Cephalodella parasitica (Jennings, 1894)
Most likely ID: n.a.
Sampling location: Simmelried
Phylogenetic tree: Cephalodella parasitica
- body slender, distinctly curved
- length 120–200 µm (with toes)
- head tapers toward corona
- corona oblique, without lips
- mastaxs large, trophi of normal type
- well marked neck fold
- cuticle transparent, flexible, without lateral cleft
- gastric glands often brownish or black colored
- no eyespot and no retrocerebral organ
- ectoparasitic lifestyle on oligochaetes like Stylaria or Nais
- toes one sixth of body length, sometimes slightly S-shaped
- foot short, conically shaped
So far I have found Cephalodella parasitica only twice, in a few specimens. The first find was in October 2002 and the second 6 years later in October 2008 (s. fig. 4). Both finds were in samples from the Simmelried. Before and after that I have no further records.
The identification of Cephalodella parasitica is clear, as it is the only Cephalodella species with an ectoparasitic lifestyle on the cuticle of oligochaetes. I found Cephalodella parasitica on Stylaria in 2002 (s. figs. 1 a-b, 2 a-c and 3) and on Nais in 2008 (s. fig. 4). Chaetogaster and Vejdovkyella are mentioned as further hosts. The specimens hold on tightly with their pointed tweezer-like unci and will not be detached even by vigorous movements of the host. I could observe that the cuticle of the host is plucked with the uni. I could not determine whether the cells of the cuticle are actually feeded or only the bacteria growing on them. With increasing pressure of the coverslip, the specimens detached and start to swim around freely (s. fig. 5 a-b). Cephalodella parasitica lays its eggs on the host.
Fig. 1 a-b: Cephalodella parasitica. The oligochaete Stylaria infested by several specimens (arrows), which has bitten into the cuticle of Stylaria. Obj. 10 X.
Fig. 2 a-c: Cephalodella parasitica. L = 126 µm (with toes). A specimen is feeding on the cuticle of the oligochaete Stylaria. Obj. 40 X.
Fig. 3: Cephalodella parasitica. L = 115 µm (with toes). A second specimen feeding on the cuticle of the oligochaete Stylaria. Obj. 40 X.
Fig. 4: Cephalodella parasitica. L = 188 µm (with toes). A specimen found in Oct 2008, which is bitten into the head of the oligochaete Nais. Obj. 60 X.
Fig. 5 a-b: Cephalodella parasitica. L = 138 µm (with toes). A freely swimming specimen. Obj. 40 X.