Wick Steven L, Lehman Thomas M
Division of Science and Resource Management, Big Bend National Park, TX 79834, USA.
Naturwissenschaften. 2013 Jul;100(7):667-82. doi: 10.1007/s00114-013-1063-0. Epub 2013 Jun 1.
Bravoceratops polyphemus gen. et sp. nov. is a large chasmosaurine ceratopsid from the lowermost part of the Javelina Formation (early Maastrichtian) of Big Bend National Park, TX, USA. B. polyphemus has a distinctive narrow snout, a long fenestrate frill, and a fan-shaped median parietal bar with a midline epiparietal on its posterior margin, as well as a symmetrical depression on its dorsal surface at the nexus of the parietal rami. This depression is interpreted to be the attachment point for a second midline epiparietal. This parietal morphology is distinct from that exhibited by Anchiceratops or Pentaceratops. The posterior midline epiparietal in B. polyphemus and its bifurcated quadratojugal-squamosal joint are features shared with the most derived chasmosaurines, Torosaurus and Triceratops. The combination of primitive and derived traits exhibited by B. polyphemus, and its stratigraphic position, is compatible with the gradual transition from basal, to intermediate, to derived chasmosaurines observed throughout the western interior of North America, and with phylogenetic analysis, which suggests that Bravoceratops may be closely related to Coahuilaceratops.
波吕斐摩斯勇角龙（Bravoceratops polyphemus）属及种为一新发现，是一种大型开角龙类角龙科恐龙，来自美国得克萨斯州大弯曲国家公园的哈韦利纳组底部（马斯特里赫特阶早期）。波吕斐摩斯勇角龙具有独特的窄吻部、长有开孔的颈盾、后缘带有中线顶饰的扇形顶骨中棒，以及在顶骨支交汇处的背表面有一个对称凹陷。这个凹陷被解释为第二个中线顶饰的附着点。这种顶骨形态与安氏角龙（Anchiceratops）或五角龙（Pentaceratops）所展示的不同。波吕斐摩斯勇角龙的后中线顶饰及其分叉的方轭骨 - 鳞状骨关节是与最衍生的开角龙类，即牛角龙（Torosaurus）和三角龙（Triceratops）共有的特征。波吕斐摩斯勇角龙所展现的原始特征和衍生特征的组合，以及它的地层位置，与在北美西部内陆观察到的从基础开角龙类到中间开角龙类再到衍生开角龙类的逐渐过渡相一致，并且与系统发育分析结果相符，该分析表明勇角龙可能与科阿韦拉角龙（Coahuilaceratops）关系密切。
