HCNSO Student Theses and Dissertations

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Defense Date


Document Type

Thesis - NSU Access Only


Oceanographic Center

First Advisor

Charles G. Messing

Second Advisor

Michael R. J. Forstner

Third Advisor

Mahmood Shivji


The crinoid family Comasteridae has undergone several revisions based on morphological characters. None, however, have employed DNA sequence data to generate a phylogenetic hypothesis for the group. To elucidate both monophyletic clades and generic interrelationships, DNA was obtained from 32 taxa, and 655 aligned base positions from near the 3' terminus of the mitochondrial 16S rDNA gene were sequenced. The results of analyses by maximum parsimony, neighbor-joining, and maximum likelihood methods support the majority of the current morphologically defined generic designations, though one genus emerges as paraphyletic and another as polyphyletic. Intergeneric relationships are less clear though strong support of several sister-clade relationships is evident including Comatella/Alloeocomatelia and Comanthus (in part)/Clarkcomanthus. Subfamilial designations are moderately to strongly supported in the Comanthinae but weakly supported elsewhere.

This initial assessment of phylogenetic relationships within the family poses a number of additional questions and directions for future research. It will serve as the launching point for future systematic research both within the family Comasteridae and for comatulid crinoids in general.

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