ANATOMICAL TERMINOLOGY FOR THE SACRUM OF SAUROPOD DINOSAURS

摘要

— The sacrum represents a key anatomical element for understanding Dinosauria, beginning with the first use of the taxon name in 1842. A five-vertebra sacrum was originally considered diagnostic of dinosaurs, and variation in the number of sacral vertebrae has been used to diagnose smaller groups of dinosaurs. Despite its centrality to early definitions of Dinosauria, utility for diagnosing smaller groups, and manifest complexity in certain groups (e.g., sauropods and theropods), the sacrum has played a relatively minor role in determining phylogenetic relationships among dinosaurs. Part of this oversight may be due to the absence of nomenclature to describe the parts of the sacrum. Here I present a nomenclature for the sauropod sacrum that is designed to aid description of the complex structures involved and to facilitate development of novel character data. Although based on sauropods, it is applicable to closely related taxa, such as other sauropodomorphs and theropods.