ULTRASTRUCTURE AND IDENTIFICATION OF THE PREDATORY FLAGELLATE COLPODELLA-PUGNAX CIENKOWSKI (APICOMPLEXA) WITH A DESCRIPTION OF COLPODELLA-TURPIS N-SP AND A REVIEW OF THE GENUS

A flagellated predator of the chlorophyte alga Dunaliella spp. was exa mined by light and electron microscopy. Although this predator had pre viously been identified as a species of the kinetoplastid genus Bodo, the present study revealed the flagellate to be indistinguishable from Colpodella pugnax, the type-species for its genus. The flagellate lac ks a kinetoplast, a microtubule supported cytopharynx and paraxial rod s in the flagella - characters universally found in kinetoplastid flag ellates. The cell has mitochondria with vesicular cristae. Multiple me mbranes surround the cell and are underlain by longitudinal microtubul es not originating from the flagellar region. Most notably, the flagel late has micropores and an apical complex including a conoid, sacculat e rhoptries and, apparently, a polar ring. This study has confirmed th at Colpodella is the genus with free-living species most closely relat ed to the apicomplexan parasites (i.e. the ''Euapicomplexa'' and Perki nsus). No unambiguous synapomorphy supports an ''apicomplexan parasite s'' clade: Inclusion of Colpodella is necessary to secure the Apicompl exa as a monophyletic (=holophyletic) taxon. A new family, the Colpode llidae, is erected for this genus. Colpodella turpis, a previously und escribed species that also consumes Dunaliella spp., was isolated frot h the same samples as C. pugnax. A diagnosis for this species is prese nted together with a brief review of the genus, in which we recognise seven species. The generic names Alphamonas Alexeieff, Nephromonas Dro op and Dingensia Patterson & Zolffel are rendered into synonomy with C olpodella.