| dc.description.abstract | Parasitic flatworms in the class Monogenoidea Bychowsky, 1937 (Platyhelminthes) are demonstrable pathogens to wild and cultured fishes. The objective of this thesis was to diagnose (taxonomy and systematics) monogenoid infections in fishes of North America. The monogenoids described in this thesis were collected from a diverse group of hosts and environments including: a wild, invasive carp (Cypriniformes) from a major American river; a cultured, exotic tilapia (Cichliformes); a wild, endemic flyingfish (Exocoetidae) from the western Atlantic Ocean; and wild and captive rays (Myliobatiformes) in the western Atlantic Ocean and on exhibit in closed recirculating systems at a public aquarium respectively.
Few current-day parasitologists publish work on monogenoids from North America. As a product of this, many fishes in North America (exotic, invasive, or endemic) remain undocumented as hosts or host new, previously undiscovered monogenoids. Considering this, we surveyed a diversity of North American fishes (exotic, invasive, and endemic) for their monogenoids, particularly those unreported to host monogenoids (or any other parasite) in North America.
This thesis details the taxonomic identity and phylogenetic position of the monogenoids collected in each chapter. The sections in each chapter that do not pertain to the above-mentioned criteria discuss the significance of such infections or new morphological observations.
Chapter 1 reports the discovery of the first parasite infecting invasive silver carp in North America, Dactylogyrus cf. skrjabini (Dactylogyridae). Silver carp are Siberian xenocyprids (Cypriniformes) that have become invasive in North America after silver carp escaped aquaculture facilities in the 1970’s. Despite the focus on this fish from a management perspective, no parasite has ever been reported from silver carp in North America. Although we are the first to discover a parasite from silver carp in North America, many other silver carp parasites likely remain to be reported there. Chapter 2 reports the discovery of the first monogenoid infecting Nile tilapia (Cichliformes) in the U.S.A., Gyrodactylus cichlidarum Paperna, 1968 (Gyrodactylidae). Although this report comes from an aquaculture facility in Alabama, exotic Nile tilapia are introduced (with the potential to become invasive) in warmer climates in the U.S.A., and the presence of this parasite poses a risk to “spill over” to and cause pathology to related, endemic fishes that are sympatric to wild, exotic Nile tilapia. Chapter 3 reports the discovery of the second monogenoid infecting Nile tilapia in the U.S.A., Cichlidogyrus sclerosus Paperna & Thurston, 1969 (Dactylogyridae) and reviews the invasive range of C. sclerosus. This report comes from the same aquaculture facility as in chapter 2, and C. sclerosus presents similar risks to the monogenoid treated in chapter 2. Chapter 4 reports the discovery of a new species in the genus Axine (Axinidae) infecting Atlantic flyingfish (Beloniformes: Exocoetidae) from the western Atlantic Ocean. This species is distantly related to the monogenoids described in chapters 1–3 and represents the first species of Axine collected from a flyingfish in the western Atlantic Ocean. Through our morphological studies to identify the specimens of the new species we discovered and corrected ~250 years of literature that misinterpreted the morphology of the terminal female genitalia in Axine. Chapter 5 redescribes Benedeniella posterocolpa (Hargis, 1955) Yamaguti, 1963 (Capsalidae) and compares specimens of B. posterocolpa using morphology and nucleotides from cownose ray (type host), Brazilian cownose ray (newly reported host), and from giant manta (a charismatic ray kept in an aquarium with the type host) (all Myliobatiformes). We dismantle the presumption that B. posterocolpa is specific to the cownose ray. We also observe that the CO1 gene is variable between conspecific specimens of B. posterocolpa from the same individual host and is therefore ill advised to use as a species level barcode.
The reports included herein cover a diverse selection of hosts and environments and highlight the overlooked diversity of monogenoids that infect frequently encountered, exotic, invasive, or charismatic hosts in North America. North America is relatively well surveyed for monogenoids compared to other parts of the world. Therefore, the chapters below not only emphasize the abundance of remaining studies involving monogenoids infecting North American fishes but for the rest of the world too. | en_US |
