A living fortress Plationus patulus (rotifer)

A well-defended creature. Plationus is a fairly new genus of rotifer, within the family Brachionidae (Segers et al, 1993). Recent molecular analysis supports the separateness and monophyly of Plationus (Reyna-Fabián, 2010). The species P. patulus, first described by Mueller in 1786, was formerly known under the names Brachionus patulus and Platyias patulus. From a microbe aquarium stocked with water from the Mer Bleue bog, in Ottawa, Ont.