Yuyuanozoon magnificissimi is the largest known vetulicolian, with the holotype (and only known specimen) measuring about 202 millimeters in length.[1] Its body consists of an egg-shaped anterior (front) section and a thinner, cylindrical posterior (rear) section. The anterior section is divided into 6 segments, with a gill opening (that had gill filaments extending out from each opening) placed symmetrically on each side of every body segment starting at the second segment. The posterior section is divided into 7 segments, and differs from the posterior sections of all other known vetulicolians (not being flattened like in vetulicolids like Vetulicola, not oar-like or leaf-like as in didazoonids like Didazoon, and also unlike those of banffozoans like Banffia and Skeemella).
The shape of the posterior body, and the gill openings with gill filaments, currently leave Y. magnificissimi as incertae sedis within Vetulicolia.
Etymology
The generic name translates as "Animal of Yu Yuan," Yu Yuan being an ancient name for Chengjiang County. The specific name, magnificissimi, translates as "magnificent," in reference to the great size of the holotype.
