Vetulicolia is an extinct
taxon, either
phylum or subphylum in rank, encompassing several
Cambrian organisms. The vetulicolian body comprises two parts: a voluminous anterior forebody, tipped with an anteriorly positioned mouth, and lined with a row of five round to oval-shaped features on each lateral side, which have been interpreted as
gills - or at least openings in the vicinity of the
pharynx, and a
posterior section that primitively comprises seven segments, and functions as a tail. All vetulicolians lack preserved appendages of any kind, having no legs, feelers, or even eyes. The area where the anterior and posterior parts join is constricted. Their affinity has been uncertain; they have been considered to represent stem- and crown-group arthropods, stem-group vertebrates, and early
deuterostomes. The general scientific consensus formerly (before 2001) considered them early limbless arthropods, but now considers them early deuterostomes. Recently examined Vetulicolian fossils show the presence of
notochord-like structures. Therefore, it can be concluded that vetulicolians are crown-group
chordates and probably the sister group of modern
tunicates.
