title: A new cytotype of Simulium squamosum from south-west Cameroon.
abstract: A new cytotype of Simulium squamosum Enderlein (Diptera: Simuliidae) (here named S. squamosum'D') is described from around Mount Cameroon in south-west Cameroon on the basis of sex-chromosome differences on the short arm of chromosome I. Two polymorphic inversions, IS-To (a new inversion) and IS-2, are partially Y linked. These inversions usually occur together, although IS-To has a higher frequency and is more strongly Y linked than IS-2. This sex-chromosome system has not been previously described and the occurrence and evolution of sex-chromosome systems in S. squamosum is discussed.
authors.affiliation: Department of Entomology, The Natural History Museum, London, UK.
authors.forename: M
authors.initials: M
authors.lastname: Mustapha
authors.forename: R J
authors.initials: RJ
authors.lastname: Post
authors.forename: P
authors.initials: P
authors.lastname: Enyong
authors.forename: J
authors.initials: J
authors.lastname: Lines
mesh_terms: D000818:Animals; D002163:Cameroon; D007446:Chromosome Inversion; D003582:Cytogenetics; D005260:Female; D008297:Male; D012730:Sex Chromosomes / Q000235:genetics*; D012843:Simuliidae / Q000145:classification / Q000166:cytology / Q000235:genetics* / Q000648:ultrastructure