1. Natural History Museum, Cromwell Road, London SW7 5BD, United Kingdom,
2. Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA,
3. Milner Centre for Evolution, University of Bath, Claverton Down, Bath, BA2 7AY, United Kingdom,
4. Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, Bristol, BS8 1TQ, United Kingdom,