Graduation Date
Spring 2023
Document Type
Thesis
Program
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
Sharyn Marks
Second Committee Member Affiliation
HSU Faculty or Staff
Third Committee Member Name
Karen Kiemnec-Tyburczy
Third Committee Member Affiliation
HSU Faculty or Staff
Fourth Committee Member Name
Allison Bronson
Fourth Committee Member Affiliation
HSU Faculty or Staff
Subject Categories
Biology
Abstract
The olfactory system of living amphibians (Lissamphibia) undergoes major changes as it transitions from an aquatic to a terrestrial system during metamorphosis. Patterns of change in the cellular morphology of the nose have been examined for frogs (Anura) and salamanders (Caudata). However, it remains unknown if caecilians (Gymnophiona) have similar patterns of change in their nasal ultrastructure. In particular, no data on larval caecilian olfactory cell types are available. Here, using light microscopy and transmission electron microscopy, I examined the olfactory organ of larvae of the caecilian Ichthyophis kohtaoensis, to establish the ultrastructure of the epithelium and compare it to that of other amphibians. I found that there are microvillar receptor cells, ciliated receptor cells, and secretory supporting cells in the main olfactory epithelium (MOE) of I. kohtaoensis. However, in the posterior portion of the main olfactory cavity (MOC), the cells appear disorderly and “loose” with a haphazard orientation, in comparison to the anterior portion of the cavity where cells are neatly arranged and closely packed. There are only ciliated receptor cells and secretory supporting cells in the posterior MOC. The vomeronasal organ (VNO) of I. kohtaoensis has microvillar receptor cells, secretory supporting cells, ciliated supporting cells, and supporting cells with both cilia and microvilli. Interestingly, similar cell types and a disorderly appearance of the posterior main olfactory epithelium have also been described in adult Typhlonectes compressicauda, the only other caecilian for which ultrastructural data exist. Apart from I. kohtaoensis not having any ciliated supporting cells in the main olfactory cavity, the epithelium of both the MOC and the VNO resembles that of other amphibian larvae.
Citation Style
Journal of Morphology
Recommended Citation
Patmore, Jaclyn M., "Olfactory organ morphology and ultrastructure of the larval Koh Tao Island caecilian (Ichthyophis kohtaoensis)" (2023). Cal Poly Humboldt theses and projects. 661.
https://digitalcommons.humboldt.edu/etd/661