Xenambulacraria
Xenambulacraria is a proposed clade of animals with bilateral symmetry as an embryo, consisting of the Xenacoelomorpha and the Ambulacraria.
If confirmed, the clade would either be the sister group to the chordates or the sister group to all the other bilaterians, grouped together in Centroneuralia.
Although the validity of the clade relies mostly on phylogenomics, molecular genetics studies have proposed pigment cell clusters expressing polyketide synthase and sulfotransferase as a synapomorphy of Xenambulacraria.