This is the smallest of all animal databases yet; it contains a single nominal species, Trichoplax adhaerens. A second species that is sometimes mentioned, Treptoplax reptans, has never been found again after its first and only report and is most likely a fragmented placozoan [2]. With only one species the phylum knows only three taxonomic ranks: Phylum (Placozoa), genus (Trichoplax), and species (T. adhaerens). This situation is soon to change radically. Genetic analyses have suggested that Placozoa harbor at least seven major species clades, which may represent different orders, each with multiple families.
The placozoan species database will be updated immediately when a relevant manuscript becomes accepted. Please send information to Bernd Schierwater.