growth dynamics of australias polar dinosaurs澳大利亚经济增长动力的极地恐龙.pdfVIP

Growth Dynamics of Australia’s Polar Dinosaurs 1 2,4 3 4 Holly N. Woodward *, Thomas H. Rich , Anusuya Chinsamy , Patricia Vickers-Rich 1 Museum of the Rockies, Montana State University, Bozeman, Montana, United States of America, 2 Museum Victoria, Melbourne, Victoria, Australia, 3 Zoology Department, University of Cape Town, Rhodes Gift, South Africa, 4 School of Geosciences, Monash University, Clayton, Victoria, Australia Abstract Analysis of bone microstructure in ornithopod and theropod dinosaurs from Victoria, Australia, documents ontogenetic changes, providing insight into the dinosaurs’ successful habitation of Cretaceous Antarctic environments. Woven-fibered bone tissue in the smallest specimens indicates rapid growth rates during early ontogeny. Later ontogeny is marked by parallel-fibered tissue, suggesting reduced growth rates approaching skeletal maturity. Bone microstructure similarities between the ornithopods and theropods, including the presence of LAGs in each group, suggest there is no osteohistologic evidence supporting the hypothesis that polar theropods hibernated seasonally. Results instead suggest high-latitude dinosaurs had growth trajectories similar to their lower-latitude relatives and thus, rapid early ontogenetic growth and the cyclical suspensions of growth inherent in the theropod and ornithopod lineages enabled them to successfully exploit polar regions. Citation: Woodward HN, Rich TH, Chinsamy A, Vickers-Rich P (2011) Growth Dynamics of Australia’s Polar Dinosaurs. PLoS ONE 6(8): e23339. doi:10.1371/ journal.pone.0023339 Editor: Andrew Allen Farke, Raymond M. Alf Museum of Paleontology, United States of America Received April 11, 20