• Introduction
  • Meaning of Orsten
  • Orsten fossils
  • K. Müller
  • Abundance
  • Other Orsten evidence
• Methods
  • Processing
  • SEM work
  • Stereo images
  • 3D modelling
• History
• Worldwide
• Publications
• Projects
  • Running
  • Finished
  • Envisaged
• Orsten Fossils
  • Gallery
  • Taxa
• Systematics
  • Start page
  • Evolutionary Implications
  • Eucrustaceans
  • Phosphatocopines
  • Stemcrustaceans
  • Euarthropods
  • Stem arthropods
• Other Fossils in Orsten Rocks
• Collaborations

Activities

• scientific
  • Ulm team
  • Leicester team
• non-scientific
• Fun pics

Publicity/Dissemination

Become a C.O.R.E. Supporter

Visit the 'Orsten' "Fan" Corner

Current Scientific Activities of the Leicester Team, September, 2009

Over the past year, the team based in Leicester, UK, has been reinvestigating the early Cambrian Comley limestones of Shropshire, England. This important and historic succession has yielded some of the earliest examples of exceptionally preserved 'Orsten'-type fossil arthropods, providing key insights into early crustacean evolution.

History of research

The Comley limestones form part of a classic Cambrian succession, and have been the subject of palaeontological research for more than 100 years. However, it is only relatively recently, during extensive processing of the limestones for acid-resistant microfossils undertaken by Hinz (1987), that the exceptionally preserved Orsten-type arthropods came to light. These fossils inspired a targeted investigation by Leicester palaeontologists Mark Williams and David Siveter in 1994, during which a trench section was excavated close to the historic locality of Cobbold (1927) in order to expose the arthropod-bearing limestone horizons. Acid maceration of these samples provided new and better material of exceptionally preserved phosphatocopid arthropods, allowing the detailed description of a new taxon – Klausmuelleria salopensis – in collaboration with Dieter Waloszek (Siveter et al. 2001, 2003).

Current research

Current research into the Comley limestones by a Leicester-based team aims to build on previous results to extend knowledge of the palaeobiology and taphonomy of the exceptionally preserved arthropods. In September 2008, the key horizons were re-excavated in a trench section by Mark Williams and David Siveter, now working together with postdoctoral research associate Tom Harvey and colleagues Philip Wilby (British Geological Survey, Keyworth), Sarah Gabbott (Leicester), Phil Donoghue (Bristol) and Dieter Waloszek (Ulm).
More than a tonne of rock was extracted – with a little help from a mechanical digger – and this is now being processed in the acid laboratory in Leicester. Bulk processing of the limestones to yield new fossil material is being accompanied by detailed analysis of the wider geological setting of the Comley Lagerstätte. Ongoing projects include macrofossil identification for a refined biostratigraphy (with Adrian Rushton, London), geochemical contexts (with Dan Condon and Melanie Leng, British Geological Survey), and high-resolution petrographic and EDX studies to reconstruct the depositional and diagenetic environments, with a focus on exceptional phosphatic preservation.

Preliminary results

Many kilograms of Comley limestone have now been processed in the laboratory, and thousands of microfossils have been picked from the residues. Alongside a diversity of ‘small shelly fossils’, the new specimens include further examples of phosphatocopid arthropods exhibiting soft-part preservation – confirming the Comley limestones as a key early Cambrian source of Orsten-type fossils – plus various additional and previously unknown phosphatized forms including crumpled (possibly pelletized) fragments of bradoriid arthropods, and possible fossil embryos.
Meanwhile, investigation of the depositional and diagenetic environments aided by an assessment of preservational variation among the new collections of microfossils is shedding light on the poorly understood phenomenon of 'Orsten'-style phosphatization.

Preliminary results have been presented at the recent Walcott meeting (International Conference on the Cambrian Explosion, Banff, Canada, August 2009; http://burgess-shale.info). Watch this space for news of further conference presentations and forthcoming publications!

References

• Cobbold, E. S. 1927. The stratigraphy and geological structure of the Cambrian area of Comley (Shropshire). Quarterly Journal of the Geological Society of London 83, 551-573.
• Hinz, I. 1987 The Lower Cambrian microfauna of Comley and Rushton, Shropshire/England. Palaeontographica Abteilung A 198, 41-100.
• Siveter, D. J., Williams, M. & Waloszek, D. 2001. A phosphatocopid crustacean with appendages from the Lower Cambrian. Science 293, 479-481. PDF
• Siveter, D. J., Waloszek, D. & Williams, M. 2003. An early Cambrian phosphatocopid crustacean with three-dimensionally preserved soft parts from Shropshire, England. Special Papers in Palaeontology 70, 9-30. PDF part 1 – PDF part 2

Left: Members of the Leicester team excavating a trench section to expose the fossil-bearing Comley limestones. Upper Right: The phosphatocopid crustacean Klausmuelleria salopensis with preserved body and appendages (holotype; see Siveter et al. 2003). Lower Right: A sclerite of the lobopod Microdictyon, one of a diversity of 'small shelly fossil' taxa preserved in the Comley limestones.