Graduation Year

2023

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Biology (Integrative Biology)

Major Professor

Stephen M. Deban, Ph.D.

Committee Member

Robert Dudley, Ph.D.

Committee Member

Ryan M. Carney, Ph.D.

Committee Member

Bradford J. Gemmell, Ph.D.

Keywords

aerial, behavior, biomechanics, morphology, parachute, plethodontid

Abstract

The jumping and subsequent aerial behaviors of arboreal lungless salamanders (genus Aneides) had never been investigated or described. The aims of this research were to (1) compare jumping performance within the family Plethodontidae with a special focus on arboreal species from genus Aneides, (2) describe the biomechanics and kinematics of aerial behaviors after a jump or extended fall, and (3) model airflow over the morphology of the most aerially adept salamanders to investigate if they are capable of generating lift. First, I recorded salamanders jumping, locomoting vertically, dropping, and flying in a vertical wind tunnel. Then, I laser-scanned and reconstructed salamanders to compare morphological contributions to aerodynamics with computational fluid dynamics (CFD). Arboreal salamanders (genus Aneides) jump slower but assume skydiving postures more quickly. In Aneides, aerial performance follows an arboreality gradient with the more arboreal A. vagrans and A. lugubris capable of aerial righting, parachuting, and gliding; the less arboreal A. flavipunctatus and E. eschscholtzii rarely parachute, never glide, and display erratic aerial behaviors, such as flailing. CFD simulations predict a stronger dorso-ventral pressure gradient and a positive lift (Cl) and drag (Cd) coefficient for A. vagrans, suggesting a higher capacity for lift. The highly arboreal A. vagrans has a positive predicted Cl:Cd ratio of 0.40 that increases with angle of attack up to 10º. The long limbs and active tail of arboreal salamanders, often cited as adaptations for climbing, may also contribute to parachuting and gliding when falling from trees.

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