Rotifera, Acanthocephala and Seisonida make up a clade called Syndermata.
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A phylum including: rotifers
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Phylum of microscopic, transparent animals distinguished by rings of cilia around the anterior end, which cause the appearance of whirling. Rotifers are abundant in the plankton community and are important for nutrient recycling in aquatic systems.
Organ System, bilateral symmetry, pseudocoelom, no circulatory, simple brain; crown of cilia