The fossil record of Late Cretaceous non-hadrosaurid neornithischians from the Western Interior of North America is sparse. Parksosaurus warreni is an early Maastrichtian taxon currently known only from a skull and much of the associated postcranial skeleton and a referred isolated tooth from the Horseshoe Canyon Formation of Alberta, Canada. This article presents a detailed anatomical account of the holotype of this species following extensive additional preparation of the holotype and provides photographs of the postcranial elements for the first time. The premaxilla has a dorsoventrally deep posterolateral process, which overlaps the maxilla. The antorbital fenestra is small and teardrop-shaped. The lingual surfaces of dentary teeth bear nine or 10 vertically extending ridges that terminate in apical denticles. The suprascapula is mineralized or ossified. The dorsal margin of the ischium is posterodorsally concave at mid-length. The greater and lesser trochanters of the femur are not separated by a distinct cleft. The pendent fourth trochanter is placed on the proximal half of the femur. The more distal caudal vertebrae have greatly elongated prezygapophyses, which, together with a basket of ossified tendons ensheathing the caudal vertebrae, indicate that the tail may have functioned as a dynamic stabilizer during locomotion. The substantial new anatomical information from the holotype and only known skeleton of Parksosaurus warreni will allow more detailed comparisons to other closely related taxa and facilitate further discussions of unresolved aspects of the interrelationships of neornithischian dinosaurs.

来自北美西部内陆的晚白垩纪非鸭嘴龙类新鸟臀目化石记录稀少。巴索龙是一个早期的马斯特里赫特分类群，目前仅从头骨和大部分相关的颅后骨骼以及来自加拿大艾伯塔省马蹄峡谷地层的提到的孤立牙齿中获知。本文在对正模标本进行大量额外准备后，对该物种的正模标本进行了详细的解剖学描述，并首次提供了颅后元素的照片。前上颌骨有一个背腹深的后外侧突，与上颌骨重叠。眶前窗很小，呈泪珠状。牙齿的舌面有九或十个垂直延伸的脊，终止于顶端细齿。肩胛骨被矿化或骨化。坐骨的背缘在中长处后背凹入。股骨的大转子和小转子之间没有明显的裂隙。下垂的第四大转子位于股骨的近半部分。更远端的尾椎骨有大大拉长的前关节突，连同包裹尾椎骨的一篮子骨化肌腱，表明尾巴在运动过程中可能起到了动态稳定器的作用。来自正模标本和唯一已知骨骼的大量新解剖信息Parksaurus warreni将允许与其他密切相关的分类群进行更详细的比较，并促进对新鸟臀目恐龙相互关系的未解决方面的进一步讨论。