1. Department of Earth Sciences, Palaeobiology; Uppsala University; Villavägen 16 SE-752 36 Uppsala Sweden
2. Department of Palaeozoology; Swedish Museum of Natural History; Box 50007 SE-104 05 Stockholm Sweden
3. Department of Biological Sciences; Macquarie University; Sydney NSW 2109 Australia
4. School of Geographical and Earth Sciences; University of Glasgow; Glasgow G12 8QQ UK
5. Geological Museum; Øster Volgade 5-7 DK-1350 Copenhagen Denmark