Publication Date

Spring 2016

Advisor(s) - Committee Chair

Keith Philips (Director), Scott Grubbs, Lawrence Alice

Degree Program

Department of Biology

Degree Type

Master of Science


The Psephenidae is a family of freshwater beetles usually found in swift streams worldwide. Their unique disc shaped and flattened larvae have made this a group of interest for scientists for centuries. Morphologically, this family has been relatively well researched, and systematically the family is fairly well known and supported as monophyletic. One issue with Psephenidae, and with many other insect groups, is the lack of the molecular phylogenetic analyses to test morphology hypothesizes.

After successfully sequencing these two genes from species representing nearly all of the known genera, the data were analyzed using both Bayesian and parsimony methods. Analyses were performed individually for each gene, a combined molecular analysis, using just morphological data, and a total evidence analysis using both molecular and morphological data. After analyzing the trees, definite inconsistencies were discovered between the current data set and the previous studies performed using only morphological characters. Individual gene analysis showed low support for the monophyly of proposed subfamilies within the psephenids, but combined molecular and total evidence analysis showed much more resolution as well as support for most but not all of the proposed subfamilies.

For this study, the relationships among the genera of this family were studied with both molecular and morphological data as well as combined in a total evidence analysis. DNA from specimens was extracted, amplified, and sequenced for all available genera that could be acquired locally and abroad through collaborators and their contacts in other countries. The nuclear gene Wingless (Wg) and the mitochondrial gene Cytochrome Oxidase 1 (CO1) were utilized in this study; amplification of several other nuclear genes was attempted but the results were poor and they were excluded from the analysis.


Animal Sciences | Biology | Ecology and Evolutionary Biology | Zoology