linguistic:voice_change, quality:corruption
Vetulicolia is a phylum of bilaterian animals encompassing several extinct species belonging to the Cambrian period. The phylum was created by Degan Shu and his research team in 2001, and named after Vetulicola cuneata, the first species of the phylum described in 1987. The vetulicolian body plan comprises two parts: a voluminous rostral (anterior) forebody, tipped with an anteriorly positioned mouth and lined with a lateral row of five round to oval-shaped openings on each side, which have been interpreted as gills; and a caudal (posterior) section that primitively comprises seven body segments and functions as a tail. All vetulicolians lack preserved appendages of any kind, having no legs, feelers or even eye spots. The area where the anterior and posterior parts join is constricted. Their taxonomic affinity has been uncertain; they have been interpreted as stem- and crown-group arthropods, stem-group vertebrates, and early deuterostomes. The general scientific consensus before 2001 considered them early limbless arthropods but now considers them early deuterostomes. Vetulicolian fossils examined in 2014 show the presence of notochord-like structures, and it was concluded that vetulicolians are crown-group chordates and probably related to modern tunicates. Research from 2017 rather indicates vetulicolians are related to Saccorhytus, another basal deuterostome group, although another study shows possibility that Saccorhytus is ecdysozoan instead of deuterostome.