Poropat Stephen F, Frauenfelder Timothy G, Mannion Philip D, Rigby Samantha L, Pentland Adele H, Sloan Trish, Elliott David A
Australian Age of Dinosaurs Natural History Museum, The Jump-Up, Winton, Queensland 4735, Australia.
School of Science, Computing and Engineering Technologies, Swinburne University of Technology, John Street, Hawthorn, Victoria 3122, Australia.
R Soc Open Sci. 2022 Jul 13;9(7):220381. doi: 10.1098/rsos.220381. eCollection 2022 Jul.
The Upper Cretaceous Winton Formation of Queensland, Australia, has produced several partial sauropod skeletons, but cranial remains-including teeth-remain rare. Herein, we present the first description of sauropod teeth from this formation, based on specimens from three separate sites. An isolated tooth and a dentary fragment from the type locality are considered to be referable to that titanosaurian taxon. A single tooth from the referred specimen site is similarly regarded as being part of that individual. Seventeen teeth from a new site that are morphologically uniform, and similar to the teeth from the two sites, are assigned to Diamantinasauria. All sauropod teeth recovered from the Winton Formation to date are compressed-cone-chisel-shaped, have low slenderness index values (2.00-2.88), are lingually curved at their apices, mesiodistally convex on their lingual surfaces, and lack prominent carinae and denticles. They are markedly different from the chisel-like teeth of derived titanosaurs, more closely resembling the teeth of early branching members of the titanosauriform radiation. This provides further support for a 'basal' titanosaurian position for Diamantinasauria. Scanning electron microscope microwear analysis of the wear facets of several teeth reveals more scratches than pits, implying that diamantinasaurians were mid-height (1-10 m) feeders. With a view to assessing the spatio-temporal distribution of sauropod tooth morphotypes before and after deposition of the Winton Formation, we provide a comprehensive continent-by-continent review of the early titanosauriform global record (Early to early Late Cretaceous). This indicates that throughout the Early-early Late Cretaceous, sauropod faunas transitioned from being quite diverse at higher phylogenetic levels and encompassing a range of tooth morphologies at the start of the Berriasian, to faunas comprising solely titanosaurs with limited dental variability by the end-Turonian. Furthermore, this review highlights the different ways in which this transition unfolded on each continent, including the earliest records of titanosaurs with narrow-crowned teeth on each continent.
澳大利亚昆士兰州上白垩统温顿组已发现了几具蜥脚类恐龙的部分骨骼，但包括牙齿在内的颅骨遗骸仍然稀少。在此，我们基于来自三个不同地点的标本，首次描述了该地层的蜥脚类恐龙牙齿。来自模式产地的一颗孤立牙齿和一块齿骨碎片被认为可归属于该泰坦巨龙类分类单元。来自参考标本产地的一颗单独牙齿同样被视为该个体的一部分。从一个新地点发现的17颗形态一致且与另外两个地点的牙齿相似的牙齿，被归入迪亚曼蒂纳龙类。迄今为止从温顿组发现的所有蜥脚类恐龙牙齿均呈压缩圆锥凿形，细长指数值较低（2.00 - 2.88），顶端舌侧弯曲，舌面近远中凸，且没有明显的嵴和小齿。它们与衍生泰坦巨龙类的凿状牙齿明显不同，更类似于泰坦巨龙形类演化早期分支成员的牙齿。这为迪亚曼蒂纳龙类处于“基础”泰坦巨龙类地位提供了进一步支持。对几颗牙齿磨损面的扫描电子显微镜微磨损分析显示，划痕比凹坑更多，这意味着迪亚曼蒂纳龙类是中等高度（1 - 10米）的取食者。为了评估温顿组沉积前后蜥脚类恐龙牙齿形态类型的时空分布，我们对早期泰坦巨龙形类的全球记录（早白垩世至晚白垩世早期）进行了全面的逐大陆综述。这表明在整个早白垩世到晚白垩世早期，蜥脚类动物群从在较高系统发育水平上相当多样化且在贝里亚阶开始时包含一系列牙齿形态，转变为到土伦期末仅由牙齿变异性有限的泰坦巨龙类组成的动物群。此外，这次综述突出了这种转变在每个大陆上展开的不同方式，包括每个大陆上窄冠牙齿泰坦巨龙类最早的记录。
