The type species, Vetulicola cuneata has a body composed of two distinct parts of approximately equal length. The anterior part is rectangular with a carapace-like structure of four rigid cuticular plates, with a large mouth at the front end. The posterior section is slender, strongly cuticularised and placed dorsally. Paired openings connecting the pharynx to the outside run down the sides. These features are interpreted as possible primitive gill slits. Vetulicola cuneata could be up to 9 cm long. The Vetulicola are thought to have been swimmers that were either filter feeders or detritivores. Other Vetulicola species described are Vetulicola rectangulata, V. gantoucunensis, V. monile, and V. longbaoshanensis. The mouth openings of all the other species are smaller, and do not protrude as in V. cuneata. All other species, with the stark exception of V. gantoucunensis, are smaller than the type species.
Taxonomy
Vetulicola's taxonomic position is controversial. Vetulicola cuneata was originally assigned to the crustaceans on the assumption that it was a bivalved arthropod like Canadaspis and Waptia, but the lack of legs, the presence of gill slits, and the four plates in the "carapace" were unlike any known arthropod. Shu et al. placed Vetulicola in the new family Vetulicolidae, order Vetulicolida and phylumVetulicolia, among the deuterostomes. Shu later argued that the vetulicolians were an early, specialized side-branch of deuterostomes. Dominguez and Jefferies classify Vetulicola as an urochordate, and probably a stem-group appendicularian. In contrast, Butterfield placesVetulicola among the arthropods. The discovery of the related Australian vetulicolian Nesonektris, from the Lower CambrianEmu Bay Shale of Kangaroo Island, and the reidentification of the "coiled gut" of vetulicolians as being a notochord affirms the identification as an urochordate.
Etymology
Vetulicola is a compound Latin word composed of vetuli, meaning "old," or "ancient," and cola, meaning "inhabitant."
