Reconstruction of Banffia constricta.
© Marianne Collins
Banffia is regarded to be an end member of a larger group called the vetulicolids, in its own class, the Banffozoa (Caron, 2005). Contrary to most vetulicolids, Banffia lacks anterior grooves and lateral pouches. The position of the vetulicolids is still uncertain (Aldridge et al., 2007).
Banffia – from the town of Banff in Banff National Park. The name comes from the County of Banff in Scotland and was given by Sir William Van Horne in 1888.
constricta – from the Latin con, “a cone,” and strictus, “tight.” The name refers to the constriction in the middle of the cone-shaped body.
Burgess Shale and vicinity: none.
Other deposits: Banffia confusa from the Lower Cambrian Chengjiang Fauna in China (Chen et al., 1996).
The Raymond and Collins Quarries on Fossil Ridge.
Banffia was first described by Walcott based on a half a dozen specimens in a 1911 monograph dealing with various Burgess Shale worms. Walcott placed Banffia in a now defunct group called the Gephyrea with other vermiform fossils such as Pikaia and Oesia. Banffia was later considered to be a Problematica i.e., organism of unknown affinity (Briggs and Conway Morris, 1986). Caron (2005) redescribed this organism based on the original Walcott material and more than 300 specimens collected by the Royal Ontario Museum.
The body can reach up to 10 cm in length and is divided into two broad sections of roughly equal length. The front section has two fused and smooth carapaces forming approximately a tube in cross section. The posterior section is finely segmented with up to 50 segments and is clearly more flexible than the anterior section. The mouth is at the front with a crown-like element around it and the anus is terminal and ends between a small caudal notch. Possible small diverticulae are present around the gut. The entire body is twisted along a spiral, turning clockwise as seen from the front. As a result of this body plan, constrictions are evident in the anterior and posterior parts, especially when specimens are preserved laterally.
Overall Banffia is rare. A few specimens are known from the Raymond Quarry but Banffia is more common in the upper layers of the Collins Quarry on Fossil Ridge. A single slab (350 cm²) from this locality shows more than 60 specimens preserved on it.
The lack of appendages and the bulky anterior section suggest the animal was not a swimmer but lived at the bottom of the sea on the mud itself. The flexible posterior section of the animal would have helped in locomotion. The presence of mud in the gut suggests the animal ate small particles of organic matter present in the flocculent layer of the mud. However because of the large anterior carapaces, this animal was probably not an efficient burrower.
ALDRIDGE, R. J., X. G. HOU, D. J. SIVETER, D. J. SIVETER AND S. E. GABBOTT. 2007. The systematics and phylogenetic relationships of vetulicolians. Palaeontology, 50: 131-168.
BRIGGS, D. E. G. AND S. CONWAY MORRIS. 1986. Problematica from the Middle Cambrian Burgess Shale of British Columbia, p. 167-183. In A. Hoffman and M. H. Nitecki (eds.), Problematic fossil taxa (Oxford Monographs on Geology and Geophysics No. 5). Oxford University Press and Clarendon Press, New York.
CARON, J.-B. 2005. Banffia constricta, a putative vetulicolid from the Middle Cambrian Burgess Shale. Transactions of the Royal Society of Edinburgh, 96: 95-111.
CHEN, J. Y., G. Q. ZHOU, M. Y. ZHU AND K. Y. YEH. 1996. The Chengjiang biota a unique window of the Cambrian explosion. National Museum of Natural Science Taiwan, Taichung, 230 p.
WALCOTT, C. 1911. Cambrian Geology and Paleontology II. Middle Cambrian annelids. Smithsonian Miscellaneous Collections, 57(5): 109-145.