Intersexuality in Boeckella triarticulata (Thomson, 1883) (Copepoda, Calanoida):: A trap for unwary taxonomists

Copepod systematists should be careful not to attribute taxonomic significance to teratological structures. Given that only a minute fraction of copepod populations is subjected to microscopic examination, and that several workers have encountered intersexual individuals, intersexuality is not an extremely rare phenomenon. The fifth legs of an intersexual Boeckella triarticulata, the second to be recorded in the literature, are figured and described in detail. The factor that induces intersexuality does not affect all four rami of the fifth pair of legs uniformly; one ramus may be fully male in character and another almost completely female. Karukinka fueguina Menu-Marque, 2003 is probably based on two intersexual individuals of Boeckella poppei (Mrazek, 1901).