title: Redescription and new data on Microsomacanthus diorchis (Fuhrmann, 1913) (Cestoda: Hymenolepididae).
abstract: Microsomacanthus diorchis (Fuhrmann, 1913) is redescribed and illustrated on the basis of the type-material and new findings from common eider Somateria mollissima captured in Iceland and specimens from the same host species from the Barents, White and Bering Seas. A lectotype is designated and an amended diagnosis is provided. The main differentiating features of M. diorchis are the size and shape of rostellar hooks and the cirrus, the well-marked delay in the antiporal testis development and the bow-shaped uterus. This parasite is shown to be specific to S. mollissima for both Atlantic and Pacific populations of the host. Hymenolepis (Microsomacanthus) somateriae of Bishop & Threlfall (1974) [nec M. somateriae Ryzhikov, 1965] is recognised as a synonym of M. diorchis (Fuhrmann, 1913). The taxonomic position of the species described as Aploparaksis murmanica Baylis, 1919 from common eider is discussed.
authors.affiliation: Zoological Institute, Russian Academy of Sciences, 1 Universitetskaja Embankment, St. Petersburg, Russia.
authors.forename: Alexander K
authors.initials: AK
authors.lastname: Galkin
authors.forename: Jean
authors.initials: J
authors.lastname: Mariaux
authors.forename: Kira V
authors.initials: KV
authors.lastname: Regel
authors.forename: Karl
authors.initials: K
authors.lastname: Skirnisson
mesh_terms: D000818:Animals; D002589:Cestoda / Q000033:anatomy & histology*; D004372:Ducks / Q000469:parasitology; D005260:Female; D008297:Male