Trematode parasites of snails from Edgbaston Pool: the life history of the strigeid Cotylurus brevis Dubois & Rausch, 1950

Abstract

1. The life cycle of Cotylurus brevis Dubois and Rausch, from the cercaria to the adult, has been investigated for the first time by using laboratory-bred primary, secondary and definitive hosts. The holometabolic metamorphosis with the formation of a tetracotyle stage in a second intermediate host has been described in detail.2. The cercaria of C. brevis obtained from Lymnaea stagnalis in Edgbaston Pool has been found to be identical with Cercaria helvetica XXXIV Dubois from Lake Neuchâtel. The total number of flame cells in the cercaria is twenty, as opposed to the fourteen in the cercaria of Cotylurus cornutus Rudolphi (= ‘Strigea tarda’ described by Mathias (1925), Harper (1929, 1931) and Wesenberg-Lund (1934)).3. In nature the second intermediate host of Cotylurus brevis is Lymnaea stagnalis. Under experimental conditions L. pereger and L. auricularia were also found to act as second intermediate hosts, but neither Planorbis corneus, P. carinatus nor various leeches could act as second intermediate hosts.4. The tetracotyle stage of Cotylurus brevis is morphologically indistinguishable from the corresponding stage of other species of Cotylurus.