Temporal range: Early Cambrian–Early Ordovician
An advanced X-ray imaging technique called called X-ray tomographic microscopy has been applied to splendidly preserved, uncrushed Markuelia fossils found in Hunan province in southern China and in eastern Siberia. When details in features smaller than one micrometre across can be observed, these fossils are seen to represent many developmental stages, from the first cell divisions to the time of hatching; therefore they offer a unique opportunity to study the development of Lower Cambrian animals.
The features observed indicate that the genus had a mouth surrounded by a ring of teeth (suggesting a carnivorous diet), an alimentary canal, and an anus - being the earliest known examples of this set of features.
However the characters preserved are inconclusive regarding the genus' taxonomic affinity; it can at best be placed in the scalidophoran total group, since it is currently impossible to ally it with the Priapulids or other scalidophora.
Zhang, X. G.; Pratt, B. R.; Shen, C. (2011). "Embryonic Development of a Middle Cambrian (500 Myr Old) Scalidophoran Worm". Journal of Paleontology 85 (5): 898. doi:10.1666/11-024.1. Duan, B.; Dong, X. -P.; Donoghue, P. C. J. (2012). "New palaeoscolecid worms from the Furongian (upper Cambrian) of Hunan, South China: Is Markuelia an embryonic palaeoscolecid?". Palaeontology 55 (3): 613. doi:10.1111/j.1475-4983.2012.01148.x.
- Dong, X. ‐P.; Bengtson, S.; Gostling, N. J.; Cunningham, J. A.; Harvey, T. H. P.; Kouchinsky, A.; Val’Kov, A. K.; Repetski, J. E.; Stampanoni, M.; Marone, F.; Donoghue, P. C. J. (2010). "The anatomy, taphonomy, taxonomy and systematic affinity of Markuelia: Early Cambrian to Early Ordovician scalidophorans". Palaeontology 53 (6): 1291–1314. doi:10.1111/j.1475-4983.2010.01006.x.
- David Attenborough, First life, Episode 1, BBC
|This invertebrate-related article is a stub. You can help Wikipedia by expanding it.|