KYAROIKEUS-CETARIUS N-G, N-SP - A PARASITIC CILIATE FROM THE RESPIRATORY-TRACT OF ODONTICETE CETACEA

Examination of mucus discharged from the blowholes of live odonticete Cetacea and material collected from nasal orifices of dead hosts routi nely revealed infestations of a large spindle-shaped ciliate, Kyaroike us cetarius n. g., n. sp. These ciliates had a prominent posterior pod ite and were holotrichously ciliated except for a conspicuous bipolar stripe extending along the left margin of the cell. Most specimens wer e free-swimming and moved slowly through freshly collected mucus, but some individuals were attached to host cells or cellular debris by a t ransparent thread secreted from the podite. The oral architecture of p rotargol-impregnated K. cetarius consisted of one preoral and two circ umoral kineties set within a deep oral cavity continuous with an exten sive, posteriorly directed cytopharynx. Somatic kineties were composed entirely of monokinetids and formed an expansive right ciliary field covering most of the cell surface, a reduced left ciliary field adjace nt to the oral cavity, and a group of four kinetal fragments located m id-ventrally within a shallow pocket. Subkinetal microtubules were ass ociated with the kineties of the right and left fields, and the non-ci liated stripe was underlain by a series of longitudinal fibers. The ci liate's large, heteromeric macronucleus was centrally positioned and c learly evident in living or stained specimens, while the ellipsoid mic ronucleus was located adjacent to the cytopharynx and often inconspicu ous. K. cetarius has several morphological attributes typical of phyll opharyngian ciliates (e.g., adhesive organelle, heteromeric macronucle us, somatic kineties of monokinetids, subkinetal microtubules), and, e xcept for its nearly holotrichous ciliation, most closely resembles dy steriine ciliates.