What key anatomical feature defines the Order Ornithischia, placing *Xiaosaurus* within the 'bird-hipped' lineage?
Answer
A pelvis where the pubis bone pointed backward
The defining characteristic that places *Xiaosaurus* within the Order Ornithischia, often referred to as the 'bird-hipped' dinosaurs, is the structure of its pelvis. Specifically, in Ornithischians, the pubis bone—one of the primary bones forming the hip—is oriented backward, pointing toward the tail. This arrangement is structurally similar, though evolutionarily distinct, to the pelvis found in modern birds. This contrasts directly with the Saurischia order (lizard-hipped dinosaurs), which includes groups like sauropods and theropods, where the pubis bone generally points forward.
Related Questions
What is the literal translation of the genus name *Xiaosaurus*?Which specific geological formation yielded the initial fossil remains of *Xiaosaurus*?What key anatomical feature defines the Order Ornithischia, placing *Xiaosaurus* within the 'bird-hipped' lineage?What defining characteristic related to food processing did Fabrosaurids like *Xiaosaurus* generally lack?During which specific time interval is the existence of *Xiaosaurus* generally placed?What scientific classification issue arises from the limited fossil material known for *Xiaosaurus*?Who formally named the genus *Xiaosaurus* and in what year was the genus established?How is the primary mode of locomotion described for the small ornithischian *Xiaosaurus*?What is the specific geographical feature honored by the species name *dashanpensis*?What characterizes the teeth of *Xiaosaurus*, reflecting its herbivorous diet?