Markuelia

Markuelia Temporal range: Early Cambrian–Early Ordovician[1] PreЄ Є O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
total group:	Scalidophora
Genus:	Markuelia
Species
M. secunda Val’kov M. hunanensis Dong and Donoghue M. lauriei Haug et al. M. spinulifera Dong et al., 2010 M. waloszeki Dong et al., 2010

Markuelia is a genus of fossil worm-like bilaterian animals allied to Ecdysozoa and known from strata of Lower Cambrian to Lower Ordovician age containing five species.

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.^[2]

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.^[1]

Further reading

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.  edit

References

1. ^ ^{a b} Dong, X. ‐P.; Bengtson, S.; Gostling, N. J.; Cunningham, J. A.; Harvey, T. H. P.; Kouchinsky, A.; Val’kov, A. K.; Repetski, J. E. et al. (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.  edit
2. ^ David Attenborough, First life, Episode 1, BBC

• Geotimes"Fossil embryos exposed in 3-D" October 2006
• Dr Philip Donoghue, "Markuelia"