Date Awarded


Document Type


Degree Name

Doctor of Philosophy (Ph.D.)


Virginia Institute of Marine Science


Eugene Burreson


The phylogeny of the Piscicolidae was analyzed from combined sequence data of 18S rDNA, cytochrome c oxidase subunit I (CO-I), nicotinamide adenine dinucleotide dehydrogenase subunit I (ND-I), and morphological data using parsimony. A worldwide distribution of Pisciolidae was represented for the first time in a phylogenetic analysis. While the family Piscicolidae was supported as a monophyletic group, the traditional subfamilies based on morphology were not supported. The Platybdellinae was polyphyletic and formed four distinct clades, and Bathybdella sawyeri did not group with any other platybdellids. The Piscicolinae was also polyphyletic, also forming four distinct clades. The pontobdellid genus Stibarobdella was shown to be the basal taxon within the Pisciolidae; however, the Pontobdellinae was found to be paraphyletic if Oxytonostoma was included. The genera Aestabdella, Austrobdella, and Malmiana were found to be paraphyletic; the genera Calliobdella, Cystobranchus, and Platybdella were found to be polyphyletic. The species Myzobdella lugubris was not found to be monophyletic. It is proposed that Oxytonostoma be removed from the Pontobdellinae, that Aestabdella be synonymized with Pterobdella, that Calliobdella vivida, Cystobranchus mammillatus, Cystobranchus meyeri, Cystobranchus salmositicus, and Cystobranchus virginicus be reassigned to Gonimosobdella, and that Piscicolaria be synonymized with Myzobdella. The synonymy of Malmiana and Heptacyclus is confirmed, with Heptacyclus having priority. Piscicola milneri is confirmed to be a separate species from Piscicola geometra. Eleven species of freshwater leeches from North America are redescribed. The description of Gonirnosobdella mammillata is emended to correctly describe the conducting tissue and atrium. The reassignment of Piscicola sahnositica to Cystobranchus and now Gonirnosobdella is confirmed on the basis of the conducting tissue arrangement and absence of mycetomes. The description of Gonirnosobdella virginica is emended to include information on pigmentation, conducting tissue, accessory gland cells, coelomic system, and mycetomes. The reproductive and coelomic systems of Gonimosobdella meyeri, Myzobdella reducta, Piscicola milneri, and Piscicola punctata are reported for the first time.



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