1. Department of Earth Sciences (Palaeobiology); Uppsala University; Villavägen 16 SE-75236 Uppsala Sweden
2. School of Earth, Atmospheric and Environmental Sciences; The University of Manchester; Manchester M13 9PL UK
3. Department of Natural History (Palaeobiology Section); Royal Ontario Museum; 100 Queen's Park Toronto Ontario Canada M5S2C6
4. Department of Ecology and Evolutionary Biology; University of Toronto; 25 Willcocks Street Toronto Ontario Canada M5S 3B2
5. Department of Earth Sciences; University of Toronto; 22 Russell Street Toronto Ontario Canada M5S 3B1