Date Awarded


Document Type


Degree Name

Doctor of Philosophy (Ph.D.)


Virginia Institute of Marine Science


Eric J. Hilton


The ribbonfish family Trachipteridae (Lampridiformes) includes three well-defined genera (Trachipterus, Desmodema, and Zu), which are distributed worldwide throughout the pelagic marine environment as with most families of Lampridiformes, drastic changes in morphology occur throughout ontogeny due to extreme allometric growth. Combined with the rarity of specimens, this has led to the description of different life history stages as different species, rather than as part of the ontogenetic continuum of a single species. There is significant uncertainty concerning the ontogeny, distribution, nomenclature, number and phylogenetic affinity of trachipterid and other lampridiform genera.;The first chapter of my dissertation is a taxonomic review of of the family Trachipteridae. This chapter provides updated genus (Trachipterus, Desmodema, and Zu) and species descriptions ( Desmodema and Zu) and a synthesis of life history, biogeographic, and ontogenetic data for trachipterid fishes, including examination of an abundance of material from the western Pacific Ocean. Additionally, numerous new morphological observations are described and an updated key to the trachipterid genera, applicable to both juvenile and adult stages, is provided.;The phylogenetic systematics of all lampridiform genera (Metavelifer, Velifer, Lampris, Lophotus, Eumecichthys, Radiicephalus, Agrostichthys, Regalecus, Trachipterus, Desmodema, Zu) is examined in the second chapter of my dissertation. I used 62 morphological characters from across the ontogenetic continuum to test proposed hypotheses of genus-level relationships of Trachipteridae and familial monophyly of the Lampridiformes. All lampridiform families were recovered as monophyletic except for the Lophotidae, resulting in Eumecichthys as incertae sedis. The suborder Taeniosomoidei is proposed to reflect the monophyletic clade consisting on long-bodied lampridiforms. Trachipteridae is recovered as monophyletic sister group to Regalecidae. The superfamily Trachipteroidea is proposed to recognize this clade. However, within the Trachipteridae, a monophyletic clade consisting of Trachipterus + Zu is recovered but with low support.



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