Aspects of the life history and origins ofNesolecithus africanus(cestoda: Amphilinidea)

Abstract
Larvae of the amphilinidean platyhelminth Nesolecithus africanus are reported and described from the freshwater prawn Desmocaris trispinosa in Nigeria. The worms were found in the haemocoel of female prawns and appear to restrict ovarian development. Taxonomic, zoogeographical and evolutionary relationships of the species with its South American relative, N. janickii, are discussed. These species are very similar morphologically, and restricted to parts of the African and South American continents which were adjacent in Cretaceous times. They are probably vicariant Gondwanaland relicts, little changed over the past 100 million years. Two theories of amphilinidean origin are discussed.