Liesl L. van As

Mantoscyphidians occur in high numbers on the gills of South African Haliotis and limpet species. This provided the ideal opportunity to study asexual and sexual reproduction, for the first time in different African Mantoscyphidia Jankowski, 1985 populations. Descriptions of the reproductive processes found in scyphidiid peritrichs were until now, mostly based on line drawings. Scanning electronand light microscopy contributed uniquely, in providing detail information regarding binary fission, telotroch formation and conjugation. Mantoscyphidia spadiceae Botes, Basson and Van As, 2001 shed the most light on binary fission. Micronuclear division occurred first with the plane of fission already evident and macronuclear cleavage ended just before final separation took place. Fission is not complete until a small string of pellicle that joins the daughter cells finally separates. Information on telotroch development was gathered from M. branchi Van As, Basson and Van As, 1998 and M. spadiceae populations. Telotrochs were between 36.7 and 38.6% shorter than live, extended mantoscyphidians and their swimming action resembled mobiline peritrichs. Mantoscyphidia branchi populations also proved to be most useful for conjugation studies. Conjugation included three progamic nuclear divisions and preceded synkaryon formation and two metagamic nuclear divisions. The process required 24 hours to be completed.

Members of the Urceolariidae Dujardin, 1941 have been found associated with a wide variety of invertebrate hosts from freshwater and marine habitats. Five species have been described from molluscan hosts from Europe and America. This paper deals with an urceolariid (Leiotrocha Fabre-Domergue, 1888) collected from the gills of Cellana radiata capensis (Gmelin, 1791) and Scutellastra exusta (Reeve, 1854) from the east coast of South Africa, as well as Patella depressa Pennant, 1777 and Cymbula safiana (Lamarck, 1891) from the bulge (west coast) of Africa. A higher prevalence was found on C. radiata capensis (89%) and P. depressa (72%) compared to the other two hosts. The urceolariid collected from the African limpets was identified as L. patellae (Cuénot, 1891). This is the first record of an urceolariid from any African hosts, including representatives of the Mollusca. Five urceolariid species were identified and described from gastropods, i.e. L. patellae Cuénot, 1891,U. karyolobia Hirshfield, 1949, U. cellanae Suzuki, 1950, U. viridis Richards, 1971 and U. parakorschelti Irwin, Sabetrasekh and Lynn, 2017. Motivation is provided why U. cellanae and U. viridis should be reallocated to the genus Leiotrocha, and U. karyolobia not. The taxonomic validity of the recent description of U. parakorschelti from limpets is commented on.