Placozoa

E443082

Placozoa is a phylum of simple, flat, millimeter-sized marine animals with only a few distinct cell types and no true tissues or organs, considered among the most basal and primitive of all multicellular animals.

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Statements (49)

Predicate Object
instanceOf animal phylum
taxon
bodyPlan dorsoventrally flattened body
bodyShape flat
cellAdhesion simple cell junctions
cellLayerOrganization intermediate fiber cell layer
lower epithelial layer
upper epithelial layer
cellTypeDiversity few distinct cell types
circulatorySystem no circulatory system
commonName placozoans
describedAs simple marine animals
diet bacteria
microalgae
organic detritus
digestiveSystem no true gut
discovery first described in the late 19th century
distribution cosmopolitan in tropical and subtropical seas
domain Eukaryota NERFINISHED
evolutionarySignificance among the simplest known multicellular animals
feedingMode external digestion
phagocytosis
gasExchange diffusion across body surface
genomeFeatures contains many genes shared with other metazoans
relatively small genome
germLayers diploblastic or ambiguous germ layer organization
habitat benthic zone
marine environments
kingdom Animalia
lifestyle free-living
locomotion ciliary gliding
musculature no true muscles
nervousSystem no true nervous system
notableSpecies Trichoplax adhaerens NERFINISHED
organOrganization lacking true organs
osmoregulation diffusion-based
phylogeneticPosition basal metazoans
reproduction asexual reproduction by budding
asexual reproduction by fission
sexual reproduction (poorly understood)
researchUse model for early animal evolution
model for minimal multicellularity
respiratorySystem no specialized respiratory organs
skeleton lacks hard skeleton
substrateAssociation moves along hard substrates
symmetry asymmetrical
taxonRank phylum
tissueOrganization lacking true tissues
typicalSize millimeter-sized

Referenced by (2)

Full triples — surface form annotated when it differs from this entity's canonical label.

Bilateria excludes Placozoa
Nephrozoa excludes Placozoa