[1] CNRS MNHN UPMC, Museum Natl Hist Nat, Ctr Rech Paleobiodiversite & Paleoenvironm, Dept Hist Terre,UMR 7207, F-75231 Paris 05, France
[2] Smithsonian Inst, Natl Museum Nat Hist, Dept Paleobiol, Washington, DC 20013 USA
[3] Cape Breton Univ, Dept Biol, Sydney, NS B1P 6L2, Canada
[4] Royal Ontario Museum, Dept Nat Hist, Toronto, ON M5S 2C6, Canada