Defense Date

12-8-2023

Document Type

Thesis

Degree Type

Master of Science

Degree Name

Marine Science

First Advisor

Timothy D. Swain, Ph.D.

Second Advisor

Bernhard Riegl, Ph.D.

Third Advisor

Jose V. Lopez, Ph.D.

Keywords

Nematocysts, Cnidome, Taxonomy, Evolution, Phylogenetics, Cnidaria, Anthozoa, Zoantharia, Kleptocnidism

Abstract

For over a century, taxonomists have debated the systematic value of cnidae in Anthozoa. Though most species descriptions of Zoanthidea (Cnidaria: Anthozoa) include data on cnidae assemblages, phylogenetic analysis of the cnidome across Zoanthidea has not been attempted. The integrative systematics approach used here aims to connect taxa identified by nucleotide sequence with the existing morphology-based taxonomic system by reinterpreting classical phenotypic characters, such as cnidae size and distribution, in the light of modern molecular data. Characters representing the sizes of four cnidae types (holotrichs, b-mastigophores, p-mastigophores, and spirocysts) and their distributions among tissue compartments (tentacles, actinopharynx, mesenterial filaments, and body wall) were mapped to the molecular phylogeny of Zoanthidea. Multiple characters, such as spirocyst surface area and b-mastigophore abundance in the actinopharynx, showed moderate phylogenetic signal and may be useful for integrative taxonomy. The analysis also demonstrated that each tissue compartment is characterized by a specific type of cnida. This novel finding sheds light on the functional roles of each cnida type, which to date have not been fully elucidated across Cnidaria. Investigation of cnidome data in modern and historical species descriptions further revealed that kleptocnidism may be common in Zoanthidea, the first cnidarians to demonstrate this remarkable trait.

ORCID ID

0000-0002-9081-6366

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Available for download on Saturday, January 06, 2029

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