Defense Date


Document Type


Degree Type

Master of Science

Degree Name

Marine Science

First Advisor

Timothy Swain Ph.D.

Second Advisor

Abigail Renegar Ph.D.

Third Advisor

Jose Lopez Ph.D.


The study of systematics has been around for over 200 years. Some recent systematic studies have shifted to the idea of genetic barcoding for identification and classification. This shift is notably present in the cnidarian order Zoanthidea. Systematists have employed genetic barcoding exclusively for the classification of these animals resulting in taxonomic uncertainty. A prominent Mediterranean species complex (Parazoanthus axinellae) is at the center of these taxonomic issues. Recently two color-morpho-types: “slender” yellow and “stocky” orange have been used to differentiate modern P. axinellae specimens, advancing the uncertainty associated with this complex. This lack of taxonomic identity becomes a prevalent issue now that P. axinellae is increasing in modern ecological publications. Using integrative systematics, the complete historical and modern boundary of the P. axinellae species complex was investigated. Based on a multi-gene phylogeny there are three subclades in the P. axinellae species complex designated here as: P. axinellae (restricted), P. aff. juan-fernandezii (Mediteranean-1), and P. aff. juan-fernandezii (Mediteranean-2). These clades appear to follow the idea of the color-morpho-types to some degree, where the “slender” yellow can be used to distinguish P. axinellae (restricted) from the “stocky” orange P. aff. juan-fernandezii (Mediterranean-1) and (Mediteranean-2). Microanatomical differences in column mesoglea as well as microneme length and thickness were detected between P. axinellae (restricted) and P. aff. juan-fernandezii (Mediterranean-1). Unfortunately, due to the historical ambiguity, we were unable to match these clades to any historical boundaries. The P. axinellae (restricted) distribution can be expanded to include the East Coast of the United States.