67.3 Friday, Jan. 6 Buddenbrockia plumatellae: a novel solution to being a worm OKAMURA, Beth*; HUMPHRIES, Stuart; GRUHL, Alexander; Natural History Museum, London; University of Hull, UK; Natural History Museum, London email@example.com
The enigmatic Buddenbrockia plumatellae is a worm-like endoparasite of freshwater bryozoans. In 2002 it was demonstrated to belong to the Myxozoa. More recent evidence places the Myxozoa within the Cnidaria, thereby implying an adaptive radiation of endoparasitic cnidarians that have evolved to exploit freshwater, marine and terrestrial hosts. Buddenbrockia is unique in retaining morphological features that have otherwise been lost in the rest of the Myxozoa. In particular, Buddenbrockia possesses a set of 4 muscle blocks that run the length of the worm. The muscle configuration and associated movements of Buddenbrockia are reminiscent of nematodes. However, our confocal studies reveal a unique muscle architecture involving slightly obliquely-orientated muscle fibres within each muscle block and an intervening row of cells rich in circumferentially-orientated actin filaments between the muscle blocks. Videos reveal that the movements effected by this muscle system are not characteristic of nematodes. Here we consider how the muscle architecture of Buddenbrockia provides a foundation for movement that differs from systems utilised in other worm-like/soft bodied animals (conventional hydrostatic skeletons, muscular hydrostats). Buddenbrockia illustrates a novel solution to being a worm by cobbling together elements derived from a limited cnidarian morphological toolkit.