Therizinosaurs were a taxon of unusual theropods from North America and Asia. The derived therizinosaur Nothronychus graffami possessed a synsacrum and hip convergent with extant birds. The osteology is figured and described in detail supplemented with material from Nothronychus mckinleyi. Both species exhibit traits convergent with extant birds, ornithischian dinosaurs, and titanosaurs. As preserved, the ilia and sacrum are minimally distorted and apomorphically modified into a synsacrum. The pubes are modified into a mesopubic condition, wherein the pubes are partially retroverted. The femoral shaft has an oval cross-section. As these characters are absent from the basal therizinosaur Falcarius utahensis, they evolved more than once within the maniraptoran lineage. An herbivorous ecology is supported. Both specimens were skeletally mature, based on fusion of the neural spines and scapulocoracoid.

中文翻译：

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衍生镰刀龙Nothronychus的骨学以及恐龙进化趋同的证据

镰刀龙是来自北美和亚洲的不寻常兽脚类恐龙的一个分类群。衍生的镰刀龙Nothronychus graffami 拥有与现存鸟类趋同的合骶骨和臀部。对骨学进行了详细的描绘和描述，并补充了来自麦金利野爪螨的材料。这两个物种都表现出与现存鸟类、鸟臀目恐龙和泰坦龙相似的特征。在保存时，髂骨和骶骨被最小程度地扭曲并变形为合骶骨。将阴毛修改为阴毛中阴状态，其中阴毛部分后倾。股骨干具有椭圆形横截面。由于这些特征在基础镰刀龙 Falcarius utahensis 中不存在，因此它们在手盗龙谱系中进化了不止一次。支持草食生态。基于神经棘和肩胛喙骨的融合，两个标本的骨骼均已成熟。