five Anguinae genera and inferred the existence of a monophyletic clade dating to the early Oligocene and consisting of African, east Asian, and North American glass lizards, differing from all previous molecular analyses but agreeing with longstanding paleontological opinion. In my third chapter, I generated a dated Ophisaurus species tree and further assessed the degree of evolutionary independence between species and subspecies, supporting full species status for all major lineages. In my fourth chapter, I performed demographic, phylogenetic, and population genetic analyses within O. a. attenuatus and determined that disjunct populations in Illinois, Indiana, and Wisconsin arrived there following glacial retreat at the end of the last glacial maximum and have likely been isolated since then. Finally, in my fifth chapter, I summarized my results, explained how the gaps identified in the first chapter were addressed, and suggested future Anguinae research topics. These findings address longstanding questions of glass lizard history and build a foundation for informed and effective glass lizard conservation efforts at multiple scales.

Graduation Semester

2025-08

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/130159

Copyright and License Information

Copyright 2025 Dylan J. O'Hearn

Owning Collections