Planetary Biodiversity Inventory

This document is organized into 22 peer-reviewed chapters. Each of the chapters focuses on an individual cestode group, begins with the status of knowledge of the group prior to the inception of the PBI project, and ends with an assessment of the current understanding of the group. In each case, diversity, classification, morphology, phylogenetic relationships, host associations, and geographic distribution are addressed. In all but one case, each chapter includes a list of valid taxa. Synonyms have not generally been listed; this was determined to be beyond the scope of the project given the immensity of such lists for some groups. With over 3,000 valid species, the generation of a list of species for the Cyclophyllidea was also determined to be beyond the scope of this project. However, a list of valid higher taxa is provided. Each of the 19 cestode orders is addressed alphabetically in separate chapters with two exceptions. The Mesocestoididae are treated as a family in the Cyclophyllidea. Although evidence supporting recognition of the former as an independent order is mounting, the case remains to be formally made based on more detailed investigations of this enigmatic group of mammal parasites. The Onchoproteocephalidea are the second exception. So as to emphasize the dual nature of the host associations and scolex morphology of its members, the freshwater fish-parasitizing taxa (formerly assigned to the order Proteocephalidea) are treated in a chapter as the Onchoproteocephalidea I separately from the taxa that parasitize elasmobranchs, which are treated as the Onchoproteocephalidea II. Use of quotation marks around taxon names (e.g., the order "Tetraphyllidea") is to remind readers of the definitively non-monophyletic nature of these groups.