Date of Award


Document Type


Degree Name

Master of Science (MS)


Biological Sciences

First Advisor

Kenneth G. Karol, Ph.D.

Second Advisor

Joseph W. Rachlin, Ph.D.

Third Advisor

Richard M. McCourt, Ph.D.


The Klebsormidiophyceae are a class of green microalgae found globally in both freshwater and terrestrial habitats. Morphology-based classification schemes of this class have been shown to be insufficient, particularly due to the simple morphology of these algae, the tendency of morphology to vary in culture versus in field conditions, and rampant morphological homoplasy. Molecular studies revealing cryptic diversity have renewed interest in this group. We sequenced the complete chloroplast genomes of taxa in the Klebsormidiophyceae representing the known taxonomic breadth of this class, as well as the chloroplast genomes of three strains of Streptofilum, a recently discovered algal lineage that may constitute a new class within the Charophyta. Our results affirm the polyphyly of Klebsormidium, as well as the polyphyly of the nominal species in this genus, Klebsormidium flaccidum. Furthermore, we provide evidence that Streptofilum constitutes a new lineage of algae that is sister to the Klebsormidiophyceae plus Phragmoplastophyta. We also uncovered major structural alterations in the chloroplast genomes of species in Klebsormidium that could have broader implications regarding underlying mechanisms of chloroplast genome evolution.

Available for download on Thursday, September 14, 2023