Graduation Date

Spring 2024

Document Type



Master of Science degree with a major in Biology

Committee Chair Name

John Reiss

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Karen Kiemnec-Tyburczy

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Sharyn Marks

Third Committee Member Affiliation

HSU Faculty or Staff

Fourth Committee Member Name

Allison Bronson

Fourth Committee Member Affiliation

HSU Faculty or Staff


Olfaction, Morphology, Plethodontid, Electron microscopy, MicroCT scanning, Histology

Subject Categories



Many amphibian species rely on olfaction for locating prey and for social interactions during different life stages. Despite the importance of the olfactory system, research on its structure has been taxonomically limited. The most diverse family of salamanders, the Plethodontidae, has been largely excluded from research efforts to describe olfactory morphology. Although several histological studies have been conducted, no studies have yet looked at morphology at the level of ultrastructure using electron microscopy. The primary goal of my research was to examine olfactory morphology and ultrastructure in plethodontid species with a range of life history strategies, to better understand the relationship between habitat, life history, and morphology. Utilizing standard histology, transmission electron microscopy, and MicroCT scanning, I examined four species within Plethodontidae, Batrachoseps attenuatus, Gyrinophilus porphyriticus, “Eurycea bislineata” (a species complex), and Eurycea troglodytes, and one outgroup species, Rhyacotriton variegatus.

In the direct-developing and biphasic plethodontids I examined, the main olfactory cavity (MOC) of the adult is a sac-like structure with the vomeronasal organ (VNO) as a lateral diverticulum. The MOC in aquatic stages (larvae and paedomorphic adults) is tubular, extending from the external naris to the choana, with a very small VNO. The ultrastructure in the VNO across all species and stages indicates a stronger correlation between phylogeny and cell type than life history and cell type. In the MOC, I found no apparent correlation between cell types and life stage. I conclude that the cellular composition of the plethodontid MOC may be shaped by both phylogeny and habitat.

Citation Style




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