Redescription of Bolbosoma capitatum (Acanthocephala: Polymorphidae) from false killer whale off Vancouver Island, with taxonomic reconsideration of the species and synonymy of B. physeteris

Many individuals of the acanthocephalan Bolbosoma capitatum yon Linstow (1880) Porta, 1908 were collected from a stranded false killer whale, Pseudorca crassidens (Owen, 1846), off Vancouver Island, British Columbia, Canada, in 1989. This material provided the source of the first comprehensive description of the species, whose identity has been in dispute for over 100 yr. Many specimens collected from whales in 18 locations in the Mediterranean and off Faeroe Islands, North and South America, Caribbean, Africa, Great Britain, Japan, and Australia were examined and determined to belong to B. capitatum. Specimens of Bolbosoma physeteris Gubanov, 1952 collected from the same type host and locality listed in the original description were also determined to be B. capitatum, making B. physeteris a junior synonym. The most important determining characters are proboscis armature and variations in the spination of the area between the anterior and posterior cephalic bulbs.