نفروزوآ

Also known as Eubilateria, Nephrozoan, Nephrozoans, Eubilaterian, Eubilaterians

Nephrozoa is a proposed major clade which would contain nearly all living bilaterian animals. Under this hypothesis, Xenacoelomorpha forms the earliest diverging branch of Bilateria, with all other bilaterians placed in Nephrozoa. It contrasts with the Xenambulacraria hypothesis, which instead posits that Xenacoelomorpha is most closely related to Ambulacraria (usually placed as deuterostomes). Which hypothesis is correct has been debated, and as of 2024 the issue is unresolved. The clade is named after a key synapomorphy of the group: the presence of specialized excretory organs known as neph