Brownstein Chase D
Research Associate, Stamford Museum and Nature Center, Stamford, CT, United States of America.
PeerJ. 2018 Jun 11;6:e4973. doi: 10.7717/peerj.4973. eCollection 2018.
Direct evidence of paleoecological processes is often rare when the fossil record is poor, as in the case of the Cretaceous of eastern North America. Here, I describe a femur and partial tibia shaft assignable to theropods from two Late Cretaceous sites in New Jersey. The former, identifiable as the femur of a large ornithomimosaur, bears several scores interpreted as shark feeding traces. The tibia shaft has punctures and flaked bone from the bites of mid-sized crocodyliforms, the first documented occurrence of crocodyliform traces on dinosaur bone from the Maastrichtian of the Atlantic Coastal Plain. The surface of the partial tibia is also littered with indentations interpreted as the traces of invertebrates, revealing a microcosm of biological interaction on the coastal seafloor of the Cretaceous Atlantic Ocean. Massive crocodyliforms, such as and the slightly smaller , maintained the role of terrestrial vertebrate taphonomic process drivers in eastern North America during the Cretaceous. The report of crocodyliform bite marks on the ornithomimosaur tibia shaft in this manuscript reinforces the importance of the role of crocodyliforms in the modification of terrestrial vertebrate remains during the Cretaceous in North America. The preserved invertebrate traces add to the sparse record of the presence of barnacles and other marine invertebrates on dinosaur bone, and the evidence of shark feeding on the ornithomimosaur femur support the "bloat-and-float" model of terrestrial vertebrate fossil deposition in marine deposits from the Cretaceous of eastern North America.
当化石记录不佳时，古生态过程的直接证据往往很罕见，就像北美东部白垩纪时期的情况那样。在此，我描述了一根股骨和部分胫骨干，它们可归于新泽西州两个晚白垩世遗址的兽脚亚目恐龙。前者可确定为一只大型似鸟龙的股骨，上面有几处痕迹被解释为鲨鱼的捕食痕迹。胫骨干上有中型鳄形类动物咬痕造成的穿孔和骨片剥落，这是大西洋沿岸平原马斯特里赫特阶恐龙骨上首次有记录的鳄形类痕迹。部分胫骨的表面也布满了被解释为无脊椎动物痕迹的凹痕，揭示了白垩纪大西洋沿海海底生物相互作用的一个微观世界。大型鳄形类动物，如 和稍小一些的 ，在白垩纪时期的北美东部一直是陆地脊椎动物埋藏过程的驱动者。本手稿中关于似鸟龙胫骨干上鳄形类咬痕的报告，强化了鳄形类动物在北美白垩纪时期陆地脊椎动物遗骸变化过程中所起作用的重要性。保存下来的无脊椎动物痕迹增加了恐龙骨上藤壶和其他海洋无脊椎动物存在的稀少记录，而鲨鱼捕食似鸟龙股骨的证据支持了北美东部白垩纪海洋沉积物中陆地脊椎动物化石沉积的“膨胀漂浮”模型。
