Parenchymia is a proposed

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

encompassing '' Nemertea'' and '' Platyhelminthes''. The clade was suggested in a 2019 study showing the clade as a sister to '' Annelida'' and '' Lophophorata''. The

synapomorphies In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have ...

include similar organization of ciliary bands in the larva of both groups, as well as a lack of chitin, and is named for the abundant

parenchyma Parenchyma () is the bulk of functional substance in an animal organ or structure such as a tumour. In zoology it is the name for the tissue that fills the interior of flatworms. Etymology The term ''parenchyma'' is New Latin from the word π ...

found between the body wall and internal organs of both. A similar taxon, with

Mollusca Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

being likewise linked together with '' Symbion'' and '' Entoprocta'', has been proposed in a clade called '' Tetraneuralia''.

References

Protostome taxonomy Lophotrochozoa {{Animal-stub