A minor phylum that contains a single minute marine invertebrate ("Trichoplax adhaerens"), which has a flattened body with two cell layers and is the simplest known metazoan.
- ‘Of particular interest in this regard are animals in the early diverging non-bilaterian phyla Porifera, Placozoa, Cnidaria, and Ctenophora.’
- ‘Presently, many species are highlighted for study because of their membership in Cnidaria, Ctenophora, Placozoa, or Porifera.’
- ‘Despite these attempts, relationships among Bilateria, Cnidaria, Ctenophora, Placozoa, and Porifera remain obscure.’
- ‘The phylum Placozoa, with its single described species Trichoplax adhaerens, is of great interest to students of metazoan evolution because of its simple composition and its resistance to secure placement within the metazoan tree.’
- ‘Increasing evolutionary diversity for comparative genomics to early-emerging multicellular animals (e.g., Porifera, Placozoa, Cnidaria, Ctenophora) may help to decipher animal origins.’
Modern Latin (plural), from Greek plakos flat + zōia animals.
We take a look at several popular, though confusing, punctuation marks.