Charles J. O'Kelly
Laboratory for Ocean Sciences, West Boothbay Harbor, Maine, USA
Thomas A. Nerad
Protistology Department, American Type Culture
Collection, Rockville, Maryland, USA
European Journal of Protistology (in press)
The kinetid of the common marine heterotrophic nanoflagellate Caecitellus parvulus (Griessmann, 1913) Patterson et al., 1993 is essentially identical to those found in members of the stramenopile protist order Bicosoecida (= Bicosoecales) in absolute configuration, microtubular root characters, especially those of root R3, and the structure and arrangement of bands connecting the basal bodies to each other and to the microtubular roots. Caecitellus parvulus, originally assigned to the bodonids (as Bodo parvulus), is therefore considered to be allied with the Bicosoecida. The characters distinguishing the genus Caecitellus from other bicosoecids include the presence of gliding motility and a raptorial feeding mechanism, as well as the absence of flagellar hairs, a filter feeding mechanism, and the ability to adhere to substrate by the tip of the posterior flagellum. These results suggest that the stramenopile clade that includes bicosoecids and Caecitellus is likely to contain much additional taxonomic, morphological and ecological diversity.