Bell Alyssa, Chiappe Luis M
The Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, California, United States of America.
PLoS One. 2015 Nov 18;10(11):e0141690. doi: 10.1371/journal.pone.0141690. eCollection 2015.
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.
美国堪萨斯州尼奥布拉拉白垩层的斯莫基希尔段产出了众多黄昏鸟目的遗骸，黄昏鸟目是一种从早白垩世晚期到晚白垩世的有齿潜水鸟类。本研究提出了一种来自斯莫基希尔段的新黄昏鸟目分类单元，霍夫曼烟熏黄昏鸟（Fumicollis hoffmani），其正模标本是较为完整的黄昏鸟目骨骼之一。烟熏黄昏鸟具有原始（例如股骨近端和远端未扩展、髋臼前髂骨延长、髌骨小且呈金字塔形）和衍生（例如第四跖骨上的背嵴、第三趾骨远端骨干的跖侧突出曲线）黄昏鸟目特征的独特组合，这表明它比像近黄昏鸟（Baptornis advenus）这样的小型黄昏鸟目更特化，但不像大型的帝王黄昏鸟（Hesperornis regalis）那样高度衍生。烟熏黄昏鸟的鉴定再次凸显了晚白垩世西部内陆海道中存在的黄昏鸟目显著多样性。这种多样性表明存在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特化所表明的那样。
