urostylida urostylida urostylida is an order of littoral ciliates. the taxonomy of the order is largely unresolved and still subject to scientific inquiry. urostylida scientific classification domain: eukaryota clade: diaphoretickes clade: sar clade: alveolata phylum: ciliophora class: hypotrichea order: urostylidajankowski, 1979 families see text families according to the catalogue of life, nine families are accepted within holosticha. bakuellidae holostichidae kahliellidae pseudokeronopsidae pseudourostylidae psilotrichidae rigidothrichidae trachelostylidae urostylidae