Marrella was a small creature, measuring 2 centimeters long at most. Its most prominent feature was its head shield, which had two pairs of rear-facing spikes. Marrella walked on the sea floor using around 50 individual legs, with each leg supporting a feathery gill-like structure. In life, the hard parts of Marrella would have been iridescent.
At the current time, Marrella is best classified as a stem group arthropod, and not a type of trilobite as its morphology would suggest.
Marrella was the first type of fossil collected by Charles Walcott from the Burgess Shale in British Columbia. He described it in 1912, identifying it as a possible trilobite. In 1971, Harry Whittington published a redescription of the animal and concluded that Marrella was not actually a trilobite, nor was it part of any extant arthropod group. It was subsequently labeled as a stem group arthropod.
Since its discovery, over 25,000 specimens of Marrella have been collected, making up a significant portion of the specimens found in the Greater Phyllopod bed.
Marrella is thought to have been a deep-sea scavenger, living on the ocean floor and feeding on small particles of organic material. One particular specimen shows that the animal molted its shell, rather like living marine invertebrates.
- ↑ Bottjer, David J; Etter, Walter; Hagadorn, James W; Tang, Carol M (2002). Exceptional Fossil Preservation: A Unique View on the Evolution of Marine Life. Columbia University Press. p. 70. ISBN 978-0-231-10255-1. OCLC 47650949.
- ↑ Parker, A. R. (1998). "Colour in Burgess Shale animals and the effect of light on evolution in the Cambrian". Proceedings of the Royal Society B: Biological Sciences 265 (1400): 967–972. doi:10.1098/rspb.1998.0385.
- ↑ Gould, Stephen Jay (2000). Wonderful Life: Burgess Shale and the Nature of History. Vintage. p. 108. ISBN 978-0-09-927345-5. OCLC 45316756. Also OCLC 44058853.
- ↑ Whittington, H. B. (1971). "Redescription of Marrella splendens (Trilobitoidea) from the Burgess Shale, Middle Cambrian, British Columbia". Bulletin – Geological Survey of Canada (Geological Survey of Canada) 209: 1–24.
- ↑ Caron, J. -B.; Jackson, D. A. (October 2006). "Taphonomy of the Greater Phyllopod Bed community, Burgess Shale". PALAIOS 21 (5): 451–465. doi:10.2110/palo.2003.P05-070R. edit
- ↑ García-Bellido, D. C.; Collins, D. H. (2004). "Moulting arthropod caught in the act". Nature 429 (6987): 40. Bibcode:2004Natur.429...40G. doi:10.1038/429040a. PMID 15129272.