Prorodon aklitolophon n.spec.and the “Dorsal Brush” as a Character to Identify Certain Subgroups in the Genus Prorodon

Abstract

Summary A description is given of the life cycle and the infraciliature of a new histophagous member of the genus Prorodon, P.aklitolophon.Its infraciliature was studied by means of the dry silver technique of Klein , the Chatton and Lwoff silver impregnation and the pyridinated silver-carbonate-method of Fernandez-Galiano .It was found that these three methods lead to clearly different results which could only be interpreted correctly with the help of comparative scanning and transmission electron microscopy. In most places the somatic cortex has monokinetids with either one or two parasomal sacs, only the most anterior kinetids grouped around the oral opening consist of ciliated dikinetids.The so-called “dorsal brush” consists of dikinetids, here only the anterior kinetosomes bear a non-clavate cilium which is shorter and slightly thinner than the somatic cilia. The biometric data of P.aklitolophon are given and the new species is compared with other hitherto described Prorodon species.Being aware of the rather unsatisfactory situation of the taxonomy in the genus Prorodon an attempt of a new classification is made showing how the structural organization of the dorsal brush might be used to establish 4 subgroups in a future revision of the genus Prorodon.