Data from: Functional niche partitioning in Therizinosauria provides new insights into the evolution of theropod herbivory

Dietary specialization is generally considered to be a crucial factor in driving morphological evolution across extant and extinct vertebrates. The ability to adapt to a specific diet and to exploit ecological niches is thereby influenced by functional morphology and biomechanical properties. Differences in functional behaviour and efficiency can therefore allow dietary diversification and the coexistence of similarly adapted taxa. Therizinosauria, a group of secondarily herbivorous theropod dinosaurs, is characterized by a suite of morphological traits thought to be indicative of adaptations to an herbivorous diet. Digital reconstruction, theoretical modelling and computer simulations of the mandibles of therizinosaur dinosaurs provides evidence for functional niche partitioning in adaptation to herbivory. Different mandibular morphologies present in therizinosaurians were found to correspond to different dietary strategies permitting coexistence of taxa. Morphological traits indicative of an herbivorous diet, such as a downturned tip of the lower jaw and an expanded postdentary region, were identified as having stress mitigating effects. The more widely distributed occurrence of these purported herbivorous traits across different dinosaur clades suggests that these features also could have played an important role in the evolution and acquisition of herbivory in other groups.饮食特化通常被认为是驱动现生及已灭绝脊椎动物形态演化的关键因素。对特定饮食的适应能力与生态位开拓能力，均受功能形态学及生物力学特性的影响。因此，功能行为与效能的差异可推动饮食多元化，并使得适应性相似的类群得以共存。镰刀龙类（Therizinosauria）是一类次生性植食性兽脚亚目恐龙，其特征为一系列被认为反映植食性适应的形态性状。针对镰刀龙类恐龙下颌骨开展的数字化重建、理论建模与计算机模拟，为其适应植食性时的功能生态位分化提供了证据。研究发现，镰刀龙类所具备的不同下颌骨形态，对应着各异的饮食策略，进而实现类群间的共存。反映植食性的形态性状——如下颌骨前端下弯、齿后区域扩张——被证实具有应力缓解作用。这类被认为与植食性相关的性状在不同恐龙演化支中的分布更为广泛，这表明这些特征在其他类群的植食性演化与获得过程中，或许也发挥了重要作用。