BioEssays 10/2021

With their very simple body plan and small genome, Placozoans are considered to be the simplest metazoan. They may therefore serve as a potential model for the ancestral state of metazoan organization. So far, only three species have been formally described in this phylum. Two articles in this issue of BioEssays take a closer look at these enigmatic organisms. In article 2100080 Bernd Schierwater and colleagues review Placozoan biology including their diversity and distribution, the Placozoan life cycle as well as their systematic position. In article 2100083, the same authors discuss how Placozoans may be used as model systems e.g. for gravitational biology and cancer research.