Abstract: Sabertooth cats were extinct carnivorans that have attracted great attention and controversy because of their unique dental morphology representing an entirely extinct mode of feeding specialization. Some of themare lion-sized or tiger-sized carnivorans who are widely interpreted as hunters of larger and more powerful preys than those of their modern nonsaber-toothed relatives. We report the discovery of a large sabertooth cat skull ofMachairodus horribilis from the Late Miocene of northwestern China. It shares some characteristics with derived sabertooth cats, but also is similar to extant pantherines in some cranial characters. A functional morphological analysis suggests that it differed from most other machairodont felids and had a limited gape to hunt smaller preys. Its anatomical features provide new evidence for the diversity of killing bites even within in the largest saber-toothed carnivorans and offer an additional mechanism for the mosaic evolution leading to functional and morphological diversity in sabertooth cats. 

摘要： 剑齿虎是一类绝灭的食肉目动物，由于其独特的牙齿形态代表了已完全消失的特化取食方式而引起了极大的关注和争论。一些剑齿虎是狮子体型或老虎体型的食肉动物，它们被广泛认为能够比其不具剑形犬齿的现代近亲捕杀更大和更强壮的猎物。本文报道在甘肃省晚中新世地层中发现的一具属于恐剑齿虎(Machairodus horribilis)的大型头骨。这件标本的一些特征与进步的剑齿虎相同，但在某些头骨性状上则与现生的豹亚科种类相似。不同于其他大多数剑齿虎，功能形态分析指示该剑齿虎的口部张开程度受到限制，因此只能捕猎相对较小的猎物。这具头骨的解剖特征为证明即使在最大的具剑形犬齿的食肉目动物中也存在捕猎咬杀方式的多样性提供了新的证据，并揭示了在剑齿虎中导致功能和形态多样性镶嵌进化的另一种机制。