Vetulicolia
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Vetulicolia is a phylum erected by Shu, et. al. (2001), encompassing several early-Cambrian fossil forms. They suggest that these animals were early deuterostomes. The bodyplan consists of two parts, a voluminous anterior section with a large "mouth" and a row of five round to oval-shaped features on each side that are interpreted as gills (or at least openings in the vicinity of the pharynx) and a posterior section with seven segments. The area where the anterior and posterior parts join is constricted. The phylum Vetulicolia is defined by Shu, et. al. to include the family Didazoonidae, with the genera Didazoon and Xidazoon, the family Vetulicolidae, with the genera Pomatrum and Vetulicola, and the genus Banffia. The authors also propose that vetulicolians and yunnanozoons may be closely related.
Shu (2003) has argued that the vetulicolians probably represent an early specialized side-branch of deuterostomes, and that this implies that segmentation in cephalochordates and vertebrates may be derived from the common ancestor of protostomes and deuterostomes.
References
- Shu, D.-G., Conway Morris, S., Han, J., Chen, L., Zhang, X.-L., Zhang, Z.-F., Liu, H.-Q., Li, Y., and Liu, J.-N. 2001. Primitive Deuterostomes from the Chengjiang Lagerstätte (Lower Cambrian, China), Nature, 414:419-424. (November 11 2001). [1].
- Shu, Degan. 2003. A paleontological perspective of vertebrate origin. Chinese Science Bulletin, Vol. 48 No. 8 725-735. April, 2003. [2]