Morphology and ontogenesis of Platyophrya bromelicola nov. spec., a new macrostome-forming colpodid (Protists, Ciliophora) from tank bromeliads of Jamaica.

Platyophrya bromelicola nov. spec. was discovered in tanks of bromeliads from Jamaica. Its morphology, ontogenesis, and small-subunit rDNA were studied using standard methods. Platyophrya bromelicola differs from its congeners mainly by the pyriform, unflattened body (vs. reniform and flattened); the free-swimming (planktonic) habit (vs. biofilm creepers); and the unique ability to form two distinct morphs, i.e., small, bacteriophagous microstomes and large, predaceous macrostomes. Microstomes and macrostomes can be distinguished not only by body size and feeding preferences but also by the postoral pseudomembrane composed of two vs. three to four dikinetids per kinety. The ability to form macrostomes is considered as an adaptation to the highly competitive habitat. Ontogenesis closely resembles that of other members of the family. Platyophrya bromelicola is distinct not only morphologically but also genetically (3.7% in the small-subunit rDNA) from P. vorax, a common, cosmopolitan moss and soil species.