Bibliographic Detail
Horiguichi, T. & Ohtsuka, S., 2001
Reference:
Horiguichi, T. & Ohtsuka, S. (2001). Oodinium inlandicum sp. nov. (Blastodiniales, Dinophyta), a new ectoparasitic dinoflagellate infecting a chaetognath, Sagitta crassa. Plankton Biology and Ecology 48(2): 85-95.
Abstract:
A new ectoparasitic dinoflagellate, Oodinium inlandicum Horiguchi et Ohtsuka sp. nov. in
festing a neritic chaetognath, Sagitta crassa Tokioka is described from the Seto Inland Sea, western
Japan. This is the first record of the genus Oodinium in the western North Pacific. The new species is
readily distinguished from other congeners by: (1) host specificity; (2) the shape and location of the
nucleus; and (3) the morphology of the peduncle. The present study has revealed that as develop
ment proceeds, the nucleus and cytoplasm change markedly. The cytoplasm of the mature trophont
consists of a central endoplasm, rich in cytosol and a highly membranous exoplasm. The nucleoplasm
is uniform and lacks electron dense structures, such as chromosomes. In contrast, the young
trophont has an elongated dinokaryotic nucleus, which almost completely occupies the anterior half
of the cytoplasm. The peduncle penetrates host tissue, but mechanical damage caused by the para
site seems not to be extensive. The comparative ultrastructure and ecology of the new parasite are
also discussed.
