Identification of a New Hesperornithiform from the Cretaceous Niobrara Chalk and Implications for Ecologic Diversity among Early Diving Birds.
Identification of a New Hesperornithiform from the Cretaceous Niobrara Chalk and Implications for Ecologic Diversity among Early Diving Birds.
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DOI：
10.1371/journal.pone.0141690
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Chiappe LM
中科院分区：
文献类型：
--
作者：
Bell A;Chiappe LM
美国堪萨斯州Niobrara白垩的Smoky Hill成员已经发现了许多hesperornithformes成员的遗骸，这些成员是早白垩纪晚期到晚白垩纪的牙齿潜水鸟。本研究提出了一个来自烟山成员的新分类群，Fumicollis hoffmani，其完整模式是较完整的hesperornithform骨骼之一。Fumicollis具有独特的原始（如股骨近端和远端未扩张，延长的髋臼前髂骨，小而锥形的髌骨）和衍生（如跖骨4的背脊，指骨3远轴的植物投射曲线：1）的特征，表明它比小的hesperornithform（如Baptornis advenus）更专门化，但不像大的Hesperornis regalis那么高度衍生。Fumicollis的发现再次强调了晚白垩纪西部内陆海道存在的高鸟类的显著多样性。这种多样性表明存在着一个复杂的生态系统，也许具有高度的生态位划分，正如这些鸟类不同程度的潜水专业化所表明的那样。
The Smoky Hill Member of the Niobrara Chalk in Kansas (USA) has yielded the remains of numerous members of the Hesperornithiformes, toothed diving birds from the late Early to Late Cretaceous. This study presents a new taxon of hesperornithiform from the Smoky Hill Member, Fumicollis hoffmani, the holotype of which is among the more complete hesperornithiform skeletons. Fumicollis has a unique combination of primitive (e.g. proximal and distal ends of femur not expanded, elongate pre-acetabular ilium, small and pyramidal patella) and derived (e.g. dorsal ridge on metatarsal IV, plantarly-projected curve in the distal shaft of phalanx III:1) hesperornithiform characters, suggesting it was more specialized than small hesperornithiforms like Baptornis advenus but not as highly derived as the larger Hesperornis regalis. The identification of Fumicollis highlights once again the significant diversity of hesperornithiforms that existed in the Late Cretaceous Western Interior Seaway. This diversity points to the existence of a complex ecosystem, perhaps with a high degree of niche partitioning, as indicated by the varying degrees of diving specializations among these birds.