Dissertation/Thesis Abstract

Handedness Is Not Linked to Locomotion in a Basal Anuran
by Sullivan, Rachel A., M.S., Southern Illinois University at Edwardsville, 2018, 34; 10808549
Abstract (Summary)

Frogs exhibit a range of locomotor behaviors, which can be broadly grouped based upon limb movement patterns. Asynchronous behaviors are those that involve alternating limb movements and include crawling, climbing, burrowing, and asynchronous (trot) swimming. Synchronous behaviors are those that involve simultaneous limb movements and include jumping, lunge feeding, and synchronous (frog-kick) swimming. The degree of handedness (preferential limb use) in motor responses is thought to reflect functional lateralization of the brain, an indicator of neural complexity. Handedness has been examined across a range of anuran taxa and has been hypothesized to be related to a species’ preferred locomotor mode, with greater handedness predicted in species that make more extensive use of asynchronous locomotion. In contrast, it has been hypothesized that anuran handedness varies phylogenetically, with ambidexterity being the ancestral condition and handedness being derived. To date, research in this area has focused primarily on derived taxa and relatively little is known about basal taxa. The basal-most anuran family Leiopelmatidae is the sister group to all other frogs (Lalagobatrachia), and represents an excellent test of these competing hypotheses. Moreover, leiopelmatids rely exclusively on asynchronous swimming and likely exceed all other anuran taxa in their reliance on alternating limb movements during locomotion. We tested these competing hypotheses by examining handedness in two behaviors, righting response and trot-swimming, in the leiopelmatid Rocky Mountain Tailed Frog, Ascaphus montanus. Tailed Frogs showed no evidence of handedness despite the prevalence of asynchronous locomotion in their behavioral repertoire. The absence of handedness in a highly asynchronous basal anuran taxon, suggests that this phenomenon was not characteristic of the earliest frogs, but rather appeared later in the evolutionary history of the group.

Indexing (document details)
Advisor: Essner, Richard L.
Commitee: Jennings, David H., Lee, Danielle N.
School: Southern Illinois University at Edwardsville
Department: Biological Sciences
School Location: United States -- Illinois
Source: MAI 57/06M(E), Masters Abstracts International
Subjects: Zoology
Keywords: Anurans, Ascaphus, Behavior, Handedness, Locomotion, Phylogenetic
Publication Number: 10808549
ISBN: 978-0-438-01510-4
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