Planulozoa

Planulozoa is a clade of animals that includes the superphyla Cnidaria (jellyfish, hydrozoans, sea anemones, corals, etc.) and the Bilateria (all complex animals with bilateral symmetry, including arthropods, molluscs, vertebrates, etc.).^[2][3] The designation Planulozoa may be considered a synonym to ParaHoxozoa, which also contains Placozoa. Within Planulozoa, the Placozoa may be a sister of Cnidaria to the exclusion of Bilateria.^[4][5][6][7] The clade excludes basal animals such as the Ctenophora (comb jellies),^[8][9][3] and Porifera (sponges).^[10][11][12] Although this clade was sometimes used to specify a clade of Cnidaria and Bilateria to the exclusion of Placozoa (against the original intention of its proposal), this is no longer favoured due to recent data indicating a sister group relationship between Cnidaria and Placozoa,^[13] another study still supports Placozoa as sister to Cnidaria+Bilateria.^[14]

Planulozoa Temporal range: 600–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Diversity of planulozoans
Scientific classification
Kingdom:	Animalia
Subkingdom:	Eumetazoa
(unranked):	ParaHoxozoa
(unranked):	Planulozoa Wallberg et al., 2004
Phyla
Cnidaria Bilateria/Triploblasta Proarticulata †? Xenacoelomorpha Kimberella† Tullimonstrum† Saccorhytida †[1] Nephrozoa (unranked) Superphylum Deuterostomia Chordata (s.l) Vetulicolia† Cephalochordata Craniata "Ambulacraria" Hemichordata Echinodermata Cambroernida† Vetulocystidae† Protostomia (unranked) Superphylum Ecdysozoa Spiralia (unranked) Ctenophora? (Biradial symmetry makes possible classification here) Placozoa?

The phylogenetic tree indicates approximately how many millions of years ago (mya) the lineages split. Here, Planulozoa is shown sans Placozoa.^[15][16][17]

Planulozoa are associated with the emergence of the Zoc and ZF-NC gene domains.^[18]

Choanozoa	Choanoflagellata Animalia Porifera Eumetazoa Ctenophora ParaHoxozoa Placozoa Planulozoa Cnidaria Bilateria Xenacoelomorpha Nephrozoa Deuterostomia Ambulacraria Chordata Protostomia Ecdysozoa Spiralia 610 mya 650 mya Triploblasts 680 mya Diploblasts 760 mya
950 mya